FSQ-16-006

FSQ-16-006

# Study of central exclusive $\PGpp\PGpm$ production in proton-proton
collisions at $\sqrt{s}=5.02$ and 13

###### Abstract

Central exclusive and semiexclusive production of $\PGpp\PGpm$ pairs is
measured with the CMS detector in proton-proton collisions at the LHC at
center-of-mass energies of 5.02 and 13. The theoretical description of these
nonperturbative processes, which have not yet been measured in detail at the
LHC, poses a significant challenge to models. The two pions are measured and
identified in the CMS silicon tracker based on specific energy loss, whereas
the absence of other particles is ensured by calorimeter information. The
total and differential cross sections of exclusive and semiexclusive central
$\PGpp\PGpm$ production are measured as functions of invariant mass,
transverse momentum, and rapidity of the $\PGpp\PGpm$ system in the fiducial
region defined as transverse momentum $\pt(\PGp)>0.2\GeV$ and pseudorapidity
$\abs{\eta(\PGp)}<2.4$. The production cross sections for the four resonant
channels 500, $\PGrzP{770}$, 980, and 1270 are extracted using a simple model.
These results represent the first measurement of this process at the LHC
collision energies of 5.02 and 13.

##  0.1 Introduction

The central exclusive production (CEP) process has been studied for a long
time from both theoretical [1, 2, 3, 4, 5, 6, 7] and experimental [8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18] perspectives. In this process, both protons
remain intact in the collision and a central system is produced. The process
is referred to as exclusive when no particles other than the central system
are produced. If one or both protons dissociate into a forward diffractive
system, the process is called semiexclusive production. Various central
systems can be produced in this process, like $\PGpp\PGpm$, $\PKp\PKm$, and
$4\PGp$. In this paper, the $\PGpp\PGpm$ central system is measured. At the
CERN LHC energies, the two dominant mechanisms of $\PGpp\PGpm$ production via
CEP are _double pomeron exchange_ (DPE) and _vector meson photoproduction_
(VMP), which are illustrated by the diagrams shown in Fig. 1. The pomeron
($\mathbb{P}$) is a color singlet object introduced to explain the rise of the
inelastic cross section at high collision energies [19, 20]. The quantum
numbers of the pomeron constrain the possible central systems in DPE
processes, whereas the photon exchange restricts the central system in VMP
processes. By functioning as a quantum number filter, the CEP process is
suitable to study low-mass resonances, which would be difficult to study
otherwise. Furthermore, DPE processes are also suitable to search for
glueballs (bound states of gluons without valence quarks), because they
provide a gluon-rich environment [21, 22]. Another process that could
contribute to the same final state is the two-photon fusion
$\PGg\PGg\to\PGpp\PGpm$, which is expected to have a much smaller cross
section than DPE and VMP processes and gives a negligible contribution [23].

Figure 1: Diagrams of the dominant mechanisms for $\PGpp\PGpm$ production via
CEP in proton-proton collisions: (a) continuum; (b) resonant double pomeron
exchange; and (c) vector meson photoproduction.

The DPE process of pion pair production has two subcategories: continuum and
resonant production. In the case of continuum production, the pion pair is
directly produced; thus the pairs have a nonresonant invariant mass spectrum.
Resonant production means that an intermediate meson resonance is produced
centrally, which manifests itself as a peak in the invariant mass distribution
of the pion pair. Since the pomeron is a Regge trajectory running over states
with quantum numbers $J^{PC}=\\{0^{++},1^{++},2^{++},\dots\\}$ and
$I^{G}=0^{+}$, the resonance is restricted to have $J^{PC}=\\{0^{++}$,
$2^{++}$, $4^{++},\dots\\}$ and $I^{G}=0^{+}$, where $J$ is the total angular
momentum, $I$ is the isospin, $P$ is the parity, $C$ is the charge parity, and
$G=C\,(-1)^{I}$. The known particles [24] satisfying these criteria are the
f0, f2, ${\HepParticle{\PGc}{c0}{}}\Xspace$,
${\HepParticle{\PGc}{c2}{}}\Xspace$, ${\HepParticle{\PGc}{b0}{}}\Xspace$, and
${\HepParticle{\PGc}{b2}{}}\Xspace$ resonances. The cross section for DPE
($\sigma_{\PGpp\PGpm}^{\text{DPE}}$) can be calculated from the amplitude of
continuum ($A_{\PGpp\PGpm}^{\text{DPE,C}}$) and resonant
($A_{\PGpp\PGpm}^{\text{DPE,R}}$) production as

$\sigma_{\PGpp\PGpm}^{\text{DPE}}\propto\abs{A_{\PGpp\PGpm}^{\text{DPE,C}}+A_{\PGpp\PGpm}^{\text{DPE,R}}}^{2}.$
(1)

Interference terms between the continuum and resonant production channels must
be included to describe the observed spectra and to measure the cross sections
for resonances.

In VMP, one of the protons emits a virtual photon, which fluctuates into a
quark-antiquark bound state and scatters from the proton via the pomeron
exchange. The quantum numbers of the possible resonances are constrained by
the quantum numbers of the pomeron and the photon ($J^{PC}=1^{--}$), leading
to mesons with odd spin and the following quantum numbers
$J^{PC}=\\{1^{--},3^{--},\dots\\}$. Resonances satisfying these conditions are
${\HepParticle{\PGr}{}{0}{}{}{}}$, $\PGo$, $\PGf$, , $\PGyP{2S}$, and $\PGU$,
but only the ${\HepParticle{\PGr}{}{0}{}{}{}}\to\PGpp\PGpm$ decay has a
significant branching fraction, since decays in this channel are strongly
suppressed in the case of $\PGf$, , $\PGyP{2S}$, and $\PGU$ according to the
Okubo–Zweig–Iizuka rule [25, 26, 27] and in the case of $\PGo$ because of
G-parity conservation [28].

This paper presents measurements of exclusive and semiexclusive $\PGpp\PGpm$
total and differential cross sections as functions of invariant mass
$m(\PGpp\PGpm)$, transverse momentum $\pt(\PGpp\PGpm)$, and rapidity
$y(\PGpp\PGpm)$ of the pion pair, in a fiducial region defined by single pion
transverse momentum $\pt(\PGp)>0.2\GeV$ and single pion pseudorapidity
$\abs{\eta(\PGp)}<2.4$. Because the outgoing protons are not tagged in this
measurement, there is a residual contribution from semiexclusive production
with all dissociation products outside the $\abs{\eta}>4.9$ range. In the
following, the exclusive and the residual semiexclusive contribution together
will be referred to as central exclusive production. The data were recorded by
CMS with beam conditions ensuring a small probability of multiple $\Pp\Pp$
collisions in the same bunch crossing (pileup) in August 2015 at a center-of-
mass energy of 13with luminosity 258and in November 2015 at 5.02with a
luminosity of 522. The average number of $\Pp\Pp$ collisions in a bunch
crossing was around 0.3–0.5 for the 5.02and around 0.5 for the 13data sets.

##  0.2 The CMS detector

The central feature of the CMS apparatus is a superconducting solenoid of 6m
internal diameter. Within the solenoid volume are a 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,
covering the $\abs{\eta}<3.0$ region. Forward calorimeters extend the $\eta$
coverage provided by the barrel and endcap detectors. Muons are measured in
gas-ionization detectors embedded in the steel flux-return yoke outside the
solenoid.

The silicon tracker measures charged particles within the range
$\abs{\eta}<2.5$. It consists of 1440 silicon pixel and 15 148 silicon strip
detector modules and is located in the 3.8T solenoid field. Three pixel barrel
layers (PXB) are situated at radii of 4.4, 7.3, and 10.2cm; PXB also has two
pixel endcap disks (PXF). The strip tracker consists of the innermost tracker
inner barrel (TIB) and the tracker inner disks (TID), which are surrounded by
the tracker outer barrel (TOB). It is completed by endcaps (TEC) on both
sides. The barrel part of the strip tracker has a total of 10 layers at radii
from 25 to 110cm, whereas the endcap of the strip tracker consists of 12
layers. For charged particles with $\pt<1\GeV$ and $\abs{\eta}<1.4$, the track
resolutions are typically 1–2% in , and 90–300 and 100–350for the transverse
and longitudinal impact parameters, respectively [29]. The tracker provides an
opportunity to identify charged particles with $0.3<p<2\GeV$ based on their
specific ionization in the silicon detector elements [30].

The ECAL consists of 75 848 lead tungstate crystals, which provide coverage in
$\abs{\eta}<1.479$ in the barrel region and $1.479<\abs{\eta}<3.0$ in the two
endcap regions.

The barrel and endcap sections of the HCAL consist of 36 wedges each and cover
the $\abs{\eta}<3.0$ region. In the region $\abs{\eta}<1.74$, the HCAL cells
have widths of 0.087 in $\eta$ and 0.087 radians in azimuth ($\phi$). In the
$\eta$-$\phi$ plane, and for $\abs{\eta}<1.48$, the HCAL cells map onto
$5{\times}5$ ECAL crystal arrays to form calorimeter towers projecting
radially outwards from close to the nominal interaction point. At larger
values of $\abs{\eta}$, the towers are larger and the matching ECAL arrays
contain fewer crystals.

The forward hadron (HF) calorimeter uses steel as an absorber and quartz
fibers as the sensitive material. The two halves of the HF are located at
11.2m from the interaction region, one at each end. Together they provide
coverage in the range $3.0<\abs{\eta}<5.2$. Each HF calorimeter consists of
432 readout towers, containing long and short quartz fibers running parallel
to the beam. The long fibers run the entire depth of the HF calorimeter
(165cm, or approximately 10 interaction lengths), whereas the short fibers
start at a depth of 22cm from the front of the detector. By reading out the
two sets of fibers separately, it is possible to distinguish showers generated
by electrons or photons, which deposit a large fraction of their energy in the
long-fiber calorimeter segment, from those generated by hadrons, which
typically produce, on average, nearly equal signals in both calorimeter
segments.

The triggers used in this analysis are based on signals from the Beam Pick-up
and Timing for eXperiments (BPTX) detectors [31]. The BPTX devices have a time
resolution of less than 0.2ns. They are located around the beam pipe at a
distance of $\pm 175$m from the nominal interaction point, and are designed to
provide precise information on the bunch structure and timing of the proton
beams.

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. [32].

