EXO-18-010

$HeadURL:svn+ssh://svn.cern.ch/reps/tdr2/papers/EXO-18-010/trunk/EXO-18-010.tex$
$Id:EXO-18-010.tex4907972019-03-0317:32:59Zalverson$

EXO-18-010

# Search for dark matter produced in association with a single top quark or a
top quark pair in proton-proton collisions at $\sqrt{s}=13\TeV$

###### Abstract

A search for dark matter produced in association with top quarks in proton-
proton collisions at a center-of-mass energy of 13is presented. The data set
used corresponds to an integrated luminosity of 35.9recorded with the CMS
detector at the LHC. Whereas previous searches for neutral scalar or
pseudoscalar mediators considered dark matter production in association with a
top quark pair only, this analysis also includes production modes with a
single top quark. The results are derived from the combination of multiple
selection categories that are defined to target either the single top quark or
the top quark pair signature. No significant deviations with respect to the
standard model predictions are observed. The results are interpreted in the
context of a simplified model in which a scalar or pseudoscalar mediator
particle couples to a top quark and subsequently decays into dark matter
particles. Scalar and pseudoscalar mediator particles with masses below 290
and 300, respectively, are excluded at 95% confidence level, assuming a dark
matter particle mass of 1and mediator couplings to fermions and dark matter
particles equal to unity.

##  0.1 Introduction

Astrophysical observations provide evidence of the existence of nonluminous
matter that can be inferred from gravitational effects on galaxies and other
large scale objects in the Universe. While the nature of this dark matter (DM)
is still unknown, a compelling candidate is the so-called weakly interacting
massive particle [1]. This new particle is predicted to have weak interactions
with standard model (SM) particles, allowing for direct- and indirect-
detection experiments, as well as for searches at collider experiments.

Among all the possible interactions between the SM and DM sectors, it is of
particular interest to investigate interactions mediated by a new neutral
scalar or pseudoscalar particle that decays into DM particles, as these can be
easily accommodated in models containing extended Higgs boson sectors [2, 3,
4, 5]. Assuming that this DM scenario respects the principle of minimal flavor
violation [6, 7], the interactions of this new spin-0 mediator particle follow
the same Yukawa coupling structure as in the SM. Therefore, the mediator would
couple preferentially to heavy third-generation quarks. Assuming the DM
particles to be Dirac fermions, the interaction Lagrangian terms for the
production of a scalar ($\phi$) or pseudoscalar () mediator particle can be
expressed as:

$\displaystyle\mathcal{L}_{\phi}$ $\displaystyle\supset
g_{\chi}\phi\overline{\chi}\chi+\frac{g_{\cPq}\phi}{\sqrt{\smash[b]{2}}}\sum_{\mathrm{f}}(y_{\mathrm{f}}\overline{\mathrm{f}}\mathrm{f})$
$\displaystyle\mathcal{L}_{\Pa}$ $\displaystyle\supset
ig_{\chi}\Pa\overline{\chi}\gamma^{5}\chi+\frac{ig_{\cPq}\Pa}{\sqrt{\smash[b]{2}}}\sum_{\mathrm{f}}(y_{\mathrm{f}}\overline{\mathrm{f}}\gamma^{5}\mathrm{f}),$
(1)

where the sum runs over the SM fermions $\mathrm{f}$,
$y_{\mathrm{f}}=\sqrt{\smash[b]{2}}m_{\mathrm{f}}/v$ represents the Yukawa
couplings, $v=246\GeV$ is the Higgs field vacuum expectation value, $g_{\chi}$
is the DM-mediator coupling, and $g_{\cPq}$ is the fermion-mediator coupling.
The mediator particle subsequently decays into DM particles, which escape
detection and leave an imbalance of momentum in the transverse plane, referred
to as . Several theoretical studies of these types of models have been
performed, in which the third-generation quark is either a top or bottom
quark, leading to the production of DM in association with a pair of top
($\ttbar$+DM) or bottom ($\bbbar$+DM) quarks, respectively [8, 9, 10, 11]. The
main production diagram for $\ttbar$+DM processes is shown in Fig. 1 (upper
left).

Figure 1: Principal production diagrams for the associated production at the
LHC of dark matter with a top quark pair (upper left) or a single top quark
with associated $t$ channel boson production (upper right) or with associated
t production (lower left and right).

Previous searches in these final states have been carried out by the ATLAS and
CMS Collaborations at center-of-mass energies of 8[12, 13] and 13[14, 15, 16].
While the former results are based on an effective field theory (EFT)
approach, the latter ones are interpreted in the context of simplified DM
scenarios, where the mediator particle is explicitly modeled in the
interaction. These interpretations have so far neglected the contribution from
DM production in association with a single top quark
(${\cPqt}/\overline{{\cPqt}}$+DM) in which the interaction is mediated by a
neutral spin-0 particle, as pointed out in Ref. [17]. As in the SM, the single
top quark is produced through processes mediated by a virtual $t$ channel
(Fig. 1, upper right) or through associated production with a boson (Fig. 1,
lower left and right) [17]. While the $s$ channel production of a boson is
also possible, this process is found to have a negligible contribution for
this search. The neutral DM mediator particle is then produced either by
radiation from the top quark or via top quark fusion, as described in Ref.
[18] for the associated production of DM with a top quark pair.

In this search, ${\cPqt}/\overline{{\cPqt}}$+DM processes mediated by a
neutral spin-0 particle are investigated for the first time. This additional
production mechanism is predicted by the same interactions described in Eqs.
(0.1) and (1) that also predict $\ttbar$+DM events. For this reason, in the
presented search ${\cPqt}/\overline{{\cPqt}}$+DM and $\ttbar$+DM processes are
both considered. Searches for similar final states referred to as “monotop”,
which involve the production of a top quark and DM particles but without
additional jets or bosons, have been conducted by the CDF experiment [19] at
the Fermilab Tevatron, by the ATLAS and CMS Collaborations [20, 21] at the
CERN LHC at center-of-mass energies of 8, and at 13by the CMS Collaboration
[22]. The underlying simplified models explored in these results, unlike the
one presented in Eqs. (0.1) and (1), assume either the resonant production of
a +2/3 charged and colored spin-0 boson that decays into a right-handed top
quark and one DM particle, or a spin-1 mediator with flavor changing neutral
current interactions. Considering these models, in addition to the DM
particle, only one top quark is assumed to be produced in the final state,
unlike the ${\cPqt}/\overline{{\cPqt}}$+DM processes considered in this search
where the top quark is produced through SM-like diagrams alongside a light
quark or a boson (Fig. 1).

In this paper we present a search for an excess of events above the SM
background in the spectrum, as expected for the DM scenarios discussed
earlier, for events that contain exactly one lepton (electron or muon) or zero
leptons, henceforth assigned to the “single-lepton” (SL) region or to the
“all-hadronic” (AH) region, respectively. The sensitivity of this analysis is
improved beyond that of previous analyses by introducing a categorization of
these signatures and new discriminating variables, as discussed in more detail
in Section 0.4.

##  0.2 The CMS detector and event reconstruction

The central feature of the CMS apparatus is a superconducting solenoid of 6m
internal diameter, providing a magnetic field of 3.8T. Within the solenoid
volume are a silicon pixel and strip tracker, a lead tungstate crystal
electromagnetic calorimeter (ECAL), and a brass and scintillator hadron
calorimeter (HCAL), each composed of a barrel and two endcap sections. Forward
calorimeters extend the pseudorapidity ($\eta$) coverage provided by the
barrel and endcap detectors. Muons are detected in gas-ionization chambers
embedded in the steel flux-return yoke outside the solenoid. A more detailed
description of the CMS detector, together with a definition of the coordinate
system used and the relevant kinematic variables, can be found in Ref. [23].

Events of interest are selected using a two-tiered trigger system [24]. The
first level, composed of custom hardware processors, uses information from the
calorimeters and muon detectors to select events at a rate of around 100kHz
within a time interval of less than 4. The second level, known as the high-
level trigger, consists of a farm of processors running a version of the full
event reconstruction software optimized for fast processing, and reduces the
event rate to around 1kHz before data storage.

The particle-flow (PF) algorithm [25] aims to reconstruct and identify each
individual particle in an event, with an optimized combination of information
from the various elements of the CMS detector. The energy of photons is
obtained directly from the ECAL measurement and corrected for zero-suppression
effects. The energy of electrons is obtained from a combination of the
electron momentum at the primary interaction vertex as determined by the
tracker, the energy of the corresponding ECAL cluster, and the energy sum of
all bremsstrahlung photons spatially compatible with originating from the
electron track. The muon track is obtained from the combination of central
tracker and muon system information, and its curvature provides an estimate of
the momentum. The energy of charged hadrons is determined from a combination
of their momentum measured in the tracker and the matching ECAL and HCAL
energy deposits, corrected for zero-suppression effects and for the response
function of the calorimeters to hadronic showers. Finally, the energy of
neutral hadrons is obtained from the corresponding corrected ECAL and HCAL
energy.

The reconstructed vertex with the largest value of summed physics-object
$\pt^{2}$, where is the transverse momentum, is taken to be the primary
proton-proton () interaction vertex. The physics objects are the jets and the
associated , taken as the negative vector sum of those jets. For each event,
hadronic jets are clustered from the particles reconstructed with PF (PF
candidates) using the infrared- and collinear-safe anti-algorithm [26, 27]
with a distance parameter of 0.4. The jet momentum is determined as the
vectorial sum of all particle momenta in the jet, and is found from simulation
to be within 5 to 10% of the parton’s generated momentum over the whole
spectrum and detector acceptance. Additional interactions within the same or
nearby bunch crossings (pileup) can contribute additional tracks and
calorimetric energy depositions to the jet momentum. To mitigate this effect,
tracks identified as originating from pileup vertices are discarded and an
offset correction is applied to correct for remaining contributions [28]. Jet
energy corrections are derived from simulation and applied to calibrate the
jet momentum. In situ measurements of the momentum balance in dijet,
photon+jet, $\PZ$+jets, and multijet events are used to account for any
residual differences in jet energy scale in data and simulation [29].
Additional selection criteria are applied to each jet to remove jets
potentially dominated by anomalous contributions from various subdetector
components or reconstruction failures [29].

The combined secondary vertex tagging algorithm (CSVv2) is used to identify
jets originating from the hadronization of bottom quarks [30], denoted in the
following as “-tagged jets”. At the operating point of the tagging algorithm
chosen for this analysis, the efficiency of identifying quark jets in
simulated events is about 80%, integrated over , and the misidentification
rate for light-flavor jets is about 1%. Scale factors are applied to the
simulated samples in order to reproduce the tagging performance measured in
data.

The missing transverse momentum vector is defined as the negative vector sum
of all PF particles originating from the primary vertex; its magnitude is
defined as . Jet energy scale and resolution corrections are also propagated
to the calculation.

##  0.3 Data sample and simulation

The data used in this search were recorded with the CMS detector in 2016 and
correspond to an integrated luminosity of 35.9. Several trigger criteria were
used to collect the data, either requiring large amounts of or the presence of
at least one high-lepton (electron or muon). Simulated samples are corrected
to reproduce the observed trigger efficiencies in data.

Specifically, events that do not contain leptons are selected if they have and
missing hadronic activity [24] above 120. This trigger is nearly 100%
efficient for events with of at least 250. The second set of triggers requires
the presence of at least one isolated electron (muon) with $\pt>27$ (25). The
corresponding trigger efficiencies are above 90% for leptons with
$\pt>30\GeV$. Trigger efficiencies are measured in data.

Monte Carlo (MC) simulated samples of the main SM backgrounds and of the DM
signal processes are used to optimize the event selection, assess our
sensitivity to the new-physics scenarios, and form the basis of our background
estimation strategy. While the detailed background composition depends on the
specific channel, the main sources arise from $\ttbar$+jets, $\PW$+jets, and
$\PZ$+jets production. Simulated events of $\ttbar$+jets production and single
top quark processes are generated at next-to-leading order (NLO) in quantum
chromodynamics (QCD) using v2 and v1 [31, 32, 33], respectively. For
$\ttbar$+jets processes, the top quark distribution is reweighted to reproduce
the differential cross section obtained from CMS measurements [34]. Samples of
$\PZ$+jets, $\PW$+jets, and QCD multijet events are generated at leading order
(LO) using [35] with the MLM prescription [36] for matching jets from the
matrix element (ME) calculation to the parton shower description. Dedicated
electroweak [37, 38, 39, 40, 41, 42] and QCD (calculated with ) NLO/LO $K$
factors, parametrized as functions of the generated boson , are applied to
$\PZ$+jets and $\PW$+jets events. Other SM backgrounds include rare processes,
such as $\ttbar$\+ and $\ttbar$+, which are simulated based on the NLO ME
calculations implemented in and the FxFx [43] prescription to merge multileg
processes. Diboson processes ($\PW\PW$, $\PW\PZ$, $\PZ\PZ$, $\PW\PH$,
$\PZ\PH$) are generated at NLO using either or v2. All background samples are
normalized using the most accurate cross section calculations available, which
generally incorporate NLO or next-to-NLO (NNLO) precision.