##  0.3 Monte Carlo simulations

Two kinds of Monte Carlo (MC) event generators are used in this analysis:
inclusive and exclusive generators. The inclusive generators model the
inclusive diffractive dissociation [33] and nondiffractive interactions, and
are used to estimate the tracking efficiency, multiple reconstruction and
misreconstruction rates. The exclusive generators are used to generate CEP
events and to calculate the vertex correction factors. There are no available
MC event generators that produce exclusive scalar and tensor resonances via
DPE, such as the production of 500, 980, and 1270 mesons.

Event samples are generated with various tunes for diffraction and the
underlying event:

  * •

8.205 [34] with CUETP8M1 tune [35] and MBR model [36]: 8 is an inclusive
generator based on the Schuler and Sjöstrand model. It is capable of modeling
a wide variety of physical processes, such as single diffractive (SD), double
diffractive (DD), and central diffractive (CD) dissociation, as well as
nondiffractive (ND) production [33]. The SD, DD, and ND events are generated
with the CUETP8M1 tune. The Minimum Bias Rockefeller (MBR) model of is based
on the renormalized pomeron flux model and it is capable of generating SD, DD,
ND and CD events.

  * •

epos [37] with its LHC tune [38]: This inclusive generator is based on the
Regge–Gribov phenomenology [39], and it models SD, DD, CD, and ND processes.

  * •

starlight [40]: This event generator models photon-photon and photon-pomeron
interactions in $\Pp\Pp$ and heavy ion collisions. The production of
${\HepParticle{\PGr}{}{0}{}{}{}}$ mesons and their successive decay into two
pions through the VMP process is simulated by starlight. For background
studies, $\PGo$ mesons are also generated with starlight and their decay
simulated by to the $\PGpp\PGpm\PGpz$ final state.

  * •

dime mc 1.06 [5]: The dime mc software describes continuum $\PGpp\PGpm$
production through DPE. The generator uses a phenomenological model based on
Regge theory. Events are generated with the Orear-type off-shell meson form
factors with parameters $a_{\text{or}}=0.71\GeV^{-1}$ and
$b_{\text{or}}=0.91\GeV^{-1}$ [5]. Furthermore, two additional MC samples are
generated with an exponential form factor with $b_{\text{exp}}=0.45$ [5] and
$1\GeV^{-2}$ [1] to study the systematic uncertainty in the measured resonance
cross sections arising from uncertainties in the dime mc parametrization.

All of the generated events are processed by a detailed simulation [41] of the
CMS detector.

##  0.4 Event selection

The following triggers were employed:

  * •

Zero bias: zero-bias events are selected by using either the BPTX detectors
(13data) or the LHC clock signal and the known LHC bunch structure (5.02data).
Both methods provided zero-bias events.

  * •

BPTX XOR: Here XOR stands for the exclusive OR logic, where only one BPTX is
fired, corresponding to an incoming proton bunch from only one direction. This
trigger was used in both 5.02 and 13data sets.

  * •

No-BPTX: There is no signal in the BPTX detectors, which means there are no
incoming proton bunches. This trigger was used in both 5.02 and 13data sets.

The present analysis uses events acquired with the zero bias trigger. The BPTX
XOR and No-BPTX triggers select events with no interacting bunches, which are
used to estimate the electronic noise of calorimeters and possible collisions
between beam particles and residual gas molecules in the CMS beampipe (beam-
gas background). The contribution from beam-gas collisions is negligible
because there is no difference in the measured calorimeter tower energy
distributions for the BPTX XOR and No-BPTX triggered events.

In the offline selections, it is required that the event has exactly two
tracks, both of which satisfy $\chi^{2}/\text{ndf}<2$ (where the $\chi^{2}$
value is calculated based on the fitted trajectory and the measured tracker
hits, and ndf is the number of degrees of freedom), $\pt>0.2\GeV$, and
$\abs{\eta}<2.4$ to ensure high track reconstruction efficiency. Only events
with oppositely charged (opposite-sign, OS) tracks are selected for analysis,
whereas events with same-sign (SS) tracks are used in the background
estimation.

Events with a single collision are selected by requiring the two tracks form a
single reconstructed vertex subject to the constraint that

$\abs{z_{1}-z_{2}}<3\sqrt{\sigma_{1}^{2}+\sigma_{2}^{2}},$ (2)

where $z_{1}$ and $z_{2}$ are the $z$ coordinates of the closest approach of
the reconstructed tracks to the beamline, and $\sigma_{1}$ and $\sigma_{2}$
are their corresponding uncertainties.

To select exclusive events, all calorimeter towers not matching the
trajectories of the two tracks must have energy deposits below a threshold,
which is defined in Table 0.4. A tower is matched to a track if the
intersection of the extrapolated trajectory with the calorimeter surface is
within three standard deviations in $\eta$ and $\phi$ from the center of the
tower. The threshold values are chosen to have a maximum 1% rejection of
signal events resulting from the electronic noise of the calorimeters. Non-
exclusive events might be also selected because of the lack of coverage in the
eta gap between the HF and central calorimeters; these events are also taken
into account in the background estimation presented later in this paper.

Using all of the above listed event selection criteria, a total of 48 961
events were selected from the 5.02and 20 980 from the 13dataset.

The value of calorimeter thresholds for different calorimeter constituents,
used in the selection of exclusive events.  Calorimeter Threshold [] $\eta$
coverage ECAL barrel 0.6 $\abs{\eta}<1.5$ ECAL endcap 3.3 $1.5<\abs{\eta}<3.0$
HCAL barrel 2.0 $\abs{\eta}<1.3$ HCAL endcap 3.8 $1.3<\abs{\eta}<3.0$ HF 4.0
$3.15<\abs{\eta}<5.2$

##  0.5 Data analysis

###  0.5.1 Particle identification

Particle identification is used to select pion pairs by the mean energy loss
($\rd E/\rd x$) of particles in the silicon tracking detectors. The $\rd E/\rd
x$ values shown in the left panel of Fig. 2 are calculated by a second-order
harmonic mean using only the strip detectors [42]:

$\left\langle\frac{\rd E}{\rd
x}\right\rangle=\left(\frac{1}{N}\sum_{i=1}^{N}(\Delta E/\Delta
x)_{i}^{-2}\right)^{-\frac{1}{2}},$ (3)

where $N$ is the number of energy loss measurements, $\Delta E/\Delta x$ is a
single energy loss measurement per path length in one tracker module, and the
sum runs over the strip detectors carrying energy loss measurements. The $-2$
exponent in this formula suppresses high $\Delta E/\Delta x$ values arising
from the highly asymmetric $\Delta E/\Delta x$ Landau distribution, thus
avoiding a bias in the estimate of the average $\rd E/\rd x$ of the track.

Figure 2: Left: The distribution of the logarithm of the mean energy loss and
absolute value of the momentum of tracks from low-multiplicity
($N_{\text{track}}\leq 4$) events collected at $\sqrt{s}=13\TeV$. The
$\PGp$-selection region is shown in the 0.3–2range. All tracks outside this
momentum range are identified as pions. Right: The fit of energy loss
distributions in a given momentum bin with the sum of three Gaussian curves.
Plots are similar for the 5.02data.

The track classification is achieved by fitting the mean energy loss
distributions of tracks from low multiplicity ($N_{\text{track}}\leq 4$)
events with a sum of three Gaussian functions corresponding to pions, kaons,
and protons. An example for such a fit is shown in the right panel of Fig. 2.
In the 0.3–2momentum range pions are selected from the $\pm 3$ standard
deviation region of the corresponding Gaussian peak. This region is shown in
the left panel of Fig. 2. Tracks that have $p<0.3$ or $p>2\GeV$ are assumed to
be pions. The contamination from kaons and protons is estimated using the
data-driven approach described in Section 0.5.3.

###  0.5.2 Corrections

Each event is weighted by several correction factors to compensate for the
detector and reconstruction effects. The multiplying factor is the product of
four independent corrections: tracking, multiple reconstruction, vertex, and
pileup correction.

A tracking correction is used to correct for track reconstruction
inefficiencies:

$C_{\text{tr}}=\frac{1}{\varepsilon_{\text{tr},1}}\,\frac{1}{\varepsilon_{\text{tr},2}},$
(4)

where $\varepsilon_{\text{tr},1}$ ($\varepsilon_{\text{tr},2}$) is the
tracking efficiency in the region where the first (second) particle is
reconstructed. A single charged particle may lead to two reconstructed tracks,
such as spiralling tracks near $\eta\approx 0$ or split tracks in the overlap
region of the tracker barrel and endcap. This effect is corrected using
$\varepsilon_{\text{mrec}}$, which is the probability for this situation to
occur. In this case the correction factor takes the form

$C_{\text{mrec}}=\frac{1}{1-\varepsilon_{\text{mrec},1}}\,\frac{1}{1-\varepsilon_{\text{mrec},2}}.$
(5)

The values of $\varepsilon_{\text{tr}}$ and $\varepsilon_{\text{mrec}}$ are
estimated as a function of $\eta$ and using MC simulations. Their dependence
on the track $\phi$ and the vertex position $z$-coordinate is integrated over.
The simulated events are weighted such that the vertex $z$-coordinate
distribution agrees with collision data.

The vertex correction $C_{\text{vert}}$ accounts for events with an
unreconstructed vertex. It is the reciprocal of the vertex efficiency, which
is calculated using samples produced by the dime mc and starlight generators.
The vertex efficiency has a slight dependence on the invariant mass of the
track pair that is included when applying the vertex correction.

Some real CEP events are rejected because of pileup. To account for these lost
events, a correction factor $C_{\text{pu}}$ for the number of selected events
can be computed. The CEP events are selected from bunch crossings with a
single collision, so by assuming that the number of collisions follows a
Poisson distribution, one can derive $C_{\text{pu}}$:

$C_{\text{pu}}=\frac{N\mu}{N\,\mu\exp{(-\mu)}}=\exp{(\mu)}.$ (6)

Here, $\mu$ is the average number of visible inelastic collisions, in a given
bunch crossing, $N$ is the total number of analyzed events. The value of $\mu$
depends on the instantaneous luminosity associated with individual bunch
crossings, $\mathcal{L}_{\text{bunch}}$, according to the following
expression:

$\mu=\frac{\sigma_{\text{inel,vis}}\mathcal{L}_{\text{bunch}}}{f},$ (7)

where $\sigma_{\text{inel,vis}}$ is the visible inelastic $\Pp\Pp$ cross
section, $f$ is the revolution frequency of protons, and
$\mathcal{L}_{\text{bunch}}$ is the average instantaneous luminosity at the
given bunch crossing position for time periods of 23.3s. The ratio of
$\sigma_{\text{inel,vis}}$ to $f$ is obtained by fitting the fraction of
events with no observed collisions as a function of
$\mathcal{L}_{\text{bunch}}$ with the functional form
$A\exp(-b\,\mathcal{L}_{\text{bunch}})$, where $A$ and $b$ are free parameters
of the fit.