The signal process is simulated at LO with the v2.4.2 event generator using a
simplified model investigated within the LHC Dark Matter Forum [44]. In this
model, the DM particles $\chi$ are assumed to be Dirac fermions and the
mediators are spin-0 particles $\phi$ () that couple preferentially to third-
generation SM quarks through scalar (pseudoscalar) couplings whose strengths
are parametrized by the factor $g_{\cPq}$. The coupling strength between the
mediator and the DM particles is in turn given by the factor $g_{\chi}$. This
simplified model has a minimal set of four free parameters: (${m}_{\chi},\
m_{\phi/\Pa},\ g_{\chi},\ g_{\cPq}$), and the benchmark scenarios assume
$g_{\chi}=g_{\cPq}=1$ as per recommendations of the LHC Dark Matter Working
Group [45]. In addition, in this search we focus on the ${m}_{\chi}=1\GeV$
benchmark, which is a convenient signal reference as the production cross
section is almost independent of ${m}_{\chi}$ for on-shell mediators [44].
This simplified spin-0 model does not account for mixing between the $\phi$
scalar mediator and the SM Higgs boson, as discussed in Ref. [46]. Under these
assumptions two distinct DM scenarios are possible: the associated production
with a top quark pair ($\ttbar$+DM) and the associated production with a
single top quark (${\cPqt}/\overline{{\cPqt}}$+DM). Cross sections for both
signal processes are calculated at LO with v2.4.2, with one (zero) additional
partons for $\ttbar$+DM (${\cPqt}/\overline{{\cPqt}}$+DM) events.

For all simulated samples, the initial-state partons are modeled with the
NNPDF 3.0 [47] parton distribution function (PDF) sets at LO or NLO in QCD to
match the ME calculation. Generated events are interfaced with 8.205 [48] for
parton showering and hadronization using the CUETP8M1 tune [49], except for
simulated $\ttbar$+jets events where the CUETP8M2 tune customized by CMS with
an updated strong coupling for initial-state radiation is employed [50]. All
signal and background samples are processed using [51] to provide a full
simulation of the CMS detector, including a simulation of the previously
mentioned triggers. Correction factors are derived and applied to the
simulated samples to match the trigger efficiencies measured in data.
Additional corrections are applied to cover remaining residual differences
between data and simulation that arise from the lepton identification and
reconstruction efficiencies, as well as from -tagged jet identification
efficiencies.

##  0.4 Event selection

This search, similarly to a previous search for $\ttbar$+DM events [16],
defines several orthogonal signal regions (SRs) that are statistically
combined in a simultaneous global fit of the spectrum. At the same time,
various improvements are incorporated into this search to enhance the
sensitivity to the ${\cPqt}/\overline{{\cPqt}}$+DM final state over that of
previous analyses [16].

At the analysis level, jet candidates are required to have $\pt>30\GeV$ and
are categorized as “central” if they lie within $\abs{\eta}<2.4$ and as
“forward” if they are within $2.4<\abs{\eta}<4.0$. The -tagged jets identified
by the CSVv2 algorithm are also required to have $\pt>30\GeV$ and in addition
to lie within $\abs{\eta}<2.4$. Electrons and muons are selected with
$\pt>30\GeV$ and $\abs{\eta}<2.1$. Events containing additional leptons with
$\pt>10\GeV$ and $\abs{\eta}<2.1$ are vetoed. To ensure that candidate leptons
are well-measured, identification requirements, based on hit information in
the tracker and muon systems and on energy deposits in the calorimeters, are
imposed. Leptons are further required to be isolated from hadronic activity,
to reject leptons within jets that could arise, for example, from the decay of
quarks. A relative isolation quantity is defined as the scalar sum of all PF
candidates within a
$\Delta{R}=\sqrt{\smash[b]{(\Delta\eta)^{2}+(\Delta\phi)^{2}}}$ cone of radius
0.3 (0.4) centered around the electron (muon) candidate, where $\phi$ is the
azimuthal angle in radians, divided by the lepton [52, 53]. This relative
isolation is required to be less than 0.059 (0.057) for electrons in the
barrel (endcap) and less than 0.15 for muons.

Events are separated into orthogonal categories based on the number of -tagged
jets ($n_{\PQb}$), with $n_{\PQb}=1$ or $n_{\PQb}\geq 2$, and additional
requirements on the number of forward jets are placed (0 or ${\geq}1$ forward
jets) for the $n_{\PQb}=1$ category. The mentioned categorization in terms of
forward jets allows a further enhancement of ${\cPqt}/\overline{{\cPqt}}$+DM
$t$ channel events. In fact, as shown in Fig. 1, this production mode leads to
final states with one top quark and an additional jet, which tends to be in
the forward region of the detector, while the additionally produced quark is
typically low in and therefore is not reconstructed. The minimum requirements
on the number of jets is also lowered, with respect to the previous searches,
to enhance the sensitivity specifically to the ${\cPqt}/\overline{{\cPqt}}$+DM
model. Control regions (CRs) enriched in the major background processes are
included in the fit in order to improve the estimates of the background
contributions.

Events are classified into two “channels”, based on the number of leptons in
the final state from the top quark decay: the single-lepton SL channel,
containing events with exactly one electron or muon with $\pt>30\GeV$, and the
all-hadronic AH channel, containing events with exactly zero leptons with
$\pt>10\GeV$. A set of discriminating variables is identified, as discussed in
more detail in Sections 0.4.1 and 0.4.2 for the SL SRs and the AH SRs,
respectively. The selection requirements on these variables are optimized
simultaneously to increase the signal significance, using as a figure of merit
the ratio between the expected number of signal and the square root of the
expected SM background events. The considered signal events are either
${\cPqt}/\overline{{\cPqt}}$+DM events for a region that contains exactly one
-tagged jet ($n_{\PQb}=1$) or $\ttbar$+DM events for a region that contains
two or more -tagged jets ($n_{\PQb}\geq 2$). The region with exactly one
-tagged jet is further divided into exactly zero or ${\geq}1$ forward jets.

###  0.4.1 Single-lepton signal regions

Events in the SL channel are required to contain ${\geq}1$ identified -tagged
jet, at least 2 jets with $\pt>30\GeV$, and $\ptmiss>160\GeV$. After this
selection, the dominant backgrounds in the SL channel are from and $\PW$+jets
processes. Other backgrounds include single top quark, Drell–Yan, and diboson
production.

To further improve the sensitivity and to reduce the dominant background from
single-lepton and $\PW$+jets processes, we impose a requirement on the
transverse mass , calculated as:

$\mT=\sqrt{\smash[b]{2\ptmiss\pt^{\ell}[1-\cos(\Delta\phi)]}},$ (2)

where $\pt^{\ell}$ is the transverse momentum of the lepton and $\Delta\phi$
is the opening angle between the lepton direction and the vector in the
transverse plane. The variable is constrained by kinematic properties to be
less than the boson mass for leptonic on-shell decays in and $\PW$+jets
events, while for signals, off-shell decays, or for dileptonic decays of , the
variable is expected to exceed the mass because of the additional in the
event. A requirement of $\mT>160\GeV$ therefore reduces the background from
single-lepton events significantly and enhances the analysis sensitivity to
the DM models.

After the selection, the remaining background is primarily from events where
both top quarks decay leptonically ($\ttbar(2\ell)$) and one lepton is not
identified. This background can be further reduced by making use of the
$\mTii^{\PW}$ variable [54], which is defined as the minimal value of the mass
of a particle assumed to be pair produced and to decay to a boson and a quark
jet. The bosons are assumed to be produced on-shell and to decay leptonically,
where one of the two leptons is not detected. Based on the variable
definition, in $\ttbar(2\ell)$ events the $\mTii^{\PW}$ distribution has a
kinematic end point at the top quark mass, assuming perfect detector response,
while this is not the case for signal events where two additional DM particles
are present. The calculation of $\mTii^{\PW}$ requires two -tagged jets from
the decay of the top quarks, where one of these -tagged jets comes from the
same decay chain as the reconstructed lepton. If only one -tagged jet is
identified in the event, each of the first three (or two in three-jet events)
leading non--tagged jets is considered as the second -tagged jet in the
calculation. The $\mTii^{\PW}$ is then evaluated for all possible jet-lepton
combinations and the minimum $\mTii^{\PW}$ value is considered to discriminate
between signal and background events. If two or more -tagged jets are
identified in the events, all -tagged jets are considered and similarly all
possible jet-lepton combinations are used to calculate $\mTii^{\PW}$ values.
The smallest of all the $\mTii^{\PW}$ values is taken as the event
discriminant.

In addition, jets and the vector tend to be more separated in the transverse
plane in signal events than in background processes. To improve the search
sensitivity, the minimum opening angle
$\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ in the transverse plane
between the direction of each of the first two leading-jets with
$\abs{\eta}<2.4$ and the vector is required to be greater than $1.2$ radians.

The background is further reduced by requiring that the transverse mass
$\mT^{\cPqb}$ of the vector and of a -tagged jet is greater than 180, where
$\mT^{\cPqb}$ is defined similarly to Eq. (2) but considering a -tagged jet
instead of a lepton. In fact, for the remaining background $\mT^{\cPqb}$ tends
to have values below or around the top quark mass if the -tagged jet belongs
to the top quark whose lepton is not identified. For the calculation we choose
the -tagged jet with the highest CSVv2 discriminant value, if there is more
than one candidate.

A summary of the selection criteria for the SL SRs is shown in the first three
columns of Table 0.4.1. Each region is identified by a unique name, where
0$\ell$ denotes exactly zero leptons, 1(2) -tag represents exactly 1 (at least
2) -tagged jet, and 0 FJ or 1 FJ denotes exactly zero or at least one forward
jet.

Final event selections for the SL and AH SRs. Electrons and muons are kept
separate for the SL channel.  Single-lepton SRs All-hadronic SRs 1$\ell$, 1
-tag, 0 FJ 1$\ell$, 1 -tag, 1FJ 1$\ell$, 2 -tag 0$\ell$, 1 -tag, 0 FJ
0$\ell$,1 -tag, 1 FJ 0$\ell$, 2 -tag Forward jets $=$0 ${\geq}1$ $=$ 0
${\geq}1$ $n_{\PQb}$ $=$1 $=$1 ${\geq}2$ $=$ 1 $=$1 ${\geq}2$ $n_{\text{lep}}$
$=$1 $=$1 $=$1 $=$ 0 $=$0 $=$0 $\pt(\mathrm{j_{1})}/\HT$ $<$0.5
$n_{\text{jet}}$ ${\geq}2$ ${\geq}3$ $>$160 $>$250 $>$160 $\mTii^{\PW}$ $>$200
$\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ $>$1.2rad. $>$1.0rad.
$\mT^{\cPqb}$ $>$180 $>$180

###  0.4.2 All-hadronic signal regions

Events categorized into the AH channel must contain at least 1 identified
-tagged jet and at least 3 jets with $\pt>30\GeV$, $\ptmiss>250\GeV$, and
$\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ greater than 0.4 radians.

The dominant backgrounds after this selection arise from , $\PW$+jets, and
${\cPZ}\to\nu\nu$ processes. Other backgrounds include QCD multijet events,
single top quark, Drell–Yan, and diboson production.

Semileptonic events populate this channel if the lepton in the final state is
not identified. This $\ttbar(1\ell)$ background is reduced by applying the
same $\mT^{\cPqb}$ selection as introduced in the SL channel. To further
reduce the $\ttbar(1\ell)$ background, together with that from
${\cPZ}\to\nu\nu$ events, we make use of the $\pt(\mathrm{j_{1})}/\HT$
variable, which is defined as the ratio of the leading jet in the event
divided by the total hadronic transverse energy in the event, , which is the
scalar sum of the jets with $\pt>30\GeV$ within $\abs{\eta}<2.4$. In the case
of background, the distribution peaks at higher values with respect to
$\ttbar$+DM signal events. The ${\cPqt}/\overline{{\cPqt}}$+DM events,
however, tend to exhibit a distribution similar to that of the background.
Events in the $n_{\PQb}\geq 2$ category are required to have
$\pt(\mathrm{j_{1})}/\HT<0.5$.

For QCD multijet events no intrinsic is expected. Therefore, events that pass
our minimum selection contain mostly which arises from jet mismeasurements.
For these events, the is often aligned with one of the leading jets. As a
result, selecting events with
$\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ values greater than 1
radian reduces the background from QCD multijet production. This contribution
to the SR, estimated through simulated samples, is negligible. The description
of the QCD multijet background basic kinematic distributions is verified in a
dedicated region enriched in multijet events, obtained by reversing the
$\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ selection, and the
simulation is found to model the data well.

A summary of the selection criteria for the AH SRs is shown in the last three
columns of Table 0.4.1. Each region is identified by a unique name, where
1$\ell$ denotes exactly one muon or one electron, 1(2) -tag represents exactly
1 (at least 2) -tagged jet, and 0 FJ or 1 FJ denotes exactly zero or at least
one forward jet.

###  0.4.3 Control regions

After events are categorized according to the selection presented in Table
0.4.1, the expected SM backgrounds in these different regions must be
evaluated. In the SL SRs, the main backgrounds are dileptonic events, where
one lepton is not identified, and $\PW$+jets events. For the AH regions the
main backgrounds arise instead from single-lepton and $\PW$+jets events, where
the lepton is not identified, and boson production, where the boson decays
into two neutrinos and leads to a background with genuine .

In order to improve the estimation of these main backgrounds, methods based on
control samples in data are used. In particular, CRs enhanced in the different
background sources are used to derive correction factors as a function of the
from the comparison of the distribution between the data and the simulation.
These corrections are extracted and simultaneously propagated across the CRs
and SRs for a given channel in the context of a global fit, as explained in
more detail in Section 0.6. The residual backgrounds processes are modeled
with simulation.

The background CRs for the SL and AH channels are designed to be statistically
independent from the corresponding SRs.

#### Single-lepton control regions

The first set of CRs is defined to isolate dileptonic events by requiring
exactly two leptons (1 electron and 1 muon, 2 electrons, or 2 muons),
$n_{\text{jet}}\geq 2$, $n_{\PQb}\geq 1$, and $\ptmiss>160\GeV$. In order to
statistically enhance these CRs the , $\mTii^{\PW}$, and forward jet
selections are removed.