The range of correction factors is summarized in Table 0.5.2.

Correction factors.  Type Range Tracking 1.05–1.50 Multiple reconstruction
1.005–1.040 Vertex 1.05–1.33 Pileup 1.3–2.1

Figure 3: The number of extra calorimeter towers over threshold in events
containing an identified pion pair with opposite (left) and same (right)
charge. The known contributions, denoted with the red hatched areas, are used
to estimate the background in the zero bin of the opposite-sign distribution,
which is denoted by the blue hatched area. The error bars correspond to
statistical uncertainties, whereas the error rectangle on the background
denotes the 14% systematic uncertainty in the background normalization. Plots
are similar for 5.02data.

###  0.5.3 Background estimation

The main background contributions to $\PGpp\PGpm$ CEP are the multiparticle
background and the exclusive $\PKp\PKm$/$\Pp\PAp$ production. The
multiparticle background in the selected exclusive sample consists of events
with more than two particles created in the interaction, of which only two are
observed because the additional particles yield energy deposits below the
thresholds, or outside the acceptance. The SD, DD, ND, and CD processes with
more than two centrally produced particles belong to this contribution. A
method based on control regions is used to estimate this multiparticle
background. Control regions are selected in which events have at least two
calorimeter towers above threshold, not matched to the two selected pions,
with all the other selection criteria satisfied. The distribution of the
number of events selected in this way as a function of the number of extra
towers with energy above threshold is shown in Fig. 3. The counts in the bins
with 2, 3, 4, and 5 towers are used to estimate the background. The
normalization factor is calculated using the following assumption:

$\frac{N_{\text{mpart,SS}}(\text{0 extra towers})}{N_{\text{mpart,SS}}(\text{2
--5 extra towers})}=\frac{N_{\text{mpart,OS}}(\text{0 extra
towers})}{N_{\text{mpart,OS}}(\text{2--5 extra towers})},$ (8)

where $N_{\text{mpart,OS/SS}}$ is the number of multiparticle events with two
OS or SS tracks. The validity of this assumption is checked by comparing the
true and predicted number of background events in inclusive MC samples (Table
0.5.3). The observed discrepancy reflects the differences between OS and SS
events and is included as a systematic uncertainty in the estimate of the
total number of multiparticle background events, as discussed in Section
0.5.4. With this formula and the fact that all SS events are multiparticle
events because of charge conservation, it is possible to calculate the value
of $N_{\text{mpart,OS}}(\text{0 towers})$, which is the number of
multiparticle background events. The expected distribution of the
multiparticle background is obtained using OS events with 2–5 extra
calorimeter towers.

This method does not take into account the background contribution from
$\PGo\to\PGpp\PGpm\PGpz$, because this decay cannot be observed in the SS
events. This latter contribution is negligible (0.5%) based on MC simulation
results.

Checking the validity of Eq. (8) by comparing the true and predicted number of
background events in inclusive MC samples.  Event generator Difference in
normalization epos $(+11\pm 4)\%$ 8 CUETP8M1 $(-5.5\pm 3)\%$ 8 MBR $(+10\pm
4)\%$

Figure 4: Background distributions as functions of kinematic variables
estimated by data-driven methods. The proton dissociation background is not
shown here, since it is included via scaling of the final cross section
values. The error bars correspond to statistical uncertainties. The results
for the 5.02data set are similar.

Genuine exclusive $\PKp\PKm$ and $\Pp\PAp$ events, where both particles are
misidentified as pions, are included in the previous multiparticle background
estimate. To correct for this contribution, the $\PK/\PGp$ ratios are
calculated in the exclusive events using tracks with $p<1\GeV$. Similarly, the
$\Pp/\PGp$ ratio is calculated in the same sample in the range $1<p<2\GeV$.
The $\PK/\PGp$ and $\Pp/\PGp$ ratios are assumed to be $0.3^{+0.1}_{-0.05}$ in
the region $p>1$ and $p>2\GeV$, respectively [43]. Using this assumption and
the measured ratios, the average $\PK/\PGp$ and $\Pp/\PGp$ ratios are then
calculated over the entire momentum range of the exclusive sample. These
average ratios can then be used to compute the number of $\PKp\PKm$ and
$\Pp\PAp$ events under two extreme scenarios. The first scenario assumes that
the production of a $\PK$ or a $\Pp$ is always accompanied by the production
of its antiparticle, whereas in the second scenario it is assumed that the
production of an individual $\PKp$, $\PKm$, $\Pp$, or $\PAp$ is a totally
independent process. The final estimate of the exclusive $\PKp\PKm$ and
$\Pp\PAp$ background normalization is calculated as the average of the
estimates obtained from assuming these two scenarios. According to these
calculations, there is an 11% residual contribution of exclusive $\PKp\PKm$
and $\Pp\PAp$ events in the sample after the multiparticle background
subtraction. The background distributions of this contribution are calculated
by using two-track OS exclusive events with at least one identified $\PKpm$
(Fig. 4).

The estimated multiparticle and exclusive $\PKp\PKm$/$\Pp\PAp$ background
distributions, as functions of the main kinematic variables, are shown in Fig.
4. These two background contributions are subtracted from the measured
distributions. The background subtracted spectra are divided by the integrated
luminosity to obtain the differential cross sections.

###  0.5.4 Systematic uncertainties

Systematic uncertainties in the measured cross sections originate from various
sources. These include reconstruction effects, particle identification,
correction factors, background estimation, and the luminosity estimation. The
uncertainty assigned to the tracking efficiency in the case of a single track
is 3.9% [29], which corresponds to 7.8% uncertainty for two tracks.
Furthermore, the uncertainty in the multiple reconstruction rate for a single
track is also 3.9%, which propagates to a maximum of 0.4% uncertainty in the
cross section for two tracks, which is neglected in the analysis.
Misreconstructed tracks bias the sample in two ways: either a CEP event is
rejected if a third misreconstructed track is found, or an event is identified
as CEP with a misreconstructed and a genuine track. This source of systematic
uncertainty is estimated to be 1% for a single track, which is the maximal
misreconstruction rate calculated using inclusive MC samples in the kinematic
region ($\pt(\PGp)>0.2\GeV$ and $\abs{\eta(\PGp)}<2.4$) of the analysis. Since
the probability to have two or more misreconstructed tracks in these low-
multiplicity events is negligible, the final uncertainty remains 1%. From the
comparison of the dime mc and starlight simulations, the uncertainty of the
vertex correction is estimated to be 1%.

The systematic uncertainty in the pileup correction factor for a single event
is calculated from only the systematic uncertainties in the luminosity
measurement that do not affect its overall normalization. Indeed, the
normalization-related systematic uncertainties are compensated in the
exponential fit described in Section 0.5.2. The uncertainties that do not
affect the normalization are estimated to be 1.6% and 1.5% for 5.02 [44] and
13[45] data, respectively. These values propagate to a 1% uncertainty in the
pileup correction factor for a single event. After adding up all the selected
events, the pileup uncertainty becomes smaller than 0.1%, which is neglected
in the following.

The measured signal yield is affected by the uncertainty arising from the two
effects associated with calorimeter noise and veto inefficiency caused by the
adopted energy thresholds. A genuine CEP event can be erroneously discarded if
the calorimeter noise appears above the energy thresholds used in the veto.
Conversely a nonCEP event can pass the final selection if the extra particles
pass the veto requirements. In the HF, these uncertainties are estimated by
varying the calorimeter energy thresholds by $\pm 10\%$ [46]. The resulting
uncertainty is estimated to be 3% for both the 5.02 and 13data sets.
Similarly, the ECAL and HCAL thresholds are varied by $\pm 5\%$ [47, 48],
which results in a 1% uncertainty in the corrected yields at both energies.

The systematic uncertainty estimation of the multiparticle background is done
by varying the control region used in the background estimation procedure:
1–2, 2–9, and 5–9 extra towers. The estimate of the systematic uncertainty in
the multiparticle background normalization is 10%. Additionally, a 10%
uncertainty is added to this value quadratically, taking into account the
deviations shown in Table 0.5.3; thus the final uncertainty in the
multiparticle background normalization is 14%. After subtracting this
contribution, this propagates to systematic uncertainties depending on the
invariant mass, transverse momentum and rapidity of the pion pair. The
multiparticle background estimation uncertainty varies between 10–20% below
$1500\MeV$. Over $1500\MeV$ the uncertainty varies between 20–60%, because the
signal versus background ratio is much smaller. The average uncertainty, used
as the systematic uncertainty of the total cross section, is 15%.

The exclusive $\PKp\PKm$ and $\Pp\PAp$ background uncertainty comes from three
sources: (i) multiparticle contamination in the $\rd E/\rd x$ vs. momentum
distribution that modifies the $\PK/\PGp$ and $\Pp/\PGp$ ratios, (ii) the
uncertainty in the $\PK/\PGp$ ratio above 1, and (iii) the uncertainty in the
$\Pp/\PGp$ ratio above 2. The multiparticle contamination is estimated by
checking the difference between two extreme cases: all particle types are
produced independently, or the sample is purely exclusive. The results
correspond to an uncertainty of 70% in the normalization of this background
contribution at both energies. To account for the uncertainty of $\PK/\PGp$
above 1and $\Pp/\PGp$ over 2, the exclusive background normalization is
calculated assuming different values (0.25, 0.30, and 0.40 [43]) for the
$\PK/\PGp$ and $\Pp/\PGp$ ratios in these regions. The uncertainties assigned
to these effects are 16 and 4%, respectively. Thus the total systematic
uncertainty of the exclusive $\PKp\PKm$ and $\Pp\PAp$ background normalization
is 72%. After subtracting this background contribution, this propagates to
systematic uncertainties, which depend on the invariant mass, transverse
momentum, and rapidity of the pion pair. The typical range of this systematic
uncertainty contribution is 5–20%. For the total cross section, this source
contributes to an average uncertainty of 6%.

The sources and average values of systematic uncertainties, used as the
systematic uncertainty of the total cross section.  Source Average value
Tracking efficiency 7.8% Misreconstructed tracks 1% Vertex 1% HF energy scale
3% ECAL and HCAL energy scale 1% Multiparticle background 15% Exclusive
$\PKp\PKm$ and $\Pp\PAp$ background 6% Total w/o int. luminosity 18.3% \+
Integrated luminosity 2.3%

All of the systematic uncertainties listed above are the same for the 5.02 and
13data sets. Additionally, the systematic uncertainty in the integrated
luminosity is 2.3% [44, 45]. The average values of the systematic
uncertainties are summarized in Table 0.5.4. The total systematic uncertainty
is obtained by adding the individual contributions in quadrature. All
systematic uncertainty contributions are considered fully correlated across
invariant mass bins.

##  0.6 Results

The differential cross sections are calculated from the selected events as
functions of the invariant mass, transverse momentum, and rapidity of the pion
pair. These are shown in Fig. 5 with the generator-level predictions from the
starlight and dime mc generators, normalized to their cross sections. The MC
generators provide an incomplete description of the available data, since they
do not model the 500, 980, and 1270 resonances as mentioned in Section 0.3.

Figure 5: Differential cross sections as functions of mass (upper row),
transverse momentum (middle row), and rapidity (bottom row), compared with
generator-level simulations for the 5.02 (left) and 13(right) data sets. The
error bars correspond to statistical, whereas the open boxes to systematic
uncertainties.

There is a peak at 800, which corresponds to the $\PGrzP{770}$ resonance.
Since its quantum numbers $I^{G}(J^{PC})=1^{+}(1^{--})$ are forbidden in DPE
processes, the ${\HepParticle{\PGr}{}{0}{}{}{}}$ mesons must be produced in
VMP processes. The sharp drop visible around 1000is expected from previous
measurements [11, 16] and can be attributed to the quantum mechanical
interference of 980 with the continuum contribution. There is a prominent peak
at 1200–1300, which corresponds to the 1270 resonance with
$I^{G}(J^{PC})=0^{+}(2^{++})$ quantum numbers. This resonance is produced via
a DPE process.

Both dime mc and starlight underestimate the measured spectrum as these MC
event generators do not model the forward dissociation of protons.

Figure 6: Fit to the measured cross section with the sum of four interfering
relativistic Breit–Wigner functions convolved with a normal distribution (to
account for the the experimental resolution of the detector) for the 5.02
(left) and 13(right) data sets. The error bars correspond to statistical,
whereas the open boxes correspond to systematic uncertainties.

The total cross section of the CEP process with two pions in the final state
in the kinematic region $\pt(\PGp)>0.2\GeV$ and $\abs{\eta(\PGp)}<2.4$ is
obtained by integrating the observed spectra in this region:

$\displaystyle\sigma_{\Pp\Pp\to\Pp^{\prime}\Pp^{\prime}\PGpp\PGpm}(\sqrt{s}=5.02\TeV)$
$\displaystyle=32.6\pm 0.7\stat\pm 6.0\syst\pm 0.8\lum\,\mu\text{b},$ (9)
$\displaystyle\sigma_{\Pp\Pp\to\Pp^{\prime}\Pp^{\prime}\PGpp\PGpm}(\sqrt{s}=13\TeV)$
$\displaystyle=33.7\pm 1.0\stat\pm 6.2\syst\pm 0.8\lum\,\mu\text{b}.$ (10)

Below, it is demonstrated that the measured invariant $\PGpp\PGpm$ mass
spectrum is well-described by the sum of the continuum distributions obtained
from the dime mc model and four dominant resonances, modeled here by Breit-
Wigner functions. In the fitting procedure the quantum mechanical interference
effect and the detector resolution are also included.

The following fit function is used:

$f(m)=\int
G(m-m^{\prime};\sigma)\Big{[}\abs{A_{\text{RBW}}^{{\HepParticle{\PGr}{}{0}{}{}{}}}(m^{\prime})}^{2}+\abs{A_{\text{RBW}}^{\PfDzP{500}}(m^{\prime})\re^{\mathrm{i}\phi^{\PfDzP{500}}m^{\prime}}+A_{\mathrm{RBW}}^{\PfDzP{980}}(m^{\prime})\re^{\mathrm{i}\phi^{\PfDzP{980}}m^{\prime}}\\\
+A_{\text{RBW}}^{\mathrm{f}_{2}}(m^{\prime})\re^{\mathrm{i}\phi^{\mathrm{f}_{2}}m^{\prime}}+b\,B^{\textsc{dime}}(m^{\prime})}^{2}\Big{]}\rd
m^{\prime}.$ (11)

Here $G(m;\sigma)$ is a Gaussian distribution with variance $\sigma$ and zero
mean, $B^{\textsc{dime}}(m)$ is the nonresonant background estimated from the
dime mc using the Orear-type form factor, and $b$ is a scale factor for the
continuum contribution, and $\phi^{\PfDzP{500}}$, $\phi^{\PfDzP{980}}$, and
$\phi^{\mathrm{f}_{2}}$ are phases that characterize interference effects. The
$A_{\text{RBW}}^{i}(m)$ is the relativistic Breit–Wigner amplitude, which can
be written as [49]:

$\displaystyle A_{\text{RBW}}^{i,J}(m)$
$\displaystyle=A_{i}\frac{\sqrt{mM_{i}\Gamma(m)}}{m^{2}-M_{i}^{2}+iM_{i}\Gamma(m)},$
(12) $\displaystyle\Gamma(m)$
$\displaystyle=\Gamma_{i}\frac{M_{i}}{m}\left[\frac{m^{2}-4m_{\PGp}^{2}}{M_{i}^{2}-4m_{\PGp}^{2}}\right]^{\frac{2J+1}{2}},$
(13)

where $A_{i}$, $M_{i}$, and $\Gamma_{i}$ are the yield, mass, and width of the
resonance, respectively, $m_{\PGp}$ is the mass of charged pions, and $J$ is
the total angular momentum of the resonance. According to Ref. [2], the
magnitude of the interference between the DPE and VMP processes is around 1%,
therefore no interference term is used between
${\HepParticle{\PGr}{}{0}{}{}{}}$ and DPE resonances. The convolution with the
Gaussian distribution models the mass resolution of the detector.

The mass resolution ($\sigma$) is calculated by fitting the distribution of
the difference between generator-level and reconstructed mass from the
starlight and dime mc simulations. Based on these calculations, the mass
resolution is found to vary from 9 to 14in the mass range 500–2000. In the
final fit, an effective mass resolution of 11is used and the systematic
uncertainty associated with this value is taken into account by repeating the
fit with a mass resolution varying from 9 to 14. The resulting systematic
uncertainty is 7–8% for the yield of 980 and around 1–2% for the yields of the
500, 770, and 1270 resonances. The impact of the uncertainty in the
multiparticle (exclusive $\PKp\PKm$ and $\Pp\PAp$) background yield is
included by varying the background normalization in the fit by $\pm 14\%$
($\pm 72\%$).

Cross sections of the resonant processes in the
$\pt(\PGp)>0.2\GeV,\abs{\eta(\PGp)}<2.4$ fiducial region, extracted from the
simple model fit using the sum of the continuum distribution obtained from the
dime mc model and four dominant resonances. The luminosity-related
uncertainties are included in the systematic uncertainties. The starlight
predictions for
$\Pp\Pp\to\Pp^{\prime}\Pp^{\prime}{\HepParticle{\PGr}{}{0}{}{}{}}\to\Pp^{\prime}\Pp^{\prime}\PGpp\PGpm$
processes are 2.3 and 3.0$\,\mu\text{b}$ for 5.02 and 13, respectively, which
is compatible with the fit results.  Resonance
$\sigma_{\Pp\Pp\to\Pp^{\prime}\Pp^{\prime}X\to\Pp^{\prime}\Pp^{\prime}\PGpp\PGpm}[\mu\mathrm{b}]$
$\sqrt{s}=5.02\TeV$ $\sqrt{s}=13\TeV$ 500 $2.8\pm 1.4\stat\pm 2.2\syst$
$2.2\pm 0.8\stat\pm 1.3\syst$ $\PGrzP{770}$ $4.7\pm 0.9\stat\pm 1.3\syst$
$4.3\pm 1.3\stat\pm 1.5\syst$ 980 $0.5\pm 0.1\stat\pm 0.1\syst$ $1.1\pm
0.4\stat\pm 0.3\syst$ 1270 $3.6\pm 0.6\stat\pm 0.7\syst$ $4.2\pm 0.9\stat\pm
0.8\syst$

The masses and widths of 770 and 1270 resonances are fixed to the values of
Ref. [24]. The mass and width of 500 and 980 are fixed according to the
results from the most advanced calculations using dispersion relations [50].

The fits are also performed with the mass and width of 500 and 980 varied
according to their uncertainties [24] and the resulting variation in the cross
section of the resonances is added in quadrature to the other systematic
uncertainty contributions. Furthermore the fit is repeated with the two other
dime mc settings and the variation in the cross section is taken as an
additional systematic uncertainty and added in quadrature to the other
uncertainties.

The above simple model fit also provides values for the cross sections of the
resonances; these are obtained by integrating the fitted squared amplitudes
from the dipion threshold ($2m_{\PGp}$) to $M_{i}+5\Gamma_{i}$:

$\sigma^{\text{res}}_{i}=\int_{2m_{\PGp}}^{M_{i}+5\Gamma_{i}}\abs{A^{2}_{\text{RBW},i}(m)}\rd
m.$ (14)

The fits are shown in Fig. 6 and the cross sections are summarized in Table
0.6.

The model of interfering Breit–Wigner resonances with a continuum gives a good
description of the data in the region of resonant peaks (below 1500). The
cross sections for $\PGrzP{770}$ production calculated from the fits are
slightly larger than the predicted values from starlight, which are 2.3 and
3.0$\,\mu\text{b}$ for 5.02 and 13, respectively. The differences can be
attributed to the additional semiexclusive contribution that is not modeled by
starlight. The values of the scale parameter $b$ are $0.7\pm 0.2$ for 5.02and
$1.1\pm 0.3$ for 13, and therefore they are consistent within uncertainties
for the two energies.