The second set of CRs is designed to isolate $\PW$+jets events by requiring
exactly one lepton (electron or muon), $n_{\text{jet}}\geq 2$, $n_{\PQb}=0$,
$\ptmiss>160\GeV$, and $\mT>160\GeV$. The $n_{\PQb}=0$ requirement makes this
CR orthogonal to the SL SR and allows the events in the tail to be modeled
without extrapolation from a lower-region.

Both of these selections are summarized in the first two columns of Table
0.4.3.

Control regions defined for the main backgrounds of the SL SRs (first two
columns, $\ttbar(2\ell)$ and $\PW$+jets) and the AH SRs (last 3 columns,
$\ttbar(1\ell)$, $\PW$+jets, and ${\cPZ}\to\ell\ell$). Some selections applied
in the SRs are removed in the corresponding CRs to increase the available
statistics and are therefore not listed. The selection for the
${\cPZ}\to\ell\ell$ CR refers to the hadronic recoil.  Single-lepton CRs All-
hadronic CRs CR $\ttbar(2\ell)$ CR ($\ell\nu$) CR $\ttbar(1\ell)$ CR
($\ell\nu$) CR ($\ell\ell$) $n_{\PQb}$ ${\geq}1$ $=$0 ${\geq}1$ $=$0 $=$0
$n_{\text{lep}}$ $=$2 $=$1 $=$1 $=$1 $=$2 $n_{\text{jet}}$ ${\geq}2$ ${\geq}2$
${\geq}3$ ${\geq}3$ ${\geq}3$ $>$160 $>$160 $>$250 $>$250 $>$250 $>$160 $<$160
$<$160 $\text{min}\Delta\phi(\mathrm{j_{1,2}},\ptvecmiss)$ $>$1.0rad.
$m_{\ell\ell}$ $[60,120]$

#### All-hadronic control regions

For the AH SRs, three independent sets of CRs are defined. The first set of
CRs is enhanced in single-lepton events selecting events with exactly one
lepton (electron or muon), $n_{\text{jet}}\geq 3$, $n_{\PQb}\geq 1$,
$\ptmiss>250\GeV$, and, in order to avoid overlap with the SL SRs,
$\mT<160\GeV$.

The second set of CRs is defined to enhance single-lepton $\PW$+jets events.
Events are selected with exactly one lepton (electron or muon),
$n_{\text{jet}}\geq 3$, $n_{\PQb}=0$, $\ptmiss>250\GeV$, and in order to avoid
overlap with the SL $\PW$+jets CR, $\mT<160\GeV$.

The third and last set of CRs are designed to model the background due to
$\PZ$+jets production, where the boson decays into a pair of neutrinos
(${\cPZ}\to\nu\nu$). Here we use the boson decays to an opposite-sign, same-
flavor dilepton pair (${\cPZ}\to\ell\ell$), as proxy events to emulate the
kinematic properties of the $\PZ$+jets process. Events are selected requiring
2 leptons, which have the same flavor (, or $\mu\mu$), and opposite charge,
and that satisfy a requirement on their invariant mass of
$60<m_{\ell\ell}<120\GeV$. Additionally, events must contain at least 3 jets,
but events with -tagged jets are vetoed ($n_{\PQb}=0$). In order to reproduce
the spectrum of ${\cPZ}\to\nu\nu$ events, the two leptons are added to the ,
referred to as hadronic recoil.

A summary of the different AH CRs can be found in the last three columns of
Table 0.4.3.

##  0.5 Systematic uncertainties

Several sources of uncertainty are considered that affect either the
simulation of the background processes or the underlying theoretical modeling.
We distinguish between two types of uncertainties, ones that only affect the
normalization of a process and others that additionally affect the shape of
the distribution. All of these uncertainties are included in the global
simultaneous fit, described in detail later. The largest impacts on the final
results stem from the uncertainties in the tagging scale factors and the
limited statistical precision of the dilepton CR, where the latter is the main
determining factor for the contribution of events in the SL SRs.

The following sources of uncertainty correspond to constrained normalization
nuisance parameters in the fit (unless specified, the source of uncertainty
applies to all search channels):

  * •

Lepton reconstruction, selection, and trigger. Scale factors are applied to
the simulation in order to mimic the measured lepton reconstruction and
selection efficiencies in data. The measured uncertainties in these scale
factors are of the order of 2.2% per electron and 1% per muon, and are and
$\eta$ dependent [52, 53]. The effect of these uncertainties is found to be
independent of the spectrum.

  * •

trigger. At values of $\ptmiss>250\GeV$ the applied triggers are almost fully
efficient; a normalization uncertainty of 2% is assigned. This uncertainty is
only applied in the AH channel.

  * •

tagging efficiency scale factors. The tagging and light-flavor mistag
efficiencies scale factors and the respective uncertainties are measured in
independent control samples [30], and propagated to the analysis. In the range
of considered, these scale factor uncertainties do not alter the shape of the
distribution.

  * •

Forward jets. Inclusive CRs in terms of forward jet multiplicity are
considered to constrain the major background in the 0 and ${\geq}1$ forward
jets SRs. The impact of this extrapolation in forward jets multiplicity on the
background estimation is evaluated and assigned as additional systematic
uncertainty. The extrapolation effect is evaluated by splitting each CR into a
0f and 1f category, and a systematic uncertainty is assigned based on the
ratio of the correction factors, where each correction factor is the ratio of
the data to the simulation in its category. This uncertainty ranges from
approximately 2% ($\PW$+jets AH) to about 7% (SL).

  * •

Pileup modeling. Systematic uncertainties due to pileup modeling are taken
into account by varying the total inelastic cross section used to calculate
pileup distributions in simulation by $\pm$4.6% [55].

  * •

Luminosity. An uncertainty of 2.5% is taken on the integrated luminosity of
the data sample [56].

  * •

QCD multijet background normalization. An uncertainty of 100% in the
normalization is considered for QCD processes to cover effects in the
kinematic tails that may not be well-modeled by the simulation. This has
little overall impact on the final result, since the contribution from QCD
multijet events is reduced to a negligible amount in this analysis.

  * •

Single top quark background normalization. An uncertainty of 20% in the
normalization is considered for single top quark processes, accounting for the
uncertainty in the PDF and the effects from varying the factorization and
renormalization scale parameters.

  * •

Uncertainty related to ECAL mistiming. Partial mistiming of signals in the
forward regions of the ECAL endcaps led to a minor reduction in trigger
efficiency. To cover this effect, an additional uncertainty is applied on the
signal acceptances of up to 10% in the forward jet categories. A potential
effect on the background extrapolation into regions with forward jets is
already taken into account by a dedicated systematic uncertainty.

The following sources of uncertainty affect the shape of the distribution, as
well as the normalization of the various backgrounds and the signal, and are
applied to all search channels:

  * •

Jet energy scale. Reconstructed jet four-momenta in the simulation are varied
according to the uncertainty in the jet energy scale. Jet energy scale
uncertainties are coherently propagated to all observables, including [57].

  * •

PDF uncertainties. Uncertainties due to the choice of PDF are estimated by
reweighting the samples with the NNPDF3.0 [47] replicas [58] and are applied
to all backgrounds except for the single top quark, as these uncertainties are
covered by the associated background normalization uncertainty.

  * •

/+heavy-flavor fraction. The uncertainty in the fraction of /+heavy-flavor
(HF) jets in $\PW$+jets and $\PZ$+jets event is taken into account. The
relative contribution of +HF and +HF are allowed to vary within 20% [59, 60,
61, 62].

  * •

Electroweak and QCD $K$ factors. Uncertainties in the NLO/LO $K$ factors
calculated for $\PW$+jets and $\PZ$+jets processes are considered. These
uncertainties account for missing higher-order corrections. For QCD, this
comes from variations due to factorization and renormalization scales. For
electroweak processes, an estimate of the size of the missing higher-order
corrections is obtained by taking the difference between applying and not
applying the NLO/LO electroweak $K$ factors.

  * •

Top quark reweighting. Differential measurements of the top quark spectrum in
top quark pair production events [34] show that the measured spectrum is
softer than in simulation. In order to improve the description of top quark
pair events, simulated samples are reweighted to match the measurements. An
associated systematic uncertainty is estimated by taking the difference
between applying and not applying the reweighting.

  * •

Factorization and renormalization scales. The uncertainties in the choice of
the factorization and renormalization scale parameters are taken into account
for the , $\ttbar$+V, and diboson processes by applying a set of weights that
represent a change of these scales by a factor of 2 or 0.5.

  * •

Simulation sample size. Uncertainties due to the limited size of the simulated
signal and background samples are included by allowing each bin of the
distributions used in the signal extraction to fluctuate independently
according to the statistical uncertainties in simulation, following Ref. [63].

##  0.6 Signal extraction

As previously discussed, the potential DM signal is expected to have the
signature of or single top quark events with additional , therefore leading to
an excess of events above the SM prediction in the spectrum. The DM signal is
extracted from a simultaneous fit to the binned distribution in the various
SRs and CRs, including all previously mentioned uncertainties. This global fit
is performed as a binned maximum likelihood fit employing the RooStats
statistical package [64]. The main SM backgrounds were discussed previously in
Section 0.4, and are dileptonic $\ttbar$+jets and $\PW$+jets events for the SL
SRs, and ${\cPZ}\to\nu\nu$, single-lepton $\ttbar$+jets, and $\PW$+jets events
for the AH SRs.

The effect of the systematic uncertainties in the shape and normalization of
the spectrum, as discussed in the previous section, is taken into account by
introducing nuisance parameters, which are constrained by the magnitude of the
corresponding source of uncertainty. Uncertainties that affect normalization
only are modeled using nuisances with log-normal probability densities. These
parameters are treated as correlated between bins and between the different
CRs and SRs within each channel. The sources common between SL and AH SRs and
CRs are correlated across channels.

To improve the estimation of the main backgrounds, an unconstrained
multiplicative parameter is assigned separately to each background for each
bin of the spectrum. These multiplicative parameters scale the normalization
of the associated background process simultaneously in the SRs and CRs for a
given channel. For example, in a given bin of the SL selection, there is one
multiplicative parameter for that links the background in the enhanced 2$\ell$
CR, the $\PW$+jets enhanced 1$\ell$ CR, and the SR. Therefore, the effect of
contributions of the same background process in the different CRs is also
taken into account. Additionally, potential contributions from the DM signals
are included for all CRs and SRs, and scaled by a signal strength modifier
$\mu=\sigma/\sigma_{\text{th}}$, , the ratio between the measured and
theoretical cross sections. Regions containing leptons (electrons and muons)
are separated by lepton flavor.

The simultaneous fit to the binned distribution is performed combining the SL
and AH regions. The values for the background multiplicative factors extracted
from the fit are on average close to one, with a root-mean-square deviation
that ranges from 5% to 21%, depending on the background processes and on the
category considered (SL or AH). The post-fit distributions assuming the
absence from the DM signal (, the background only fit) are shown in Figs. 2
and 3 (4 and 5) for the SL and AH CRs (SRs), respectively. No significant
excess at high in the SRs is observed. The SRs, both for the SL and AH
channels, are divided into: 1 -tagged jet and 0 forward jets, 1 -tagged jet
and ${\geq}1$ forward jets, and ${\geq}2$ -tagged jets. The plots also contain
the pre-fit distributions, represented by the dashed magenta line. The
statistical and systematic uncertainties in the prediction are represented by
hatched uncertainty bands, while the lower panels show the ratio of data and
the post-fit prediction, and the bottom panels show the difference between the
observed data events and the post-fit total background, divided by the full
statistical and systematic uncertainty.

Figure 2: Background-only post-fit distributions for the CRs of the SL
selection. The total theory signal (${\cPqt}/\overline{{\cPqt}}$+DM and
$\ttbar$+DM summed together) is negligible and therefore is not shown. The
last bin contains overflow events. The dashed magenta lines show the total
pre-fit background expectation in the upper panels, and the ratio of pre-fit
total background to post-fit total background in the middle panels. The lower
panels show the difference between observed and post-fit total background
divided by the full statistical and systematic uncertainties.

Figure 3: Background-only post-fit distributions for the CRs of the AH
selection. The total theory signal (${\cPqt}/\overline{{\cPqt}}$+DM and
$\ttbar$+DM summed together) is negligible and therefore is not shown. The
last bin contains overflow events. The dashed magenta lines show the total
pre-fit background expectation in the upper panels, and the ratio of pre-fit
total background to post-fit total background in the middle panels. The lower
panels show the difference between observed and post-fit total background
divided by the full statistical and systematic uncertainties.

Figure 4: Background-only post-fit distributions for the SRs of the SL
selection. The total theory signal (${\cPqt}/\overline{{\cPqt}}$+DM and
$\ttbar$+DM summed together) is presented by the red solid lines for a scalar
mediator mass of 100. The last bin contains overflow events. The dashed
magenta lines show the total pre-fit background expectation in the upper
panels, and the ratio of pre-fit total background to post-fit total background
in the middle panels. The lower panels show the difference between observed
and post-fit total background divided by the full statistical and systematic
uncertainties.

Figure 5: Background-only post-fit distributions for the SRs of the AH
selection. The total theory signal (${\cPqt}/\overline{{\cPqt}}$+DM and
$\ttbar$+DM summed together) is presented by the red solid lines for a scalar
mediator mass of 100. The last bin contains overflow events. The dashed
magenta lines show the total pre-fit background expectation in the upper
panels, and the ratio of pre-fit total background to post-fit total background
in the middle panels. The lower panels show the difference between observed
and post-fit total background divided by the full statistical and systematic
uncertainties.