##  0.7 Summary

The cross sections for central exclusive pion pair production have been
measured in $\Pp\Pp$ collisions at 5.02 and 13center-of-mass energies.
Exclusive events are selected by vetoing additional energy deposits in the
calorimeters and by requiring two oppositely charged pions identified via
their mean energy loss in the tracker detectors. These events are used
together with correction factors to obtain invariant mass, transverse
momentum, and rapidity distributions of the $\PGpp\PGpm$ system. The measured
total exclusive $\PGpp\PGpm$ production cross section is $32.6\pm 0.7\stat\pm
6.0\syst\pm 0.8\lum$ and $33.7\pm 1.0\stat\pm 6.2\syst\pm
0.8\lum$$\,\mu\text{b}$ for 5.02 and 13, respectively. The observed mass
spectrum exhibits resonant structures, which can be fitted with a simple model
containing four interfering Breit-Wigner functions, corresponding to the 500,
$\PGrzP{770}$, 980, and 1270 resonances, and a continuum contribution modeled
by the dime mc. The exclusive production cross sections are extracted from
this fit. The obtained cross sections of $\PGrzP{770}$ production are higher
than the starlight model prediction, which can be explained by the presence of
semiexclusive production which is not modeled by the starlight generator.

###### 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 centers 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, PUT 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 (Ukraine); STFC (United Kingdom); DOE and NSF (USA).
Individuals have received support from the Marie-Curie program and the
European Research Council and Horizon 2020 Grant, contract Nos. 675440,
752730, and 765710 (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
Beijing Municipal Science & Technology Commission, No. Z191100007219010; the
Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the
Deutsche Forschungsgemeinschaft (DFG) under Germany’s Excellence Strategy –
EXC 2121 “Quantum Universe” – 390833306; the Lendület (“Momentum”) Program 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, 125105, 128713, 128786, and 129058 (Hungary); the
Council of Science and Industrial Research, India; the HOMING PLUS program of
the Foundation for Polish Science, cofinanced from European Union, Regional
Development Fund, the Mobility Plus program 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 Ministry of Science and
Education, grant no. 14.W03.31.0026 (Russia); the Tomsk Polytechnic University
Competitiveness Enhancement Program and “Nauka” Project FSWW-2020-0008
(Russia); 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 programs
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
Kavli Foundation; the Nvidia Corporation; the SuperMicro Corporation; the
Welch Foundation, contract C-1845; and the Weston Havens Foundation (USA).

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##  .8 The CMS Collaboration