##  0.7 Results

Overall, data are found to be in agreement with the expected SM background in
the SRs. Upper limits at 95% confidence level () are computed on the ratio
between the measured and theoretical cross sections $\mu$, which is calculated
with respect to the expected number of events for a scalar or pseudoscalar
mediator and either the ${\cPqt}/\overline{{\cPqt}}$+DM or $\ttbar$+DM
production modes separately, or summed together, where the results are
referred to here as ${\cPqt}$, $\ttbar$+DM. The theoretical cross sections for
both signal models are obtained at LO. The limits are calculated using a
modified frequentist approach with a test statistic based on the profile
likelihood in the asymptotic approximation and the criterion [65, 66, 67]. We
test different mediator mass scenarios with ${m}_{\chi}=1\GeV$ and
$g_{\cPq}=g_{\chi}=1$ and the results are shown in Fig. 6 for scalar (left)
and pseudoscalar (right) models. The expected limit for the
${\cPqt}/\overline{{\cPqt}}$+DM signal alone is depicted by the blue dash-
dotted line, while the expected $\ttbar$+DM limit alone is given by the red
dash-dotted line. The observed limit on the sum of both signals is represented
by the black solid line, while its expected value is shown by the black dashed
line with the 68 and 95% uncertainty bands in green and yellow, respectively.

For masses of the mediator particle below 200for the scalar model and below
300for the pseudoscalar model, the leading contribution to the sensitivity of
the analysis stems from $\ttbar$+DM. This behavior is mostly driven by the
larger cross section for the $\ttbar$+DM process when compared to the sum of
the production processes for ${\cPqt}/\overline{{\cPqt}}$+DM. However, the
${\cPqt}/\overline{{\cPqt}}$+DM cross section drops less rapidly as a function
of mediator particle mass in comparison to the $\ttbar$+DM mode. Additionally,
the spectrum for a given mediator mass leans towards higher values for the
${\cPqt}/\overline{{\cPqt}}$+DM signal model when compared to the $\ttbar$+DM
model. These two features, together with the analysis specifically designed
for both DM production modes and the statistical combination of the different
SRs, lead up to a factor of two improvement at high mediator masses on the
limits when compared to previous results [16]. In particular, the ${\geq}1$
forward jet category, which is specifically designed to enhance
${\cPqt}/\overline{{\cPqt}}$+DM $t$ channel events, improves the final results
up to 14%.

Figure 6:  The expected and observed 95% limits on the DM production cross
sections, relative to the theory predictions, shown for the scalar (left) and
pseudoscalar (right) models. The expected limit for the
${\cPqt}/\overline{{\cPqt}}$+DM signal alone is depicted by the blue dash-
dotted line, while the $\ttbar$+DM limit alone is given by the red dash-dotted
line. The observed limit on the sum of both signals is shown by the black
solid line, while the expected value is shown by the black dashed line with
the 68 and 95% uncertainty bands in green and yellow, respectively. The solid
horizontal line corresponds to $\sigma/\sigma_{\text{th}}=1$.

Table 0.7 represents the final combined limits (SL + AH) for the
${\cPqt}/\overline{{\cPqt}}$+DM and $\ttbar$+DM processes separately, and for
the sum of the two processes.

Overall, we exclude mediator masses below 290 and 300for the scalar and
pseudoscalar hypotheses, respectively.

Upper limits at 95% on the cross section ratio with respect to the expected DM
signal for different scalar ($\phi$) or pseudoscalar () mediator masses,
${m}_{\chi}=1\GeV$, and $g_{\chi}=g_{\cPq}=1$ for the combination of SL and AH
signal regions. The median expected value and its 68 and 95% confidence
intervals (CIs) are given.  ${\cPqt}/\overline{{\cPqt}}$+DM $\ttbar$+DM
${\cPqt}$, $\ttbar$+DM sum ${m}_{\phi/\Pa}$() Obs. Exp. Obs. Exp. Obs. Exp.
68% CI 95% CI Scalar 10 1.59 1.12 0.91 0.50 0.62 0.39
$\left[0.27,\>0.55\right]$ $\left[0.21,\>0.76\right]$ 20 1.38 1.04 0.84 0.52
0.58 0.39 $\left[0.28,\>0.56\right]$ $\left[0.21,\>0.77\right]$ 50 1.15 1.13
1.11 0.72 0.59 0.46 $\left[0.33,\>0.66\right]$ $\left[0.25,\>0.90\right]$ 100
1.43 1.23 0.94 0.96 0.60 0.57 $\left[0.41,\>0.81\right]$
$\left[0.30,\>1.11\right]$ 200 1.66 1.57 1.37 1.46 0.78 0.79
$\left[0.56,\>1.11\right]$ $\left[0.42,\>1.51\right]$ 300 1.97 2.02 2.09 2.40
1.05 1.13 $\left[0.81,\>1.60\right]$ $\left[0.60,\>2.17\right]$ 500 5.84 5.67
7.48 8.97 3.39 3.59 $\left[2.57,\>5.07\right]$ $\left[1.91,\>6.88\right]$
Pseudoscalar 10 1.43 1.31 0.70 0.70 0.49 0.47 $\left[0.34,\>0.67\right]$
$\left[0.25,\>0.92\right]$ 20 1.43 1.28 0.71 0.75 0.49 0.49
$\left[0.35,\>0.70\right]$ $\left[0.26,\>0.95\right]$ 50 1.48 1.35 0.70 0.73
0.49 0.50 $\left[0.35,\>0.70\right]$ $\left[0.26,\>0.96\right]$ 100 1.53 1.43
0.81 0.84 0.55 0.55 $\left[0.39,\>0.78\right]$ $\left[0.29,\>1.06\right]$ 200
1.89 1.73 1.18 1.16 0.76 0.72 $\left[0.52,\>1.02\right]$
$\left[0.38,\>1.38\right]$ 300 2.17 2.17 1.74 1.85 1.00 1.04
$\left[0.74,\>1.47\right]$ $\left[0.55,\>2.00\right]$ 500 8.22 8.31 8.00 9.25
4.17 4.53 $\left[3.24,\>6.39\right]$ $\left[2.41,\>8.67\right]$

##  0.8 Summary

The first search at the LHC for dark matter (DM) produced in association with
a single top quark or a top quark pair in interactions mediated by a neutral
scalar or pseudoscalar particle in proton-proton collisions at a center-of-
mass energy of 13has been presented. The data correspond to an integrated
luminosity of 35.9recorded by the CMS experiment in 2016. No significant
deviations with respect to standard model predictions are observed and the
results are interpreted in the context of a simplified model in which a scalar
or pseudoscalar mediator particle couples to the top quark and subsequently
decays into two DM particles.

Scalar and pseudoscalar mediator masses below 290 and 300are excluded at 95%
confidence level assuming a DM particle mass of 1and mediator couplings to
fermions and DM particles equal to unity. This analysis provides the most
stringent limits derived at the LHC for these new spin-0 mediator particles.

###### Acknowledgements.

We congratulate our colleagues in the CERN accelerator departments for the
excellent performance of the LHC and thank the technical and administrative
staffs at CERN and at other CMS institutes for their contributions to the
success of the CMS effort. In addition, we gratefully acknowledge the
computing centres and personnel of the Worldwide LHC Computing Grid for
delivering so effectively the computing infrastructure essential to our
analyses. Finally, we acknowledge the enduring support for the construction
and operation of the LHC and the CMS detector provided by the following
funding agencies: BMBWF and FWF (Austria); FNRS and FWO (Belgium); CNPq,
CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST,
and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF
(Cyprus); SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of
Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and
HGF (Germany); GSRT (Greece); NKFIA (Hungary); DAE and DST (India); IPM
(Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES
(Latvia); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT,
LNS, SEP, and UASLP-FAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC
(Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom,
RAS, RFBR, and NRC KI (Russia); MESTD (Serbia); SEIDI, CPAN, PCTI, and FEDER
(Spain); MOSTR (Sri Lanka); Swiss Funding Agencies (Switzerland); MST
(Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK
(Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA).
Individuals have received support from the Marie-Curie programme and the
European Research Council and Horizon 2020 Grant, contract No. 675440
(European Union); the Leventis Foundation; the A.P. Sloan Foundation; the
Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office;
the Fonds pour la Formation à la Recherche dans l’Industrie et dans
l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en
Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the
“Excellence of Science – EOS” – be.h project n. 30820817; the Ministry of
Education, Youth and Sports (MEYS) of the Czech Republic; the Lendület
(“Momentum”) Programme and the János Bolyai Research Scholarship of the
Hungarian Academy of Sciences, the New National Excellence Program ÚNKP, the
NKFIA research grants 123842, 123959, 124845, 124850, and 125105 (Hungary);
the Council of Science and Industrial Research, India; the HOMING PLUS
programme of the Foundation for Polish Science, cofinanced from European
Union, Regional Development Fund, the Mobility Plus programme of the Ministry
of Science and Higher Education, the National Science Center (Poland),
contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543,
2014/15/B/ST2/03998, and 2015/19/B/ST2/02861, Sonata-bis 2012/07/E/ST2/01406;
the National Priorities Research Program by Qatar National Research Fund; the
Programa Estatal de Fomento de la Investigación Científica y Técnica de
Excelencia María de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa
del Principado de Asturias; the Thalis and Aristeia programmes cofinanced by
EU-ESF and the Greek NSRF; the Rachadapisek Sompot Fund for Postdoctoral
Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its
2nd Century Project Advancement Project (Thailand); the Welch Foundation,
contract C-1845; and the Weston Havens Foundation (USA).

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##  .9 The CMS Collaboration

Yerevan Physics Institute, Yerevan, Armenia
A.M. Sirunyan, A. Tumasyan Institut für Hochenergiephysik, Wien, Austria
W. Adam, F. Ambrogi, E. Asilar, T. Bergauer, J. Brandstetter, M. Dragicevic,
J. Erö, A. Escalante Del Valle, M. Flechl, R. Frühwirth1, V.M. Ghete, J.
Hrubec, M. Jeitler1, N. Krammer, I. Krätschmer, D. Liko, T. Madlener, I.
Mikulec, N. Rad, H. Rohringer, J. Schieck1, R. Schöfbeck, M. Spanring, D.
Spitzbart, W. Waltenberger, J. Wittmann, C.-E. Wulz1, M. Zarucki Institute for
Nuclear Problems, Minsk, Belarus
V. Chekhovsky, V. Mossolov, J. Suarez Gonzalez Universiteit Antwerpen,
Antwerpen, Belgium
E.A. De Wolf, D. Di Croce, X. Janssen, J. Lauwers, M. Pieters, H. Van
Haevermaet, P. Van Mechelen, N. Van Remortel Vrije Universiteit Brussel,
Brussel, Belgium
S. Abu Zeid, F. Blekman, J. D’Hondt, J. De Clercq, K. Deroover, G. Flouris, D.
Lontkovskyi, S. Lowette, I. Marchesini, S. Moortgat, L. Moreels, Q. Python, K.
Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders, I. Van Parijs
Université Libre de Bruxelles, Bruxelles, Belgium
D. Beghin, B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B.
Dorney, G. Fasanella, L. Favart, R. Goldouzian, A. Grebenyuk, A.K. Kalsi, T.
Lenzi, J. Luetic, N. Postiau, E. Starling, L. Thomas, C. Vander Velde, P.
Vanlaer, D. Vannerom, Q. Wang Ghent University, Ghent, Belgium
T. Cornelis, D. Dobur, A. Fagot, M. Gul, I. Khvastunov2, D. Poyraz, C. Roskas,
D. Trocino, M. Tytgat, W. Verbeke, B. Vermassen, M. Vit, N. Zaganidis
Université Catholique de Louvain, Louvain-la-Neuve, Belgium
H. Bakhshiansohi, O. Bondu, S. Brochet, G. Bruno, C. Caputo, P. David, C.
Delaere, M. Delcourt, A. Giammanco, G. Krintiras, V. Lemaitre, A. Magitteri,
K. Piotrzkowski, A. Saggio, M. Vidal Marono, P. Vischia, S. Wertz, J. Zobec
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil
F.L. Alves, G.A. Alves, M. Correa Martins Junior, G. Correia Silva, C. Hensel,
A. Moraes, M.E. Pol, P. Rebello Teles Universidade do Estado do Rio de
Janeiro, Rio de Janeiro, Brazil
E. Belchior Batista Das Chagas, W. Carvalho, J. Chinellato3, E. Coelho, E.M.
Da Costa, G.G. Da Silveira4, D. De Jesus Damiao, C. De Oliveira Martins, S.
Fonseca De Souza, H. Malbouisson, D. Matos Figueiredo, M. Melo De Almeida, C.
Mora Herrera, L. Mundim, H. Nogima, W.L. Prado Da Silva, L.J. Sanchez Rosas,
A. Santoro, A. Sznajder, M. Thiel, E.J. Tonelli Manganote3, F. Torres Da Silva
De Araujo, A. Vilela Pereira Universidade Estadual Paulista a, Universidade
Federal do ABC b, São Paulo, Brazil
S. Ahujaa, C.A. Bernardesa, L. Calligarisa, T.R. Fernandez Perez Tomeia, E.M.
Gregoresb, P.G. Mercadanteb, S.F. Novaesa, SandraS. Padulaa Institute for
Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia,
Bulgaria
A. Aleksandrov, R. Hadjiiska, P. Iaydjiev, A. Marinov, M. Misheva, M. Rodozov,
M. Shopova, G. Sultanov University of Sofia, Sofia, Bulgaria
A. Dimitrov, L. Litov, B. Pavlov, P. Petkov Beihang University, Beijing, China
W. Fang5, X. Gao5, L. Yuan Institute of High Energy Physics, Beijing, China
M. Ahmad, J.G. Bian, G.M. Chen, H.S. Chen, M. Chen, Y. Chen, C.H. Jiang, D.
Leggat, H. Liao, Z. Liu, S.M. Shaheen6, A. Spiezia, J. Tao, Z. Wang, E.
Yazgan, H. Zhang, S. Zhang6, J. Zhao State Key Laboratory of Nuclear Physics
and Technology, Peking University, Beijing, China
Y. Ban, G. Chen, A. Levin, J. Li, L. Li, Q. Li, Y. Mao, S.J. Qian, D. Wang
Tsinghua University, Beijing, China
Y. Wang Universidad de Los Andes, Bogota, Colombia
C. Avila, A. Cabrera, C.A. Carrillo Montoya, L.F. Chaparro Sierra, C. Florez,
C.F. González Hernández, M.A. Segura Delgado University of Split, Faculty of
Electrical Engineering, Mechanical Engineering and Naval Architecture, Split,
Croatia
B. Courbon, N. Godinovic, D. Lelas, I. Puljak, T. Sculac University of Split,
Faculty of Science, Split, Croatia
Z. Antunovic, M. Kovac Institute Rudjer Boskovic, Zagreb, Croatia
V. Brigljevic, D. Ferencek, K. Kadija, B. Mesic, A. Starodumov7, T. Susa
University of Cyprus, Nicosia, Cyprus
M.W. Ather, A. Attikis, M. Kolosova, G. Mavromanolakis, J. Mousa, C. Nicolaou,
F. Ptochos, P.A. Razis, H. Rykaczewski Charles University, Prague, Czech
Republic
M. Finger8, M. Finger Jr.8 Escuela Politecnica Nacional, Quito, Ecuador
E. Ayala Universidad San Francisco de Quito, Quito, Ecuador
E. Carrera Jarrin Academy of Scientific Research and Technology of the Arab
Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt
S. Elgammal9, A. Ellithi Kamel10, E. Salama9,11 National Institute of Chemical
Physics and Biophysics, Tallinn, Estonia
S. Bhowmik, A. Carvalho Antunes De Oliveira, R.K. Dewanjee, K. Ehataht, M.
Kadastik, M. Raidal, C. Veelken Department of Physics, University of Helsinki,
Helsinki, Finland
P. Eerola, H. Kirschenmann, J. Pekkanen, M. Voutilainen Helsinki Institute of
Physics, Helsinki, Finland
J. Havukainen, J.K. Heikkilä, T. Järvinen, V. Karimäki, R. Kinnunen, T.
Lampén, K. Lassila-Perini, S. Laurila, S. Lehti, T. Lindén, P. Luukka, T.
Mäenpää, H. Siikonen, E. Tuominen, J. Tuominiemi Lappeenranta University of
Technology, Lappeenranta, Finland
T. Tuuva IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
M. Besancon, F. Couderc, M. Dejardin, D. Denegri, J.L. Faure, F. Ferri, S.
Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, C. Leloup,
E. Locci, J. Malcles, G. Negro, J. Rander, A. Rosowsky, M.Ö. Sahin, M. Titov
Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Université
Paris-Saclay, Palaiseau, France
A. Abdulsalam12, C. Amendola, I. Antropov, F. Beaudette, P. Busson, C.
Charlot, R. Granier de Cassagnac, I. Kucher, A. Lobanov, J. Martin Blanco, C.
Martin Perez, M. Nguyen, C. Ochando, G. Ortona, P. Paganini, P. Pigard, J.
Rembser, R. Salerno, J.B. Sauvan, Y. Sirois, A.G. Stahl Leiton, A. Zabi, A.
Zghiche Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
J.-L. Agram13, J. Andrea, D. Bloch, J.-M. Brom, E.C. Chabert, V. Cherepanov,
C. Collard, E. Conte13, J.-C. Fontaine13, D. Gelé, U. Goerlach, M. Jansová,
A.-C. Le Bihan, N. Tonon, P. Van Hove Centre de Calcul de l’Institut National
de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3, Villeurbanne,
France
S. Gadrat Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3,
Institut de Physique Nucléaire de Lyon, Villeurbanne, France
S. Beauceron, C. Bernet, G. Boudoul, N. Chanon, R. Chierici, D. Contardo, P.
Depasse, H. El Mamouni, J. Fay, L. Finco, S. Gascon, M. Gouzevitch, G.
Grenier, B. Ille, F. Lagarde, I.B. Laktineh, H. Lattaud, M. Lethuillier, L.
Mirabito, S. Perries, A. Popov14, V. Sordini, G. Touquet, M. Vander Donckt, S.
Viret Georgian Technical University, Tbilisi, Georgia
A. Khvedelidze8 Tbilisi State University, Tbilisi, Georgia
I. Bagaturia15 RWTH Aachen University, I. Physikalisches Institut, Aachen,
Germany
C. Autermann, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, M. Preuten, M.P.
Rauch, C. Schomakers, J. Schulz, M. Teroerde, B. Wittmer RWTH Aachen
University, III. Physikalisches Institut A, Aachen, Germany
A. Albert, D. Duchardt, M. Erdmann, S. Erdweg, T. Esch, R. Fischer, S. Ghosh,
A. Güth, T. Hebbeker, C. Heidemann, K. Hoepfner, H. Keller, L. Mastrolorenzo,
M. Merschmeyer, A. Meyer, P. Millet, S. Mukherjee, T. Pook, M. Radziej, H.
Reithler, M. Rieger, A. Schmidt, D. Teyssier, S. Thüer RWTH Aachen University,
III. Physikalisches Institut B, Aachen, Germany
G. Flügge, O. Hlushchenko, T. Kress, T. Müller, A. Nehrkorn, A. Nowack, C.
Pistone, O. Pooth, D. Roy, H. Sert, A. Stahl16 Deutsches Elektronen-
Synchrotron, Hamburg, Germany
M. Aldaya Martin, T. Arndt, C. Asawatangtrakuldee, I. Babounikau, K.
Beernaert, O. Behnke, U. Behrens, A. Bermúdez Martínez, D. Bertsche, A.A. Bin
Anuar, K. Borras17, V. Botta, A. Campbell, P. Connor, C. Contreras-Campana, V.
Danilov, A. De Wit, M.M. Defranchis, C. Diez Pardos, D. Domínguez Damiani, G.
Eckerlin, T. Eichhorn, A. Elwood, E. Eren, E. Gallo18, A. Geiser, J.M. Grados
Luyando, A. Grohsjean, M. Guthoff, M. Haranko, A. Harb, H. Jung, M. Kasemann,
J. Keaveney, C. Kleinwort, J. Knolle, D. Krücker, W. Lange, A. Lelek, T. Lenz,
J. Leonard, K. Lipka, W. Lohmann19, R. Mankel, I.-A. Melzer-Pellmann, A.B.
Meyer, M. Meyer, M. Missiroli, J. Mnich, V. Myronenko, S.K. Pflitsch, D.
Pitzl, A. Raspereza, P. Saxena, P. Schütze, C. Schwanenberger, R. Shevchenko,
A. Singh, H. Tholen, O. Turkot, A. Vagnerini, G.P. Van Onsem, R. Walsh, Y.
Wen, K. Wichmann, C. Wissing, O. Zenaiev University of Hamburg, Hamburg,
Germany
R. Aggleton, S. Bein, L. Benato, A. Benecke, V. Blobel, T. Dreyer, A.
Ebrahimi, E. Garutti, D. Gonzalez, P. Gunnellini, J. Haller, A. Hinzmann, A.
Karavdina, G. Kasieczka, R. Klanner, R. Kogler, N. Kovalchuk, S. Kurz, V.
Kutzner, J. Lange, D. Marconi, J. Multhaup, M. Niedziela, C.E.N. Niemeyer, D.
Nowatschin, A. Perieanu, A. Reimers, O. Rieger, C. Scharf, P. Schleper, S.
Schumann, J. Schwandt, J. Sonneveld, H. Stadie, G. Steinbrück, F.M. Stober, M.
Stöver, B. Vormwald, I. Zoi Karlsruher Institut fuer Technologie, Karlsruhe,
Germany
M. Akbiyik, C. Barth, M. Baselga, S. Baur, E. Butz, R. Caspart, T. Chwalek, F.
Colombo, W. De Boer, A. Dierlamm, K. El Morabit, N. Faltermann, B. Freund, M.
Giffels, M.A. Harrendorf, F. Hartmann16, S.M. Heindl, U. Husemann, I.
Katkov14, S. Kudella, S. Mitra, M.U. Mozer, Th. Müller, M. Musich, M. Plagge,
G. Quast, K. Rabbertz, M. Schröder, I. Shvetsov, H.J. Simonis, R. Ulrich, S.
Wayand, M. Weber, T. Weiler, C. Wöhrmann, R. Wolf Institute of Nuclear and
Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece
G. Anagnostou, G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas, G. Paspalaki
National and Kapodistrian University of Athens, Athens, Greece
A. Agapitos, G. Karathanasis, P. Kontaxakis, A. Panagiotou, I. Papavergou, N.
Saoulidou, E. Tziaferi, K. Vellidis National Technical University of Athens,
Athens, Greece
K. Kousouris, I. Papakrivopoulos, G. Tsipolitis University of Ioánnina,
Ioánnina, Greece
I. Evangelou, C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios, N.
Manthos, I. Papadopoulos, E. Paradas, J. Strologas, F.A. Triantis, D.
Tsitsonis MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
M. Bartók20, M. Csanad, N. Filipovic, P. Major, M.I. Nagy, G. Pasztor, O.
Surányi, G.I. Veres Wigner Research Centre for Physics, Budapest, Hungary
G. Bencze, C. Hajdu, D. Horvath21, Á. Hunyadi, F. Sikler, T.Á. Vámi, V.
Veszpremi, G. Vesztergombi${}^{\textrm{\textdagger}}$ Institute of Nuclear
Research ATOMKI, Debrecen, Hungary
N. Beni, S. Czellar, J. Karancsi20, A. Makovec, J. Molnar, Z. Szillasi
Institute of Physics, University of Debrecen, Debrecen, Hungary
P. Raics, Z.L. Trocsanyi, B. Ujvari Indian Institute of Science (IISc),
Bangalore, India
S. Choudhury, J.R. Komaragiri, P.C. Tiwari National Institute of Science
Education and Research, HBNI, Bhubaneswar, India
S. Bahinipati23, C. Kar, P. Mal, K. Mandal, A. Nayak24, S. Roy Chowdhury, D.K.
Sahoo23, S.K. Swain Panjab University, Chandigarh, India
S. Bansal, S.B. Beri, V. Bhatnagar, S. Chauhan, R. Chawla, N. Dhingra, R.