Yerevan Physics Institute, Yerevan, Armenia
A.M. Sirunyan${}^{\textrm{\textdagger}}$, A. Tumasyan Institut für
Hochenergiephysik, Wien, Austria
W. Adam, F. Ambrogi, T. Bergauer, J. Brandstetter, M. Dragicevic, J. Erö, A.
Escalante Del Valle, M. Flechl, R. Frühwirth1, M. Jeitler1, N. Krammer, I.
Krätschmer, D. Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck1, R.
Schöfbeck, M. Spanring, D. Spitzbart, W. Waltenberger, J. Wittmann, C.-E.
Wulz1, M. Zarucki Institute for Nuclear Problems, Minsk, Belarus
V. Drugakov, V. Mossolov, J. Suarez Gonzalez Universiteit Antwerpen,
Antwerpen, Belgium
M.R. Darwish, E.A. De Wolf, D. Di Croce, X. Janssen, J. Lauwers, A. Lelek, M.
Pieters, H. Rejeb Sfar, H. Van Haevermaet, P. Van Mechelen, S. Van Putte, N.
Van Remortel Vrije Universiteit Brussel, Brussel, Belgium
F. Blekman, E.S. Bols, S.S. Chhibra, J. D’Hondt, J. De Clercq, 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, L. Favart, A. Grebenyuk, A.K. Kalsi, J. Luetic, A. Popov, N. Postiau,
E. Starling, L. Thomas, C. Vander Velde, P. Vanlaer, D. Vannerom, Q. Wang
Ghent University, Ghent, Belgium
T. Cornelis, D. Dobur, I. Khvastunov2, C. Roskas, D. Trocino, M. Tytgat, W.
Verbeke, B. Vermassen, M. Vit, N. Zaganidis Université Catholique de Louvain,
Louvain-la-Neuve, Belgium
O. Bondu, G. Bruno, C. Caputo, P. David, C. Delaere, M. Delcourt, A.
Giammanco, G. Krintiras, V. Lemaitre, A. Magitteri, K. Piotrzkowski, J.
Prisciandaro, A. Saggio, M. Vidal Marono, P. Vischia, J. Zobec Centro
Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil
F.L. Alves, G.A. Alves, G. Correia Silva, C. Hensel, A. Moraes, 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, L.M. Huertas Guativa, H. Malbouisson, J. Martins5, D. Matos
Figueiredo, M. Medina Jaime6, 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, D.S. Lemos, P.G. Mercadanteb, S.F. Novaesa, SandraS. Padulaa
Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of
Sciences, Sofia, Bulgaria
A. Aleksandrov, G. Antchev, 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. Fang7, X. Gao7, L. Yuan Department of Physics, Tsinghua University,
Beijing, China
Z. Hu, Y. Wang Institute of High Energy Physics, Beijing, China
M. Ahmad, G.M. Chen, H.S. Chen, M. Chen, C.H. Jiang, D. Leggat, H. Liao, Z.
Liu, S.M. Shaheen8, A. Spiezia, J. Tao, E. Yazgan, H. Zhang, S. Zhang8, J.
Zhao State Key Laboratory of Nuclear Physics and Technology, Peking
University, Beijing, China
A. Agapitos, Y. Ban, G. Chen, A. Levin, J. Li, L. Li, Q. Li, Y. Mao, S.J.
Qian, D. Wang Universidad de Los Andes, Bogota, Colombia
C. Avila, A. Cabrera, 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
D. Giljanović, 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, S. Ceci, D. Ferencek, K. Kadija, B. Mesic, M. Roguljic, A.
Starodumov9, T. Susa University of Cyprus, Nicosia, Cyprus
M.W. Ather, A. Attikis, E. Erodotou, A. Ioannou, M. Kolosova, S. Konstantinou,
G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis, H.
Rykaczewski, D. Tsiakkouri Charles University, Prague, Czech Republic
M. Finger10, M. Finger Jr.10, A. Kveton, J. Tomsa 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
M.A. Mahmoud11,12, Y. Mohammed11 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, L. Forthomme, H. Kirschenmann, K. Osterberg, J. Pekkanen, M.
Voutilainen Helsinki Institute of Physics, Helsinki, Finland
F. Garcia, 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, B. Fabbro, J.L. Faure, F.
Ferri, S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry,
C. Leloup, E. Locci, J. Malcles, J. Rander, A. Rosowsky, M.Ö. Sahin, A. Savoy-
Navarro13, M. Titov Laboratoire Leprince-Ringuet, CNRS/IN2P3, Ecole
Polytechnique, Institut Polytechnique de Paris
C. Amendola, F. Beaudette, P. Busson, C. Charlot, B. Diab, R. Granier de
Cassagnac, I. Kucher, A. Lobanov, C. Martin Perez, M. Nguyen, C. Ochando, P.
Paganini, J. Rembser, R. Salerno, J.B. Sauvan, Y. Sirois, A. Zabi, A. Zghiche
Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
J.-L. Agram14, J. Andrea, D. Bloch, G. Bourgatte, J.-M. Brom, E.C. Chabert, C.
Collard, E. Conte14, J.-C. Fontaine14, 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, C. Camen, N. Chanon, R. Chierici, D.
Contardo, P. Depasse, H. El Mamouni, J. Fay, S. Gascon, M. Gouzevitch, B.
Ille, Sa. Jain, F. Lagarde, I.B. Laktineh, H. Lattaud, M. Lethuillier, L.
Mirabito, S. Perries, V. Sordini, G. Touquet, M. Vander Donckt, S. Viret
Georgian Technical University, Tbilisi, Georgia
T. Toriashvili15 Tbilisi State University, Tbilisi, Georgia
Z. Tsamalaidze10 RWTH Aachen University, I. Physikalisches Institut, Aachen,
Germany
C. Autermann, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, D. Meuser, A.
Pauls, M. Preuten, M.P. Rauch, C. Schomakers, J. Schulz, M. Teroerde, B.
Wittmer RWTH Aachen University, III. Physikalisches Institut A, Aachen,
Germany
A. Albert, M. Erdmann, S. Erdweg, T. Esch, B. Fischer, R. Fischer, S. Ghosh,
T. Hebbeker, K. Hoepfner, H. Keller, L. Mastrolorenzo, M. Merschmeyer, A.
Meyer, P. Millet, G. Mocellin, S. Mondal, S. Mukherjee, D. Noll, A. Novak, T.
Pook, A. Pozdnyakov, T. Quast, M. Radziej, Y. Rath, H. Reithler, M. Rieger, A.
Schmidt, S.C. Schuler, A. Sharma, S. Thüer, S. Wiedenbeck RWTH Aachen
University, III. Physikalisches Institut B, Aachen, Germany
G. Flügge, W. Haj Ahmad16, O. Hlushchenko, T. Kress, T. Müller, A. Nehrkorn,
A. Nowack, C. Pistone, O. Pooth, D. Roy, H. Sert, A. Stahl17 Deutsches
Elektronen-Synchrotron, Hamburg, Germany
M. Aldaya Martin, C. Asawatangtrakuldee, P. Asmuss, I. Babounikau, H.
Bakhshiansohi, K. Beernaert, O. Behnke, U. Behrens, A. Bermúdez Martínez, D.
Bertsche, A.A. Bin Anuar, K. Borras18, V. Botta, A. Campbell, A. Cardini, P.
Connor, S. Consuegra Rodríguez, C. Contreras-Campana, V. Danilov, A. De Wit,
M.M. Defranchis, C. Diez Pardos, D. Domínguez Damiani, G. Eckerlin, D.
Eckstein, T. Eichhorn, A. Elwood, E. Eren, E. Gallo19, A. Geiser, J.M. Grados
Luyando, A. Grohsjean, M. Guthoff, M. Haranko, A. Harb, N.Z. Jomhari, H. Jung,
A. Kasem18, M. Kasemann, J. Keaveney, C. Kleinwort, J. Knolle, D. Krücker, W.
Lange, T. Lenz, J. Leonard, J. Lidrych, K. Lipka, W. Lohmann20, R. Mankel,
I.-A. Melzer-Pellmann, A.B. Meyer, M. Meyer, M. Missiroli, G. Mittag, J.
Mnich, A. Mussgiller, V. Myronenko, D. Pérez Adán, S.K. Pflitsch, D. Pitzl, A.
Raspereza, A. Saibel, M. Savitskyi, V. Scheurer, P. Schütze, C.
Schwanenberger, R. Shevchenko, A. Singh, H. Tholen, O. Turkot, A. Vagnerini,
M. Van De Klundert, G.P. Van Onsem, R. Walsh, Y. Wen, K. Wichmann, C. Wissing,
O. Zenaiev, R. Zlebcik University of Hamburg, Hamburg, Germany
R. Aggleton, S. Bein, L. Benato, A. Benecke, V. Blobel, T. Dreyer, A.
Ebrahimi, A. Fröhlich, C. Garbers, 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, T. Lange, A. Malara, 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, T. Berger, E. Butz, R. Caspart, T.
Chwalek, W. De Boer, A. Dierlamm, K. El Morabit, N. Faltermann, M. Giffels, P.
Goldenzweig, A. Gottmann, M.A. Harrendorf, F. Hartmann17, U. Husemann, S.
Kudella, S. Mitra, M.U. Mozer, Th. Müller, M. Musich, A. Nürnberg, G. Quast,
K. Rabbertz, M. Schröder, I. Shvetsov, H.J. Simonis, R. Ulrich, M. Weber, C.
Wöhrmann, R. Wolf Institute of Nuclear and Particle Physics (INPP), NCSR
Demokritos, Aghia Paraskevi, Greece
G. Anagnostou, P. Asenov, G. Daskalakis, T. Geralis, A. Kyriakis, D. Loukas,
G. Paspalaki National and Kapodistrian University of Athens, Athens, Greece
M. Diamantopoulou, G. Karathanasis, P. Kontaxakis, A. Panagiotou, I.
Papavergou, N. Saoulidou, A. Stakia, K. Theofilatos, K. Vellidis National
Technical University of Athens, Athens, Greece
G. Bakas, K. Kousouris, I. Papakrivopoulos, G. Tsipolitis University of
Ioánnina, Ioánnina, Greece
I. Evangelou, C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios, K.
Manitara, N. Manthos, I. Papadopoulos, J. Strologas, F.A. Triantis, D.
Tsitsonis MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary
M. Bartók21, M. Csanad, P. Major, K. Mandal, A. Mehta, M.I. Nagy, G. Pasztor,
O. Surányi, G.I. Veres Wigner Research Centre for Physics, Budapest, Hungary
G. Bencze, C. Hajdu, D. Horvath22, F. Sikler, T.Á. Vámi, V. Veszpremi, G.
Vesztergombi${}^{\textrm{\textdagger}}$ Institute of Nuclear Research ATOMKI,
Debrecen, Hungary
N. Beni, S. Czellar, J. Karancsi21, A. Makovec, J. Molnar, Z. Szillasi
Institute of Physics, University of Debrecen, Debrecen, Hungary
P. Raics, D. Teyssier, Z.L. Trocsanyi, B. Ujvari Eszterhazy Karoly University,
Karoly Robert Campus, Gyongyos, Hungary
T.F. Csorgo, W.J. Metzger, F. Nemes, T. Novak 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. Bahinipati24, C. Kar, G. Kole, P. Mal, V.K. Muraleedharan Nair Bindhu, A.
Nayak25, S. Roy Chowdhury, D.K. Sahoo24, 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, 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. Bhardwaj26, M. Bharti26, R. Bhattacharya, S. Bhattacharya, U. Bhawandeep26,
D. Bhowmik, S. Dey, S. Dutta, S. Ghosh, M. Maity27, K. Mondal, S. Nandan, A.
Purohit, P.K. Rout, A. Roy, G. Saha, S. Sarkar, T. Sarkar27, M. Sharan, B.
Singh26, S. Thakur26 Indian Institute of Technology Madras, Madras, India
P.K. Behera, P. Kalbhor, A. Muhammad, P.R. Pujahari, A. Sharma, A.K. Sikdar
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, RavindraKumar Verma Tata
Institute of Fundamental Research-B, Mumbai, India
S. Banerjee, S. Bhattacharya, S. Chatterjee, P. Das, M. Guchait, S. Karmakar,
S. Kumar, G. Majumder, K. Mazumdar, N. Sahoo, S. Sawant 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. Chenarani28, E. Eskandari Tadavani, S.M. Etesami28, M. Khakzad, M.
Mohammadi Najafabadi, M. Naseri, F. Rezaei Hosseinabadi 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, 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, 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,
C. Cioccaa, 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,29, S. Marcellinia, G. Masettia, F.L. Navarriaa,b, A.
Perrottaa, F. Primaveraa,b, 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,30, S. Costaa,b, A. Di Mattiaa, R. Potenzaa,b, A. Tricomia,b,30,
C. Tuvea,b INFN Sezione di Firenze a, Università di Firenze b, Firenze, Italy
G. Barbaglia, R. Ceccarellia,b, 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,31, G. Sguazzonia, D. Stroma, L. Viliania INFN Laboratori
Nazionali di Frascati, Frascati, Italy
L. Benussi, S. Bianco, D. Piccolo INFN Sezione di Genova a, Università di
Genova b, Genova, Italy
M. Bozzoa,b, F. Ferroa, R. Mulargiaa,b, E. Robuttia, S. Tosia,b INFN Sezione
di Milano-Bicocca a, Università di Milano-Bicocca b, Milano, Italy