Gupta, A. Kaur, M. Kaur, S. Kaur, P. Kumari, M. Lohan, M. Meena, A. Mehta, K.
Sandeep, S. Sharma, J.B. Singh, A.K. Virdi, G. Walia University of Delhi,
Delhi, India
A. Bhardwaj, B.C. Choudhary, R.B. Garg, M. Gola, S. Keshri, Ashok Kumar, S.
Malhotra, M. Naimuddin, P. Priyanka, K. Ranjan, Aashaq Shah, R. Sharma Saha
Institute of Nuclear Physics, HBNI, Kolkata, India
R. Bhardwaj25, M. Bharti25, R. Bhattacharya, S. Bhattacharya, U. Bhawandeep25,
D. Bhowmik, S. Dey, S. Dutt25, S. Dutta, S. Ghosh, K. Mondal, S. Nandan, A.
Purohit, P.K. Rout, A. Roy, G. Saha, S. Sarkar, M. Sharan, B. Singh25, S.
Thakur25 Indian Institute of Technology Madras, Madras, India
P.K. Behera, A. Muhammad Bhabha Atomic Research Centre, Mumbai, India
R. Chudasama, D. Dutta, V. Jha, V. Kumar, D.K. Mishra, P.K. Netrakanti, L.M.
Pant, P. Shukla Tata Institute of Fundamental Research-A, Mumbai, India
T. Aziz, M.A. Bhat, S. Dugad, G.B. Mohanty, N. Sur, B. Sutar, RavindraKumar
Verma Tata Institute of Fundamental Research-B, Mumbai, India
S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, Sa. Jain, S.
Karmakar, S. Kumar, M. Maity26, G. Majumder, K. Mazumdar, N. Sahoo, T.
Sarkar26 Indian Institute of Science Education and Research (IISER), Pune,
India
S. Chauhan, S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, A.
Rastogi, S. Sharma Institute for Research in Fundamental Sciences (IPM),
Tehran, Iran
S. Chenarani27, E. Eskandari Tadavani, S.M. Etesami27, M. Khakzad, M.
Mohammadi Najafabadi, M. Naseri, F. Rezaei Hosseinabadi, B. Safarzadeh28, M.
Zeinali University College Dublin, Dublin, Ireland
M. Felcini, M. Grunewald INFN Sezione di Bari a, Università di Bari b,
Politecnico di Bari c, Bari, Italy
M. Abbresciaa,b, C. Calabriaa,b, A. Colaleoa, D. Creanzaa,c, L. Cristellaa,b,
N. De Filippisa,c, M. De Palmaa,b, A. Di Florioa,b, F. Erricoa,b, L. Fiorea,
A. Gelmia,b, G. Iasellia,c, M. Incea,b, S. Lezkia,b, G. Maggia,c, M. Maggia,
G. Minielloa,b, S. Mya,b, S. Nuzzoa,b, A. Pompilia,b, G. Pugliesea,c, R.
Radognaa, A. Ranieria, G. Selvaggia,b, A. Sharmaa, L. Silvestrisa, R.
Vendittia, P. Verwilligena INFN Sezione di Bologna a, Università di Bologna b,
Bologna, Italy
G. Abbiendia, C. Battilanaa,b, D. Bonacorsia,b, L. Borgonovia,b, S. Braibant-
Giacomellia,b, R. Campaninia,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa,
S.S. Chhibraa,b, G. Codispotia,b, M. Cuffiania,b, G.M. Dallavallea, F.
Fabbria, A. Fanfania,b, E. Fontanesi, P. Giacomellia, C. Grandia, L.
Guiduccia,b, F. Iemmia,b, S. Lo Meoa, S. Marcellinia, G. Masettia, A.
Montanaria, F.L. Navarriaa,b, A. Perrottaa, F. Primaveraa,b,16, A.M. Rossia,b,
T. Rovellia,b, G.P. Sirolia,b, N. Tosia INFN Sezione di Catania a, Università
di Catania b, Catania, Italy
S. Albergoa,b, A. Di Mattiaa, R. Potenzaa,b, A. Tricomia,b, C. Tuvea,b INFN
Sezione di Firenze a, Università di Firenze b, Firenze, Italy
G. Barbaglia, K. Chatterjeea,b, V. Ciullia,b, C. Civininia, R.
D’Alessandroa,b, E. Focardia,b, G. Latino, P. Lenzia,b, M. Meschinia, S.
Paolettia, L. Russoa,29, G. Sguazzonia, D. Stroma, L. Viliania INFN Laboratori
Nazionali di Frascati, Frascati, Italy
L. Benussi, S. Bianco, F. Fabbri, D. Piccolo INFN Sezione di Genova a,
Università di Genova b, Genova, Italy
F. Ferroa, R. Mulargiaa,b, F. Raveraa,b, E. Robuttia, S. Tosia,b INFN Sezione
di Milano-Bicocca a, Università di Milano-Bicocca b, Milano, Italy
A. Benagliaa, A. Beschib, F. Brivioa,b, V. Cirioloa,b,16, S. Di Guidaa,b,16,
M.E. Dinardoa,b, S. Fiorendia,b, S. Gennaia, A. Ghezzia,b, P. Govonia,b, M.
Malbertia,b, S. Malvezzia, D. Menascea, F. Monti, L. Moronia, M. Paganonia,b,
D. Pedrinia, S. Ragazzia,b, T. Tabarelli de Fatisa,b, D. Zuoloa,b INFN Sezione
di Napoli a, Università di Napoli ’Federico II’ b, Napoli, Italy, Università
della Basilicata c, Potenza, Italy, Università G. Marconi d, Roma, Italy
S. Buontempoa, N. Cavalloa,c, A. De Iorioa,b, A. Di Crescenzoa,b, F.
Fabozzia,c, F. Fiengaa, G. Galatia, A.O.M. Iorioa,b, W.A. Khana, L. Listaa, S.
Meolaa,d,16, P. Paoluccia,16, C. Sciaccaa,b, E. Voevodinaa,b INFN Sezione di
Padova a, Università di Padova b, Padova, Italy, Università di Trento c,
Trento, Italy
P. Azzia, N. Bacchettaa, D. Biselloa,b, A. Bolettia,b, A. Bragagnolo, R.
Carlina,b, P. Checchiaa, M. Dall’Ossoa,b, P. De Castro Manzanoa, T. Dorigoa,
U. Dossellia, F. Gasparinia,b, U. Gasparinia,b, A. Gozzelinoa, S.Y. Hoh, S.
Lacapraraa, P. Lujan, M. Margonia,b, A.T. Meneguzzoa,b, J. Pazzinia,b, M.
Presillab, P. Ronchesea,b, R. Rossina,b, F. Simonettoa,b, A. Tiko, E.
Torassaa, M. Tosia,b, M. Zanettia,b, P. Zottoa,b, G. Zumerlea,b INFN Sezione
di Pavia a, Università di Pavia b, Pavia, Italy
A. Braghieria, A. Magnania, P. Montagnaa,b, S.P. Rattia,b, V. Rea, M.
Ressegottia,b, C. Riccardia,b, P. Salvinia, I. Vaia,b, P. Vituloa,b INFN
Sezione di Perugia a, Università di Perugia b, Perugia, Italy
M. Biasinia,b, G.M. Bileia, C. Cecchia,b, D. Ciangottinia,b, L. Fanòa,b, P.
Laricciaa,b, R. Leonardia,b, E. Manonia, G. Mantovania,b, V. Mariania,b, M.
Menichellia, A. Rossia,b, A. Santocchiaa,b, D. Spigaa INFN Sezione di Pisa a,
Università di Pisa b, Scuola Normale Superiore di Pisa c, Pisa, Italy
K. Androsova, P. Azzurria, G. Bagliesia, L. Bianchinia, T. Boccalia, L.
Borrello, R. Castaldia, M.A. Cioccia,b, R. Dell’Orsoa, G. Fedia, F. Fioria,c,
L. Gianninia,c, A. Giassia, M.T. Grippoa, F. Ligabuea,c, E. Mancaa,c, G.
Mandorlia,c, A. Messineoa,b, F. Pallaa, A. Rizzia,b, G. Rolandi30, P.
Spagnoloa, R. Tenchinia, G. Tonellia,b, A. Venturia, P.G. Verdinia INFN
Sezione di Roma a, Sapienza Università di Roma b, Rome, Italy
L. Baronea,b, F. Cavallaria, M. Cipriania,b, D. Del Rea,b, E. Di Marcoa,b, M.
Diemoza, S. Gellia,b, E. Longoa,b, B. Marzocchia,b, P. Meridiania, G.
Organtinia,b, F. Pandolfia, R. Paramattia,b, F. Preiatoa,b, S. Rahatloua,b, C.
Rovellia, F. Santanastasioa,b INFN Sezione di Torino a, Università di Torino
b, Torino, Italy, Università del Piemonte Orientale c, Novara, Italy
N. Amapanea,b, R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c, N. Bartosika,
R. Bellana,b, C. Biinoa, A. Cappatia,b, N. Cartigliaa, F. Cennaa,b, S.
Comettia, M. Costaa,b, R. Covarellia,b, N. Demariaa, B. Kiania,b, C.
Mariottia, S. Masellia, E. Migliorea,b, V. Monacoa,b, E. Monteila,b, M.
Montenoa, M.M. Obertinoa,b, L. Pachera,b, N. Pastronea, M. Pelliccionia, G.L.
Pinna Angionia,b, A. Romeroa,b, M. Ruspaa,c, R. Sacchia,b, R. Salvaticoa,b, K.
Shchelinaa,b, V. Solaa, A. Solanoa,b, D. Soldia,b, A. Staianoa INFN Sezione di
Trieste a, Università di Trieste b, Trieste, Italy
S. Belfortea, V. Candelisea,b, M. Casarsaa, F. Cossuttia, A. Da Rolda,b, G.
Della Riccaa,b, F. Vazzolera,b, A. Zanettia Kyungpook National University,
Daegu, Korea
D.H. Kim, G.N. Kim, M.S. Kim, J. Lee, S. Lee, S.W. Lee, C.S. Moon, Y.D. Oh,
S.I. Pak, S. Sekmen, D.C. Son, Y.C. Yang Chonnam National University,
Institute for Universe and Elementary Particles, Kwangju, Korea
H. Kim, D.H. Moon, G. Oh Hanyang University, Seoul, Korea
B. Francois, J. Goh31, T.J. Kim Korea University, Seoul, Korea
S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, Y. Jo, K. Lee, K.S. Lee, S.
Lee, J. Lim, S.K. Park, Y. Roh Sejong University, Seoul, Korea
H.S. Kim Seoul National University, Seoul, Korea
J. Almond, J. Kim, J.S. Kim, H. Lee, K. Lee, K. Nam, S.B. Oh, B.C. Radburn-
Smith, S.h. Seo, U.K. Yang, H.D. Yoo, G.B. Yu University of Seoul, Seoul,
Korea
D. Jeon, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park Sungkyunkwan University,
Suwon, Korea
Y. Choi, C. Hwang, J. Lee, I. Yu Vilnius University, Vilnius, Lithuania
V. Dudenas, A. Juodagalvis, J. Vaitkus National Centre for Particle Physics,
Universiti Malaya, Kuala Lumpur, Malaysia
I. Ahmed, Z.A. Ibrahim, M.A.B. Md Ali32, F. Mohamad Idris33, W.A.T. Wan
Abdullah, M.N. Yusli, Z. Zolkapli Universidad de Sonora (UNISON), Hermosillo,
Mexico
J.F. Benitez, A. Castaneda Hernandez, J.A. Murillo Quijada Centro de
Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
H. Castilla-Valdez, E. De La Cruz-Burelo, M.C. Duran-Osuna, I. Heredia-De La
Cruz34, R. Lopez-Fernandez, J. Mejia Guisao, R.I. Rabadan-Trejo, M. Ramirez-
Garcia, G. Ramirez-Sanchez, R. Reyes-Almanza, A. Sanchez-Hernandez Universidad
Iberoamericana, Mexico City, Mexico
S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia Benemerita
Universidad Autonoma de Puebla, Puebla, Mexico
J. Eysermans, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada Universidad
Autónoma de San Luis Potosí, San Luis Potosí, Mexico
A. Morelos Pineda University of Auckland, Auckland, New Zealand
D. Krofcheck University of Canterbury, Christchurch, New Zealand
S. Bheesette, P.H. Butler National Centre for Physics, Quaid-I-Azam
University, Islamabad, Pakistan
A. Ahmad, M. Ahmad, M.I. Asghar, Q. Hassan, H.R. Hoorani, A. Saddique, M.A.
Shah, M. Shoaib, M. Waqas National Centre for Nuclear Research, Swierk, Poland
H. Bialkowska, M. Bluj, B. Boimska, T. Frueboes, M. Górski, M. Kazana, M.
Szleper, P. Traczyk, P. Zalewski Institute of Experimental Physics, Faculty of
Physics, University of Warsaw, Warsaw, Poland
K. Bunkowski, A. Byszuk35, K. Doroba, A. Kalinowski, M. Konecki, J.
Krolikowski, M. Misiura, M. Olszewski, A. Pyskir, M. Walczak Laboratório de
Instrumentação e Física Experimental de Partículas, Lisboa, Portugal
M. Araujo, P. Bargassa, C. Beirão Da Cruz E Silva, A. Di Francesco, P.
Faccioli, B. Galinhas, M. Gallinaro, J. Hollar, N. Leonardo, J. Seixas, G.
Strong, O. Toldaiev, J. Varela Joint Institute for Nuclear Research, Dubna,
Russia
S. Afanasiev, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev,
V. Karjavine, A. Lanev, A. Malakhov, V. Matveev36,37, P. Moisenz, V. Palichik,
V. Perelygin, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N. Voytishin,
A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg),
Russia
V. Golovtsov, Y. Ivanov, V. Kim38, E. Kuznetsova39, P. Levchenko, V. Murzin,
V. Oreshkin, I. Smirnov, D. Sosnov, V. Sulimov, L. Uvarov, S. Vavilov, A.
Vorobyev Institute for Nuclear Research, Moscow, Russia
Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov,
N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin Institute for Theoretical
and Experimental Physics, Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Lychkovskaya, V. Popov, I. Pozdnyakov, G.
Safronov, A. Spiridonov, A. Stepennov, V. Stolin, M. Toms, E. Vlasov, A.
Zhokin Moscow Institute of Physics and Technology, Moscow, Russia
T. Aushev National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
R. Chistov40, M. Danilov40, P. Parygin, D. Philippov, S. Polikarpov40, E.
Tarkovskii P.N. Lebedev Physical Institute, Moscow, Russia
V. Andreev, M. Azarkin, I. Dremin37, M. Kirakosyan, A. Terkulov Skobeltsyn
Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow,
Russia
A. Baskakov, A. Belyaev, E. Boos, V. Bunichev, M. Dubinin41, L. Dudko, A.
Ershov, V. Klyukhin, N. Korneeva, I. Lokhtin, I. Miagkov, S. Obraztsov, M.
Perfilov, V. Savrin, P. Volkov Novosibirsk State University (NSU),
Novosibirsk, Russia
A. Barnyakov42, V. Blinov42, T. Dimova42, L. Kardapoltsev42, Y. Skovpen42