A. Benagliaa, A. Beschia,b, F. Brivioa,b, V. Cirioloa,b,17, S. Di Guidaa,b,17,
M.E. Dinardoa,b, P. Dinia, S. Fiorendia,b, S. Gennaia, A. Ghezzia,b, P.
Govonia,b, L. Guzzia,b, M. Malbertia, S. Malvezzia, D. Menascea, F. Montia,b,
L. Moronia, G. Ortonaa,b, 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, L. Listaa,b, S.
Meolaa,d,17, P. Paoluccia,17, B. Rossia, 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, P. De Castro Manzanoa, T. Dorigoa, U. Dossellia, F.
Gasparinia,b, U. Gasparinia,b, A. Gozzelinoa, S.Y. Hoh, 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, 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, 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, V. Bertacchia,c, L. Bianchinia, T.
Boccalia, 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. Rolandi32, A.
Scribanoa, P. Spagnoloa, R. Tenchinia, G. Tonellia,b, N. Turinia, A. Venturia,
P.G. Verdinia INFN Sezione di Roma a, Sapienza Università di Roma b, Rome,
Italy
F. Cavallaria, M. Cipriania,b, D. Del Rea,b, E. Di Marcoa,b, M. Diemoza, E.
Longoa,b, B. Marzocchia,b, P. Meridiania, G. Organtinia,b, F. Pandolfia, R.
Paramattia,b, C. Quarantaa,b, S. Rahatloua,b, C. Rovellia, F.
Santanastasioa,b, L. Soffia,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, 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
B. Kim, D.H. Kim, G.N. Kim, M.S. Kim, J. 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, T.J. Kim, J. Park Korea University, Seoul, Korea
S. Cho, S. Choi, Y. Go, D. Gyun, S. Ha, B. Hong, K. Lee, K.S. Lee, J. Lim, J.
Park, S.K. Park, Y. Roh Kyung Hee University, Department of Physics
J. Goh Sejong University, Seoul, Korea
H.S. Kim Seoul National University, Seoul, Korea
J. Almond, J.H. Bhyun, J. Choi, S. Jeon, J. Kim, J.S. Kim, H. Lee, K. Lee, S.
Lee, K. Nam, S.B. Oh, B.C. Radburn-Smith, S.h. Seo, U.K. Yang, H.D. Yoo, I.
Yoon, G.B. Yu University of Seoul, Seoul, Korea
D. Jeon, H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, I. Watson Sungkyunkwan
University, Suwon, Korea
Y. Choi, C. Hwang, Y. Jeong, J. Lee, Y. Lee, I. Yu Riga Technical University,
Riga, Latvia
V. Veckalns33 Vilnius University, Vilnius, Lithuania
V. Dudenas, A. Juodagalvis, J. Vaitkus National Centre for Particle Physics,
Universiti Malaya, Kuala Lumpur, Malaysia
Z.A. Ibrahim, F. Mohamad Idris34, 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, L. Valencia Palomo
Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-De La Cruz35, R. Lopez-
Fernandez, A. Sanchez-Hernandez Universidad Iberoamericana, Mexico City,
Mexico
S. Carrillo Moreno, C. Oropeza Barrera, M. Ramirez-Garcia, 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 Montenegro, Podgorica, Montenegro
N. Raicevic 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, Q. Hassan, H.R. Hoorani, W.A. Khan, M.A. Shah, M. Shoaib,
M. Waqas AGH University of Science and Technology Faculty of Computer Science,
Electronics and Telecommunications, Krakow, Poland
V. Avati, L. Grzanka, M. Malawski National Centre for Nuclear Research,
Swierk, Poland
H. Bialkowska, M. Bluj, B. Boimska, M. Górski, M. Kazana, M. Szleper, P.
Zalewski Institute of Experimental Physics, Faculty of Physics, University of
Warsaw, Warsaw, Poland
K. Bunkowski, A. Byszuk36, 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, D. Bastos, 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. Matveev37,38, P. Moisenz, V. Palichik,
V. Perelygin, M. Savina, S. Shmatov, S. Shulha, N. Skatchkov, V. Smirnov, N.
Voytishin, A. Zarubin Petersburg Nuclear Physics Institute, Gatchina (St.
Petersburg), Russia
L. Chtchipounov, V. Golovtsov, Y. Ivanov, V. Kim39, E. Kuznetsova40, P.
Levchenko, V. Murzin, V. Oreshkin, I. Smirnov, D. Sosnov, V. Sulimov, L.
Uvarov, 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 named by A.I. Alikhanov of NRC ‘Kurchatov Institute’,
Moscow, Russia
V. Epshteyn, V. Gavrilov, N. Lychkovskaya, A. Nikitenko41, V. Popov, I.
Pozdnyakov, G. Safronov, A. Spiridonov, A. Stepennov, 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
M. Chadeeva42, D. Philippov, E. Popova, V. Rusinov P.N. Lebedev Physical
Institute, Moscow, Russia
V. Andreev, M. Azarkin, I. Dremin38, M. Kirakosyan, A. Terkulov Skobeltsyn
Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow,
Russia
A. Belyaev, E. Boos, A. Ershov, A. Gribushin, L. Khein, V. Klyukhin, O.
Kodolova, I. Lokhtin, O. Lukina, S. Obraztsov, S. Petrushanko, V. Savrin, A.
Snigirev Novosibirsk State University (NSU), Novosibirsk, Russia
A. Barnyakov43, V. Blinov43, T. Dimova43, L. Kardapoltsev43, Y. Skovpen43
Institute for High Energy Physics of National Research Centre ‘Kurchatov
Institute’, Protvino, Russia
I. Azhgirey, I. Bayshev, S. Bitioukov, V. Kachanov, 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, A. Iuzhakov, V. Okhotnikov Tomsk State University, Tomsk, Russia
V. Borchsh, V. Ivanchenko, E. Tcherniaev University of Belgrade: Faculty of
Physics and VINCA Institute of Nuclear Sciences
P. Adzic44, P. Cirkovic, D. Devetak, M. Dordevic, P. Milenovic, J. Milosevic,
M. Stojanovic Centro de Investigaciones Energéticas Medioambientales y
Tecnológicas (CIEMAT), Madrid, Spain
M. Aguilar-Benitez, J. Alcaraz Maestre, A. Álvarez Fernández, I. Bachiller, M.
Barrio Luna, J.A. Brochero Cifuentes, C.A. Carrillo Montoya, M. Cepeda, 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, Á. Navarro Tobar, A. Pérez-Calero Yzquierdo,
J. Puerta Pelayo, I. Redondo, L. Romero, S. Sánchez Navas, M.S. Soares, A.
Triossi, C. Willmott Universidad Autónoma de Madrid, Madrid, Spain
C. Albajar, J.F. de Trocóniz Universidad de Oviedo, Instituto Universitario de
Ciencias y Tecnologías Espaciales de Asturias (ICTEA), Oviedo, Spain
B. Alvarez Gonzalez, 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 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, G. Gomez, 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, J.M. Vizan
Garcia University of Colombo, Colombo, Sri Lanka
D.U.J. Sonnadara University of Ruhuna, Department of Physics, Matara, Sri
Lanka
W.G.D. Dharmaratna, N. Wickramage CERN, European Organization for Nuclear
Research, Geneva, Switzerland
D. Abbaneo, B. Akgun, E. Auffray, G. Auzinger, J. Baechler, P. Baillon, A.H.
Ball, D. Barney, J. Bendavid, M. Bianco, A. Bocci, E. Bossini, C. Botta, E.
Brondolin, T. Camporesi, A. Caratelli, G. Cerminara, E. Chapon, G. Cucciati,
D. d’Enterria, A. Dabrowski, N. Daci, V. Daponte, A. David, A. De Roeck, N.
Deelen, M. Deile, M. Dobson, M. Dünser, N. Dupont, A. Elliott-Peisert, F.
Fallavollita45, D. Fasanella, G. Franzoni, J. Fulcher, W. Funk, S. Giani, D.
Gigi, A. Gilbert, K. Gill, F. Glege, M. Gruchala, M. Guilbaud, D. Gulhan, J.
Hegeman, C. Heidegger, Y. Iiyama, V. Innocente, A. Jafari, P. Janot, O.
Karacheban20, J. Kaspar, J. Kieseler, M. Krammer1, C. Lange, P. Lecoq, C.
Lourenço, L. Malgeri, M. Mannelli, A. Massironi, F. Meijers, J.A. Merlin, S.
Mersi, E. Meschi, F. Moortgat, M. Mulders, J. Ngadiuba, S. Nourbakhsh, S.
Orfanelli, L. Orsini, F. Pantaleo17, L. Pape, E. Perez, M. Peruzzi, A.
Petrilli, G. Petrucciani, A. Pfeiffer, M. Pierini, F.M. Pitters, M. Quinto, D.
Rabady, A. Racz, M. Rovere, H. Sakulin, C. Schäfer, C. Schwick, M. Selvaggi,
A. Sharma, P. Silva, W. Snoeys, P. Sphicas46, J. Steggemann, V.R. Tavolaro, D.
Treille, A. Tsirou, A. Vartak, M. Verzetti, W.D. Zeuner Paul Scherrer
Institut, Villigen, Switzerland
L. Caminada47, 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, 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, F. Pauss, G. Perrin, L. Perrozzi, S. Pigazzini, M.
Reichmann, C. Reissel, T. Reitenspiess, D. Ruini, D.A. Sanz Becerra, M.
Schönenberger, L. Shchutska, M.L. Vesterbacka Olsson, R. Wallny, D.H. Zhu
Universität Zürich, Zurich, Switzerland
T.K. Aarrestad, C. Amsler48, D. Brzhechko, M.F. Canelli, A. De Cosa, R. Del
Burgo, S. Donato, C. Galloni, B. Kilminster, S. Leontsinis, V.M. Mikuni, I.
Neutelings, G. Rauco, P. Robmann, D. Salerno, K. Schweiger, C. Seitz, Y.
Takahashi, S. Wertz, A. Zucchetta National Central University, Chung-Li,
Taiwan
T.H. Doan, C.M. Kuo, W. Lin, S.S. Yu National Taiwan University (NTU), Taipei,
Taiwan
P. Chang, Y. Chao, K.F. Chen, P.H. Chen, W.-S. Hou, Y.y. Li, 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
M.N. Bakirci49, A. Bat, F. Boran, S. Damarseckin50, Z.S. Demiroglu, F. Dolek,
C. Dozen, I. Dumanoglu, E. Eskut, G. Gokbulut, EmineGurpinar Guler51, Y.
Guler, I. Hos52, C. Isik, E.E. Kangal53, O. Kara, A. Kayis Topaksu, U.
Kiminsu, M. Oglakci, G. Onengut, K. Ozdemir54, A.E. Simsek, D. Sunar Cerci55,
U.G. Tok, S. Turkcapar, I.S. Zorbakir, C. Zorbilmez Middle East Technical
University, Physics Department, Ankara, Turkey
B. Isildak56, G. Karapinar57, M. Yalvac Bogazici University, Istanbul, Turkey
I.O. Atakisi, E. Gülmez, M. Kaya58, O. Kaya59, B. Kaynak, Ö. Özçelik, S.
Ozkorucuklu60, S. Tekten, E.A. Yetkin61 Istanbul Technical University,
Istanbul, Turkey
A. Cakir, K. Cankocak, Y. Komurcu, S. Sen62 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, E. Bhal, S. Bologna, J.J. Brooke, D. Burns, E. Clement, D. Cussans,
O. Davignon, H. Flacher, J. Goldstein, G.P. Heath, H.F. Heath, L. Kreczko, S.
Paramesvaran, B. Penning, T. Sakuma, S. Seif El Nasr-Storey, 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, D.M. Newbold, E.
Olaiya, D. Petyt, T. Reis, T. Schuh, 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,
GurpreetSingh CHAHAL64, D. Colling, P. Dauncey, G. Davies, M. Della Negra, R.
Di Maria, P. Everaerts, G. Hall, G. Iles, T. James, M. Komm, C. Laner, L.
Lyons, A.-M. Magnan, S. Malik, A. Martelli, V. Milosevic, J. Nash65, V.
Palladino, M. Pesaresi, D.M. Raymond, A. Richards, A. Rose, E. Scott, C. Seez,
A. Shtipliyski, M. Stoye, T. Strebler, S. Summers, A. Tapper, K. Uchida, T.
Virdee17, N. Wardle, D. Winterbottom, J. Wright, A.G. Zecchinelli, 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, C. Madrid, B. McMaster, N. Pastika, C.
Smith Catholic University of America, Washington, DC, USA
R. Bartek, A. Dominguez, R. Uniyal 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, Z. Demiragli, D. Gastler, S. Girgis, D. Pinna, C.
Richardson, J. Rohlf, D. Sperka, I. Suarez, L. Sulak, D. Zou Brown University,
Providence, USA
G. Benelli, B. Burkle, X. Coubez, D. Cutts, M. Hadley, J. Hakala, U. Heintz,
J.M. Hogan66, K.H.M. Kwok, E. Laird, G. Landsberg, J. Lee, Z. Mao, M. Narain,
S. Sagir67, R. Syarif, E. Usai, D. Yu University of California, Davis, Davis,
USA
R. Band, C. Brainerd, R. Breedon, M. Calderon De La Barca Sanchez, M. Chertok,
J. Conway, R. Conway, P.T. Cox, R. Erbacher, C. Flores, G. Funk, F. Jensen, W.