Institute for High Energy Physics of National Research Centre ’Kurchatov
Institute’, Protvino, Russia
I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, A. Kalinin, D.
Konstantinov, P. Mandrik, V. Petrov, R. Ryutin, S. Slabospitskii, A. Sobol, S.
Troshin, N. Tyurin, A. Uzunian, A. Volkov National Research Tomsk Polytechnic
University, Tomsk, Russia
A. Babaev, S. Baidali, V. Okhotnikov University of Belgrade, Faculty of
Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia
P. Adzic43, P. Cirkovic, D. Devetak, M. Dordevic, J. Milosevic Centro de
Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid,
Spain
J. Alcaraz Maestre, A. Álvarez Fernández, I. Bachiller, M. Barrio Luna, J.A.
Brochero Cifuentes, M. Cerrada, N. Colino, B. De La Cruz, A. Delgado Peris, C.
Fernandez Bedoya, J.P. Fernández Ramos, J. Flix, M.C. Fouz, O. Gonzalez Lopez,
S. Goy Lopez, J.M. Hernandez, M.I. Josa, D. Moran, A. Pérez-Calero Yzquierdo,
J. Puerta Pelayo, I. Redondo, L. Romero, S. Sánchez Navas, M.S. Soares, A.
Triossi Universidad Autónoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Trocóniz Universidad de Oviedo, Oviedo, Spain
J. Cuevas, C. Erice, J. Fernandez Menendez, S. Folgueras, I. Gonzalez
Caballero, J.R. González Fernández, E. Palencia Cortezon, V. Rodríguez Bouza,
S. Sanchez Cruz, J.M. Vizan Garcia Instituto de Física de Cantabria (IFCA),
CSIC-Universidad de Cantabria, Santander, Spain
I.J. Cabrillo, A. Calderon, B. Chazin Quero, J. Duarte Campderros, M.
Fernandez, P.J. Fernández Manteca, A. García Alonso, J. Garcia-Ferrero, G.
Gomez, A. Lopez Virto, J. Marco, C. Martinez Rivero, P. Martinez Ruiz del
Arbol, F. Matorras, J. Piedra Gomez, C. Prieels, T. Rodrigo, A. Ruiz-Jimeno,
L. Scodellaro, N. Trevisani, I. Vila, R. Vilar Cortabitarte University of
Ruhuna, Department of Physics, Matara, Sri Lanka
N. Wickramage CERN, European Organization for Nuclear Research, Geneva,
Switzerland
D. Abbaneo, B. Akgun, E. Auffray, G. Auzinger, P. Baillon, A.H. Ball, D.
Barney, J. Bendavid, M. Bianco, A. Bocci, C. Botta, E. Brondolin, T.
Camporesi, M. Cepeda, G. Cerminara, E. Chapon, Y. Chen, G. Cucciati, D.
d’Enterria, A. Dabrowski, N. Daci, V. Daponte, A. David, A. De Roeck, N.
Deelen, M. Dobson, M. Dünser, N. Dupont, A. Elliott-Peisert, P. Everaerts, F.
Fallavollita44, D. Fasanella, G. Franzoni, J. Fulcher, W. Funk, D. Gigi, A.
Gilbert, K. Gill, F. Glege, M. Gruchala, M. Guilbaud, D. Gulhan, J. Hegeman,
C. Heidegger, V. Innocente, A. Jafari, P. Janot, O. Karacheban19, J. Kieseler,
A. Kornmayer, M. Krammer1, C. Lange, P. Lecoq, C. Lourenço, L. Malgeri, M.
Mannelli, A. Massironi, F. Meijers, J.A. Merlin, S. Mersi, E. Meschi, P.
Milenovic45, F. Moortgat, M. Mulders, J. Ngadiuba, S. Nourbakhsh, S.
Orfanelli, L. Orsini, F. Pantaleo16, L. Pape, E. Perez, M. Peruzzi, A.
Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, F.M. Pitters, D. Rabady, A.
Racz, T. Reis, M. Rovere, H. Sakulin, C. Schäfer, C. Schwick, M. Selvaggi, A.
Sharma, P. Silva, P. Sphicas46, A. Stakia, J. Steggemann, D. Treille, A.
Tsirou, V. Veckalns47, M. Verzetti, W.D. Zeuner Paul Scherrer Institut,
Villigen, Switzerland
L. Caminada48, K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C.
Kaestli, D. Kotlinski, U. Langenegger, T. Rohe, S.A. Wiederkehr ETH Zurich -
Institute for Particle Physics and Astrophysics (IPA), Zurich, Switzerland
M. Backhaus, L. Bäni, P. Berger, N. Chernyavskaya, G. Dissertori, M. Dittmar,
M. Donegà, C. Dorfer, T.A. Gómez Espinosa, C. Grab, D. Hits, T. Klijnsma, W.
Lustermann, R.A. Manzoni, M. Marionneau, M.T. Meinhard, F. Micheli, P.
Musella, F. Nessi-Tedaldi, J. Pata, F. Pauss, G. Perrin, L. Perrozzi, S.
Pigazzini, M. Quittnat, C. Reissel, D. Ruini, D.A. Sanz Becerra, M.
Schönenberger, L. Shchutska, V.R. Tavolaro, K. Theofilatos, M.L. Vesterbacka
Olsson, R. Wallny, D.H. Zhu Universität Zürich, Zurich, Switzerland
T.K. Aarrestad, C. Amsler49, D. Brzhechko, M.F. Canelli, A. De Cosa, R. Del
Burgo, S. Donato, C. Galloni, T. Hreus, B. Kilminster, S. Leontsinis, I.
Neutelings, G. Rauco, P. Robmann, D. Salerno, K. Schweiger, C. Seitz, Y.
Takahashi, A. Zucchetta National Central University, Chung-Li, Taiwan
T.H. Doan, R. Khurana, C.M. Kuo, W. Lin, A. Pozdnyakov, S.S. Yu National
Taiwan University (NTU), Taipei, Taiwan
P. Chang, Y. Chao, K.F. Chen, P.H. Chen, W.-S. Hou, Y.F. Liu, R.-S. Lu, E.
Paganis, A. Psallidas, A. Steen Chulalongkorn University, Faculty of Science,
Department of Physics, Bangkok, Thailand
B. Asavapibhop, N. Srimanobhas, N. Suwonjandee Çukurova University, Physics
Department, Science and Art Faculty, Adana, Turkey
A. Bat, F. Boran, S. Cerci50, S. Damarseckin, Z.S. Demiroglu, F. Dolek, C.
Dozen, I. Dumanoglu, S. Girgis, G. Gokbulut, Y. Guler, E. Gurpinar, I. Hos51,
C. Isik, E.E. Kangal52, O. Kara, A. Kayis Topaksu, U. Kiminsu, M. Oglakci, G.
Onengut, K. Ozdemir53, S. Ozturk54, D. Sunar Cerci50, B. Tali50, U.G. Tok, S.
Turkcapar, I.S. Zorbakir, C. Zorbilmez Middle East Technical University,
Physics Department, Ankara, Turkey
B. Isildak55, G. Karapinar56, M. Yalvac, M. Zeyrek Bogazici University,
Istanbul, Turkey
I.O. Atakisi, E. Gülmez, M. Kaya57, O. Kaya58, S. Ozkorucuklu59, S. Tekten,
E.A. Yetkin60 Istanbul Technical University, Istanbul, Turkey
M.N. Agaras, A. Cakir, K. Cankocak, Y. Komurcu, S. Sen61 Institute for
Scintillation Materials of National Academy of Science of Ukraine, Kharkov,
Ukraine
B. Grynyov National Scientific Center, Kharkov Institute of Physics and
Technology, Kharkov, Ukraine
L. Levchuk University of Bristol, Bristol, United Kingdom
F. Ball, J.J. Brooke, D. Burns, E. Clement, D. Cussans, O. Davignon, H.
Flacher, J. Goldstein, G.P. Heath, H.F. Heath, L. Kreczko, D.M. Newbold62, S.
Paramesvaran, B. Penning, T. Sakuma, D. Smith, V.J. Smith, J. Taylor, A.
Titterton Rutherford Appleton Laboratory, Didcot, United Kingdom
K.W. Bell, A. Belyaev63, C. Brew, R.M. Brown, D. Cieri, D.J.A. Cockerill, J.A.
Coughlan, K. Harder, S. Harper, J. Linacre, K. Manolopoulos, E. Olaiya, D.
Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin, T. Williams, W.J.
Womersley Imperial College, London, United Kingdom
R. Bainbridge, P. Bloch, J. Borg, S. Breeze, O. Buchmuller, A. Bundock, D.
Colling, P. Dauncey, G. Davies, M. Della Negra, R. Di Maria, G. Hall, G. Iles,
T. James, M. Komm, C. Laner, L. Lyons, A.-M. Magnan, S. Malik, A. Martelli, J.
Nash64, A. Nikitenko7, V. Palladino, M. Pesaresi, D.M. Raymond, A. Richards,
A. Rose, E. Scott, C. Seez, A. Shtipliyski, G. Singh, M. Stoye, T. Strebler,
S. Summers, A. Tapper, K. Uchida, T. Virdee16, N. Wardle, D. Winterbottom, J.
Wright, S.C. Zenz Brunel University, Uxbridge, United Kingdom
J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, C.K. Mackay, A. Morton, I.D. Reid,
L. Teodorescu, S. Zahid Baylor University, Waco, USA
K. Call, J. Dittmann, K. Hatakeyama, H. Liu, C. Madrid, B. McMaster, N.
Pastika, C. Smith Catholic University of America, Washington, DC, USA
R. Bartek, A. Dominguez The University of Alabama, Tuscaloosa, USA
A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio, C. West Boston University,
Boston, USA
D. Arcaro, T. Bose, D. Gastler, D. Pinna, D. Rankin, C. Richardson, J. Rohlf,
L. Sulak, D. Zou Brown University, Providence, USA
G. Benelli, X. Coubez, D. Cutts, M. Hadley, J. Hakala, U. Heintz, J.M.
Hogan65, K.H.M. Kwok, E. Laird, G. Landsberg, J. Lee, Z. Mao, M. Narain, S.
Sagir66, R. Syarif, E. Usai, D. Yu University of California, Davis, Davis, USA
R. Band, C. Brainerd, R. Breedon, D. Burns, M. Calderon De La Barca Sanchez,
M. Chertok, J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk,
W. Ko, O. Kukral, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, S. Shalhout,
M. Shi, D. Stolp, D. Taylor, K. Tos, M. Tripathi, Z. Wang, F. Zhang University
of California, Los Angeles, USA
M. Bachtis, C. Bravo, R. Cousins, A. Dasgupta, A. Florent, J. Hauser, M.
Ignatenko, N. Mccoll, S. Regnard, D. Saltzberg, C. Schnaible, V. Valuev
University of California, Riverside, Riverside, USA
E. Bouvier, K. Burt, R. Clare, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, G.
Karapostoli, E. Kennedy, F. Lacroix, O.R. Long, M. Olmedo Negrete, M.I.
Paneva, W. Si, L. Wang, H. Wei, S. Wimpenny, B.R. Yates University of
California, San Diego, La Jolla, USA
J.G. Branson, P. Chang, S. Cittolin, M. Derdzinski, R. Gerosa, D. Gilbert, B.
Hashemi, A. Holzner, D. Klein, G. Kole, V. Krutelyov, J. Letts, M.
Masciovecchio, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon,
M. Tadel, A. Vartak, S. Wasserbaech67, J. Wood, F. Würthwein, A. Yagil, G.
Zevi Della Porta University of California, Santa Barbara - Department of
Physics, Santa Barbara, USA
N. Amin, R. Bhandari, C. Campagnari, M. Citron, V. Dutta, M. Franco Sevilla,
L. Gouskos, R. Heller, J. Incandela, H. Mei, A. Ovcharova, H. Qu, J. Richman,
D. Stuart, I. Suarez, S. Wang, J. Yoo California Institute of Technology,
Pasadena, USA
D. Anderson, A. Bornheim, J.M. Lawhorn, N. Lu, H.B. Newman, T.Q. Nguyen, M.
Spiropulu, J.R. Vlimant, R. Wilkinson, S. Xie, Z. Zhang, R.Y. Zhu Carnegie
Mellon University, Pittsburgh, USA
M.B. Andrews, T. Ferguson, T. Mudholkar, M. Paulini, M. Sun, I. Vorobiev, M.
Weinberg University of Colorado Boulder, Boulder, USA
J.P. Cumalat, W.T. Ford, F. Jensen, A. Johnson, E. MacDonald, T. Mulholland,
R. Patel, A. Perloff, K. Stenson, K.A. Ulmer, S.R. Wagner Cornell University,
Ithaca, USA
J. Alexander, J. Chaves, Y. Cheng, J. Chu, A. Datta, K. Mcdermott, N. Mirman,
J.R. Patterson, D. Quach, A. Rinkevicius, A. Ryd, L. Skinnari, L. Soffi, S.M.
Tan, Z. Tao, J. Thom, J. Tucker, P. Wittich, M. Zientek Fermi National
Accelerator Laboratory, Batavia, USA
S. Abdullin, M. Albrow, M. Alyari, G. Apollinari, A. Apresyan, A. Apyan, S.
Banerjee, L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, K. Burkett,
J.N. Butler, A. Canepa, G.B. Cerati, H.W.K. Cheung, F. Chlebana, M. Cremonesi,
J. Duarte, V.D. Elvira, J. Freeman, Z. Gecse, E. Gottschalk, L. Gray, D.
Green, S. Grünendahl, O. Gutsche, J. Hanlon, R.M. Harris, S. Hasegawa, J.
Hirschauer, Z. Hu, B. Jayatilaka, S. Jindariani, M. Johnson, U. Joshi, B.
Klima, M.J. Kortelainen, B. Kreis, S. Lammel, D. Lincoln, R. Lipton, M. Liu,
T. Liu, J. Lykken, K. Maeshima, J.M. Marraffino, D. Mason, P. McBride, P.
Merkel, S. Mrenna, S. Nahn, V. O’Dell, K. Pedro, C. Pena, O. Prokofyev, G.
Rakness, L. Ristori, A. Savoy-Navarro68, B. Schneider, E. Sexton-Kennedy, A.
Soha, W.J. Spalding, L. Spiegel, S. Stoynev, J. Strait, N. Strobbe, L. Taylor,
S. Tkaczyk, N.V. Tran, L. Uplegger, E.W. Vaandering, C. Vernieri, M.
Verzocchi, R. Vidal, M. Wang, H.A. Weber, A. Whitbeck University of Florida,
Gainesville, USA
D. Acosta, P. Avery, P. Bortignon, D. Bourilkov, A. Brinkerhoff, L. Cadamuro,
A. Carnes, D. Curry, R.D. Field, S.V. Gleyzer, B.M. Joshi, J. Konigsberg, A.
Korytov, K.H. Lo, P. Ma, K. Matchev, G. Mitselmakher, D. Rosenzweig, K. Shi,
D. Sperka, J. Wang, S. Wang, X. Zuo Florida International University, Miami,
USA
Y.R. Joshi, S. Linn Florida State University, Tallahassee, USA
A. Ackert, T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, T.
Kolberg, G. Martinez, T. Perry, H. Prosper, A. Saha, C. Schiber, R. Yohay
Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, V. Bhopatkar, S. Colafranceschi, M. Hohlmann, D. Noonan, M.
Rahmani, T. Roy, F. Yumiceva University of Illinois at Chicago (UIC), Chicago,
USA
M.R. Adams, L. Apanasevich, D. Berry, R.R. Betts, R. Cavanaugh, X. Chen, S.
Dittmer, O. Evdokimov, C.E. Gerber, D.A. Hangal, D.J. Hofman, K. Jung, J.
Kamin, C. Mills, M.B. Tonjes, N. Varelas, H. Wang, X. Wang, Z. Wu, J. Zhang
The University of Iowa, Iowa City, USA
M. Alhusseini, B. Bilki69, W. Clarida, K. Dilsiz70, S. Durgut, R.P.
Gandrajula, M. Haytmyradov, V. Khristenko, J.-P. Merlo, A. Mestvirishvili, A.
Moeller, J. Nachtman, H. Ogul71, Y. Onel, F. Ozok72, A. Penzo, C. Snyder, E.
Tiras, J. Wetzel Johns Hopkins University, Baltimore, USA
B. Blumenfeld, A. Cocoros, N. Eminizer, D. Fehling, L. Feng, A.V. Gritsan,
W.T. Hung, P. Maksimovic, J. Roskes, U. Sarica, M. Swartz, M. Xiao, C. You The
University of Kansas, Lawrence, USA
A. Al-bataineh, P. Baringer, A. Bean, S. Boren, J. Bowen, A. Bylinkin, J.
Castle, S. Khalil, A. Kropivnitskaya, D. Majumder, W. Mcbrayer, M. Murray, C.
Rogan, S. Sanders, E. Schmitz, J.D. Tapia Takaki, Q. Wang Kansas State
University, Manhattan, USA
S. Duric, A. Ivanov, K. Kaadze, D. Kim, Y. Maravin, D.R. Mendis, T. Mitchell,
A. Modak, A. Mohammadi Lawrence Livermore National Laboratory, Livermore, USA
F. Rebassoo, D. Wright University of Maryland, College Park, USA
A. Baden, O. Baron, A. Belloni, S.C. Eno, Y. Feng, C. Ferraioli, N.J. Hadley,
S. Jabeen, G.Y. Jeng, R.G. Kellogg, J. Kunkle, A.C. Mignerey, S. Nabili, F.
Ricci-Tam, M. Seidel, Y.H. Shin, A. Skuja, S.C. Tonwar, K. Wong Massachusetts
Institute of Technology, Cambridge, USA
D. Abercrombie, B. Allen, V. Azzolini, A. Baty, G. Bauer, R. Bi, S. Brandt, W.
Busza, I.A. Cali, M. D’Alfonso, Z. Demiragli, G. Gomez Ceballos, M. Goncharov,
P. Harris, D. Hsu, M. Hu, Y. Iiyama, G.M. Innocenti, M. Klute, D. Kovalskyi,
Y.-J. Lee, P.D. Luckey, B. Maier, A.C. Marini, C. Mcginn, C. Mironov, S.
Narayanan, X. Niu, C. Paus, C. Roland, G. Roland, Z. Shi, G.S.F. Stephans, K.
Sumorok, K. Tatar, D. Velicanu, J. Wang, T.W. Wang, B. Wyslouch University of
Minnesota, Minneapolis, USA
A.C. Benvenuti${}^{\textrm{\textdagger}}$, R.M. Chatterjee, A. Evans, P.
Hansen, J. Hiltbrand, Sh. Jain, S. Kalafut, M. Krohn, Y. Kubota, Z. Lesko, J.
Mans, N. Ruckstuhl, R. Rusack, M.A. Wadud University of Mississippi, Oxford,
USA
J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, USA
E. Avdeeva, K. Bloom, D.R. Claes, C. Fangmeier, F. Golf, R. Gonzalez Suarez,
R. Kamalieddin, I. Kravchenko, J. Monroy, J.E. Siado, G.R. Snow, B. Stieger
State University of New York at Buffalo, Buffalo, USA
A. Godshalk, C. Harrington, I. Iashvili, A. Kharchilava, C. Mclean, D. Nguyen,
A. Parker, S. Rappoccio, B. Roozbahani Northeastern University, Boston, USA
G. Alverson, E. Barberis, C. Freer, Y. Haddad, A. Hortiangtham, D.M. Morse, T.
Orimoto, T. Wamorkar, B. Wang, A. Wisecarver, D. Wood Northwestern University,
Evanston, USA
S. Bhattacharya, J. Bueghly, O. Charaf, T. Gunter, K.A. Hahn, N. Odell, M.H.
Schmitt, K. Sung, M. Trovato, M. Velasco University of Notre Dame, Notre Dame,
USA
R. Bucci, N. Dev, M. Hildreth, K. Hurtado Anampa, C. Jessop, D.J. Karmgard, K.
Lannon, W. Li, N. Loukas, N. Marinelli, F. Meng, C. Mueller, Y. Musienko36, M.
Planer, A. Reinsvold, R. Ruchti, P. Siddireddy, G. Smith, S. Taroni, M. Wayne,
A. Wightman, M. Wolf, A. Woodard The Ohio State University, Columbus, USA
J. Alimena, L. Antonelli, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, C.
Hill, W. Ji, T.Y. Ling, W. Luo, B.L. Winer Princeton University, Princeton,
USA
S. Cooperstein, P. Elmer, J. Hardenbrook, N. Haubrich, S. Higginbotham, A.
Kalogeropoulos, S. Kwan, D. Lange, M.T. Lucchini, J. Luo, D. Marlow, K. Mei,
I. Ojalvo, J. Olsen, C. Palmer, P. Piroué, J. Salfeld-Nebgen, D. Stickland, C.
Tully University of Puerto Rico, Mayaguez, USA
S. Malik, S. Norberg Purdue University, West Lafayette, USA
A. Barker, V.E. Barnes, S. Das, L. Gutay, M. Jones, A.W. Jung, A. Khatiwada,
B. Mahakud, D.H. Miller, N. Neumeister, C.C. Peng, S. Piperov, H. Qiu, J.F.
Schulte, J. Sun, F. Wang, R. Xiao, W. Xie Purdue University Northwest,
Hammond, USA
T. Cheng, J. Dolen, N. Parashar Rice University, Houston, USA
Z. Chen, K.M. Ecklund, S. Freed, F.J.M. Geurts, M. Kilpatrick, Arun Kumar, W.
Li, B.P. Padley, R. Redjimi, J. Roberts, J. Rorie, W. Shi, Z. Tu, A. Zhang
University of Rochester, Rochester, USA
A. Bodek, P. de Barbaro, R. Demina, Y.t. Duh, J.L. Dulemba, C. Fallon, T.
Ferbel, M. Galanti, A. Garcia-Bellido, J. Han, O. Hindrichs, A.
Khukhunaishvili, E. Ranken, P. Tan, R. Taus Rutgers, The State University of
New Jersey, Piscataway, USA
J.P. Chou, Y. Gershtein, E. Halkiadakis, A. Hart, M. Heindl, E. Hughes, S.
Kaplan, R. Kunnawalkam Elayavalli, S. Kyriacou, I. Laflotte, A. Lath, R.
Montalvo, K. Nash, M. Osherson, H. Saka, S. Salur, S. Schnetzer, D. Sheffield,
S. Somalwar, R. Stone, S. Thomas, P. Thomassen University of Tennessee,
Knoxville, USA
A.G. Delannoy, J. Heideman, G. Riley, S. Spanier Texas A&M University, College
Station, USA
O. Bouhali73, A. Celik, M. Dalchenko, M. De Mattia, A. Delgado, S. Dildick, R.
Eusebi, J. Gilmore, T. Huang, T. Kamon74, S. Luo, D. Marley, R. Mueller, D.
Overton, L. Perniè, D. Rathjens, A. Safonov Texas Tech University, Lubbock,
USA
N. Akchurin, J. Damgov, F. De Guio, P.R. Dudero, S. Kunori, K. Lamichhane,
S.W. Lee, T. Mengke, S. Muthumuni, T. Peltola, S. Undleeb, I. Volobouev, Z.
Wang Vanderbilt University, Nashville, USA
S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K.
Padeken, F. Romeo, J.D. Ruiz Alvarez, P. Sheldon, S. Tuo, J. Velkovska, M.
Verweij, Q. Xu University of Virginia, Charlottesville, USA
M.W. Arenton, P. Barria, B. Cox, R. Hirosky, M. Joyce, A. Ledovskoy, H. Li, C.
Neu, T. Sinthuprasith, Y. Wang, E. Wolfe, F. Xia Wayne State University,
Detroit, USA
R. Harr, P.E. Karchin, N. Poudyal, J. Sturdy, P. Thapa, S. Zaleski University
of Wisconsin - Madison, Madison, WI, USA
J. Buchanan, C. Caillol, D. Carlsmith, S. Dasu, I. De Bruyn, L. Dodd, B.
Gomber, M. Grothe, M. Herndon, A. Hervé, U. Hussain, P. Klabbers, A. Lanaro,
K. Long, R. Loveless, T. Ruggles, A. Savin, V. Sharma, N. Smith, W.H. Smith,
N. Woods †: Deceased
1: Also at Vienna University of Technology, Vienna, Austria
2: Also at IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
3: Also at Universidade Estadual de Campinas, Campinas, Brazil
4: Also at Federal University of Rio Grande do Sul, Porto Alegre, Brazil
5: Also at Université Libre de Bruxelles, Bruxelles, Belgium
6: Also at University of Chinese Academy of Sciences, Beijing, China
7: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia
8: Also at Joint Institute for Nuclear Research, Dubna, Russia
9: Now at British University in Egypt, Cairo, Egypt
10: Now at Cairo University, Cairo, Egypt
11: Now at Ain Shams University, Cairo, Egypt
12: Also at Department of Physics, King Abdulaziz University, Jeddah, Saudi
Arabia
13: Also at Université de Haute Alsace, Mulhouse, France
14: Also at Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State
University, Moscow, Russia
15: Also at Ilia State University, Tbilisi, Georgia
16: Also at CERN, European Organization for Nuclear Research, Geneva,
Switzerland
17: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen,
Germany
18: Also at University of Hamburg, Hamburg, Germany
19: Also at Brandenburg University of Technology, Cottbus, Germany
20: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary
21: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary
22: Also at MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
23: Also at Indian Institute of Technology Bhubaneswar, Bhubaneswar, India
24: Also at Institute of Physics, Bhubaneswar, India
25: Also at Shoolini University, Solan, India
26: Also at University of Visva-Bharati, Santiniketan, India
27: Also at Isfahan University of Technology, Isfahan, Iran
28: Also at Plasma Physics Research Center, Science and Research Branch,
Islamic Azad University, Tehran, Iran
29: Also at Università degli Studi di Siena, Siena, Italy
30: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy
31: Also at Kyunghee University, Seoul, Korea
32: Also at International Islamic University of Malaysia, Kuala Lumpur,
Malaysia
33: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia
34: Also at Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
35: Also at Warsaw University of Technology, Institute of Electronic Systems,
Warsaw, Poland
36: Also at Institute for Nuclear Research, Moscow, Russia
37: Now at National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
38: Also at St. Petersburg State Polytechnical University, St. Petersburg,
Russia
39: Also at University of Florida, Gainesville, USA
40: Also at P.N. Lebedev Physical Institute, Moscow, Russia
41: Also at California Institute of Technology, Pasadena, USA
42: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia
43: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia
44: Also at INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy
45: Also at University of Belgrade, Faculty of Physics and Vinca Institute of
Nuclear Sciences, Belgrade, Serbia
46: Also at National and Kapodistrian University of Athens, Athens, Greece
47: Also at Riga Technical University, Riga, Latvia
48: Also at Universität Zürich, Zurich, Switzerland
49: Also at Stefan Meyer Institute for Subatomic Physics (SMI), Vienna,
Austria
50: Also at Adiyaman University, Adiyaman, Turkey
51: Also at Istanbul Aydin University, Istanbul, Turkey
52: Also at Mersin University, Mersin, Turkey
53: Also at Piri Reis University, Istanbul, Turkey
54: Also at Gaziosmanpasa University, Tokat, Turkey
55: Also at Ozyegin University, Istanbul, Turkey
56: Also at Izmir Institute of Technology, Izmir, Turkey
57: Also at Marmara University, Istanbul, Turkey
58: Also at Kafkas University, Kars, Turkey
59: Also at Istanbul University, Faculty of Science, Istanbul, Turkey
60: Also at Istanbul Bilgi University, Istanbul, Turkey
61: Also at Hacettepe University, Ankara, Turkey
62: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom
63: Also at School of Physics and Astronomy, University of Southampton,
Southampton, United Kingdom
64: Also at Monash University, Faculty of Science, Clayton, Australia
65: Also at Bethel University, St. Paul, USA
66: Also at Karamanoğlu Mehmetbey University, Karaman, Turkey
67: Also at Utah Valley University, Orem, USA
68: Also at Purdue University, West Lafayette, USA
69: Also at Beykent University, Istanbul, Turkey
70: Also at Bingol University, Bingol, Turkey
71: Also at Sinop University, Sinop, Turkey
72: Also at Mimar Sinan University, Istanbul, Istanbul, Turkey
73: Also at Texas A&M University at Qatar, Doha, Qatar
74: Also at Kyungpook National University, Daegu, Korea