Ko, O. Kukral, R. Lander, M. Mulhearn, D. Pellett, J. Pilot, 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
K. Burt, R. Clare, J.W. Gary, S.M.A. Ghiasi Shirazi, G. Hanson, G.
Karapostoli, E. Kennedy, O.R. Long, M. Olmedo Negrete, M.I. Paneva, W. Si, L.
Wang, H. Wei, S. Wimpenny, B.R. Yates, Y. Zhang University of California, San
Diego, La Jolla, USA
J.G. Branson, P. Chang, S. Cittolin, M. Derdzinski, R. Gerosa, D. Gilbert, B.
Hashemi, D. Klein, V. Krutelyov, J. Letts, M. Masciovecchio, S. May, S. Padhi,
M. Pieri, V. Sharma, M. Tadel, 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, J. Incandela, B. Marsh, H. Mei, A. Ovcharova, H. Qu, J. Richman,
U. Sarica, D. Stuart, 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, J.
Pata, M. Spiropulu, J.R. Vlimant, 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, 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, A. Frankenthal, K.
Mcdermott, N. Mirman, J.R. Patterson, D. Quach, A. Rinkevicius68, A. Ryd, S.M.
Tan, Z. Tao, J. Thom, 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, AllisonReinsvold Hall, J. Hanlon, R.M.
Harris, S. Hasegawa, R. Heller, J. Hirschauer, B. Jayatilaka, S. Jindariani,
M. Johnson, U. Joshi, B. Klima, M.J. Kortelainen, B. Kreis, S. Lammel, J.
Lewis, 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, V.
Papadimitriou, K. Pedro, C. Pena, G. Rakness, F. Ravera, L. Ristori, B.
Schneider, E. Sexton-Kennedy, N. Smith, 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
University of Florida, Gainesville, USA
D. Acosta, P. Avery, P. Bortignon, D. Bourilkov, A. Brinkerhoff, L. Cadamuro,
A. Carnes, V. Cherepanov, D. Curry, F. Errico, R.D. Field, S.V. Gleyzer, B.M.
Joshi, M. Kim, J. Konigsberg, A. Korytov, K.H. Lo, P. Ma, K. Matchev, N.
Menendez, G. Mitselmakher, D. Rosenzweig, K. Shi, J. Wang, S. Wang, X. Zuo
Florida International University, Miami, USA
Y.R. Joshi Florida State University, Tallahassee, USA
T. Adams, A. Askew, S. Hagopian, V. Hagopian, K.F. Johnson, R. Khurana, T.
Kolberg, G. Martinez, T. Perry, H. Prosper, C. Schiber, R. Yohay, J. Zhang
Florida Institute of Technology, Melbourne, USA
M.M. Baarmand, V. Bhopatkar, S. Butalla, M. Hohlmann, D. Noonan, M. Rahmani,
M. Saunders, 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, C.
Mills, T. Roy, M.B. Tonjes, N. Varelas, H. Wang, X. Wang, Z. Wu The University
of Iowa, Iowa City, USA
M. Alhusseini, B. Bilki51, W. Clarida, K. Dilsiz69, S. Durgut, R.P.
Gandrajula, M. Haytmyradov, V. Khristenko, O.K. Köseyan, J.-P. Merlo, A.
Mestvirishvili70, 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, M. Swartz, M. Xiao The University of
Kansas, Lawrence, USA
C. Baldenegro Barrera, P. Baringer, A. Bean, S. Boren, J. Bowen, A. Bylinkin,
T. Isidori, S. Khalil, J. King, A. Kropivnitskaya, C. Lindsey, D. Majumder, W.
Mcbrayer, N. Minafra, M. Murray, C. Rogan, C. Royon, S. Sanders, E. Schmitz,
J.D. Tapia Takaki, Q. Wang, J. Williams 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, 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, A. Baty, R. Bi, S. Brandt, W. Busza, I.A. Cali, M.
D’Alfonso, G. Gomez Ceballos, M. Goncharov, P. Harris, D. Hsu, M. Hu, 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, D. Rankin, 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, S. Guts,
P. Hansen, J. Hiltbrand, Sh. Jain, S. Kalafut, Y. Kubota, Z. Lesko, J. Mans,
R. Rusack, M.A. Wadud University of Mississippi, Oxford, USA
J.G. Acosta, S. Oliveros University of Nebraska-Lincoln, Lincoln, USA
K. Bloom, D.R. Claes, C. Fangmeier, L. Finco, F. Golf, R. Gonzalez Suarez, R.
Kamalieddin, I. Kravchenko, J.E. Siado, G.R. Snow, B. Stieger State University
of New York at Buffalo, Buffalo, USA
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, G. Madigan,
D.M. Morse, T. Orimoto, L. Skinnari, A. Tishelman-Charny, T. Wamorkar, B.
Wang, A. Wisecarver, D. Wood Northwestern University, Evanston, USA
S. Bhattacharya, J. Bueghly, 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, R. Goldouzian, M. Hildreth, K. Hurtado Anampa, C. Jessop,
D.J. Karmgard, K. Lannon, W. Li, N. Loukas, N. Marinelli, I. Mcalister, F.
Meng, C. Mueller, Y. Musienko37, M. Planer, R. Ruchti, P. Siddireddy, G.
Smith, S. Taroni, M. Wayne, A. Wightman, M. Wolf, A. Woodard The Ohio State
University, Columbus, USA
J. Alimena, B. Bylsma, L.S. Durkin, S. Flowers, B. Francis, C. Hill, W. Ji, A.
Lefeld, T.Y. Ling, B.L. Winer Princeton University, Princeton, USA
S. Cooperstein, G. Dezoort, 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, Z. Wang 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, G. Negro, 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
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, A.G. Stahl Leiton, Z. Tu, A.
Zhang University of Rochester, Rochester, USA
A. Bodek, P. de Barbaro, R. Demina, Y.t. Duh, J.L. Dulemba, C. Fallon, M.
Galanti, A. Garcia-Bellido, J. Han, O. Hindrichs, A. Khukhunaishvili, E.
Ranken, P. Tan, R. Taus The Rockefeller University, New York, USA
R. Ciesielski Rutgers, The State University of New Jersey, Piscataway, USA
B. Chiarito, J.P. Chou, A. Gandrakota, Y. Gershtein, E. Halkiadakis, A. Hart,
M. Heindl, E. Hughes, S. Kaplan, 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
H. Acharya, 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, S. Kunori, K. Lamichhane, S.W. Lee, T.
Mengke, S. Muthumuni, T. Peltola, S. Undleeb, I. Volobouev, Z. Wang, A.
Whitbeck Vanderbilt University, Nashville, USA
S. Greene, A. Gurrola, R. Janjam, W. Johns, C. Maguire, A. Melo, H. Ni, K.
Padeken, F. Romeo, P. Sheldon, S. Tuo, J. Velkovska, M. Verweij University of
Virginia, Charlottesville, USA
M.W. Arenton, P. Barria, B. Cox, G. Cummings, R. Hirosky, M. Joyce, A.
Ledovskoy, C. Neu, B. Tannenwald, 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.
Gomber75, M. Herndon, A. Hervé, U. Hussain, P. Klabbers, A. Lanaro, A.
Loeliger, K. Long, R. Loveless, J. Madhusudanan Sreekala, T. Ruggles, A.
Savin, V. Sharma, W.H. Smith, D. Teague, S. Trembath-reichert, 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 UFMS, Nova Andradina, Brazil
6: Also at Universidade Federal de Pelotas, Pelotas, Brazil
7: Also at Université Libre de Bruxelles, Bruxelles, Belgium
8: Also at University of Chinese Academy of Sciences, Beijing, China
9: Also at Institute for Theoretical and Experimental Physics named by A.I.
Alikhanov of NRC ‘Kurchatov Institute’, Moscow, Russia
10: Also at Joint Institute for Nuclear Research, Dubna, Russia
11: Also at Fayoum University, El-Fayoum, Egypt
12: Now at British University in Egypt, Cairo, Egypt
13: Also at Purdue University, West Lafayette, USA
14: Also at Université de Haute Alsace, Mulhouse, France
15: Also at Tbilisi State University, Tbilisi, Georgia
16: Also at Erzincan Binali Yildirim University, Erzincan, Turkey
17: Also at CERN, European Organization for Nuclear Research, Geneva,
Switzerland
18: Also at RWTH Aachen University, III. Physikalisches Institut A, Aachen,
Germany
19: Also at University of Hamburg, Hamburg, Germany
20: Also at Brandenburg University of Technology, Cottbus, Germany
21: Also at Institute of Physics, University of Debrecen, Debrecen, Hungary,
Debrecen, Hungary
22: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary
23: Also at MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös
Loránd University, Budapest, Hungary, Budapest, Hungary
24: Also at IIT Bhubaneswar, Bhubaneswar, India, Bhubaneswar, India
25: Also at Institute of Physics, Bhubaneswar, India
26: Also at Shoolini University, Solan, India
27: Also at University of Visva-Bharati, Santiniketan, India
28: Also at Isfahan University of Technology, Isfahan, Iran
29: Also at Italian National Agency for New Technologies, Energy and
Sustainable Economic Development, Bologna, Italy
30: Also at Centro Siciliano di Fisica Nucleare e di Struttura Della Materia,
Catania, Italy
31: Also at Università degli Studi di Siena, Siena, Italy
32: Also at Scuola Normale e Sezione dell’INFN, Pisa, Italy
33: Also at Riga Technical University, Riga, Latvia, Riga, Latvia
34: Also at Malaysian Nuclear Agency, MOSTI, Kajang, Malaysia
35: Also at Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
36: Also at Warsaw University of Technology, Institute of Electronic Systems,
Warsaw, Poland
37: Also at Institute for Nuclear Research, Moscow, Russia
38: Now at National Research Nuclear University ’Moscow Engineering Physics
Institute’ (MEPhI), Moscow, Russia
39: Also at St. Petersburg State Polytechnical University, St. Petersburg,
Russia
40: Also at University of Florida, Gainesville, USA
41: Also at Imperial College, London, United Kingdom
42: Also at P.N. Lebedev Physical Institute, Moscow, Russia
43: Also at Budker Institute of Nuclear Physics, Novosibirsk, Russia
44: Also at Faculty of Physics, University of Belgrade, Belgrade, Serbia
45: Also at INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy,
Pavia, Italy
46: Also at National and Kapodistrian University of Athens, Athens, Greece
47: Also at Universität Zürich, Zurich, Switzerland
48: Also at Stefan Meyer Institute for Subatomic Physics, Vienna, Austria,
Vienna, Austria
49: Also at Gaziosmanpasa University, Tokat, Turkey
50: Also at Şırnak University, Sirnak, Turkey
51: Also at Beykent University, Istanbul, Turkey, Istanbul, Turkey
52: Also at Istanbul Aydin University, Application and Research Center for
Advanced Studies (App. & Res. Cent. for Advanced Studies), Istanbul, Turkey
53: Also at Mersin University, Mersin, Turkey
54: Also at Piri Reis University, Istanbul, Turkey
55: Also at Adiyaman University, Adiyaman, Turkey
56: Also at Ozyegin University, Istanbul, Turkey
57: Also at Izmir Institute of Technology, Izmir, Turkey
58: Also at Marmara University, Istanbul, Turkey
59: Also at Kafkas University, Kars, Turkey
60: Also at Istanbul University, Istanbul, Turkey
61: Also at Istanbul Bilgi University, Istanbul, Turkey
62: Also at Hacettepe University, Ankara, Turkey
63: Also at School of Physics and Astronomy, University of Southampton,
Southampton, United Kingdom
64: Also at IPPP Durham University, Durham, United Kingdom
65: Also at Monash University, Faculty of Science, Clayton, Australia
66: Also at Bethel University, St. Paul, Minneapolis, USA, St. Paul, USA
67: Also at Karamanoğlu Mehmetbey University, Karaman, Turkey
68: Also at Vilnius University, Vilnius, Lithuania
69: Also at Bingol University, Bingol, Turkey
70: Also at Georgian Technical University, Tbilisi, Georgia
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, Daegu, Korea
75: Also at University of Hyderabad, Hyderabad, India