J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Published for SISSA by Springer

Received: June 30, 2012

Accepted: July 24, 2012

Published: August 3, 2012

Search for stopped long-lived particles produced in pp

collisions at
√
s = 7TeV

The CMS collaboration

Abstract: A search has been performed for long-lived particles that have stopped in the

CMS detector, during 7 TeV proton-proton operations of the CERN LHC. The existence of

such particles could be inferred from observation of their decays when there were no proton-

proton collisions in the CMS detector, namely during gaps between LHC beam crossings.

Using a data set in which CMS recorded an integrated luminosity of 4.0 fb−1, and a search

interval corresponding to 246 hours of trigger live time, 12 events are observed, with a mean

background prediction of 8.6 ± 2.4 events. Limits are presented at 95% confidence level

on long-lived gluino and stop production, over 13 orders of magnitude of particle lifetime.

Assuming the “cloud model” of R-hadron interactions, a gluino with mass below 640 GeV

and a stop with mass below 340 GeV are excluded, for lifetimes between 10µs and 1000 s.

Keywords: Hadron-Hadron Scattering

Open Access, Copyright CERN,

for the benefit of the CMS collaboration

doi:10.1007/JHEP08(2012)026

http://dx.doi.org/10.1007/JHEP08(2012)026


J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Contents

1 Introduction 1

2 The CMS detector 2

3 Signal simulation 3

4 Event selection 4

5 Backgrounds 7

6 Systematic uncertainty 7

7 Search results 8

8 Excluded region in the mg̃ - mχ̃0 plane 10

9 Summary 11

The CMS collaboration 15

1 Introduction

Heavy long-lived particles are predicted by many extensions of the standard model, includ-

ing supersymmetric models [1–3], “hidden valley” scenarios [4], grand-unified theories [5]

and split supersymmetry models [6]. In models in which their production proceeds via the

strong interaction, relatively large cross sections at the Large Hadron Collider (LHC) are

predicted [7–10]. While there are astrophysical constraints on the lifetime of such parti-

cles [11], these are imprecise owing to uncertainty about their interactions. In this article,

we look for evidence of long-lived particles that stop in the Compact Muon Solenoid (CMS)

detector and decay in the quiescent periods between LHC beam crossings. Previous collider

searches have used this method to set limits on the gluino (g̃) lifetime and mass [12–15].

We now expand the search to include scalar top quarks, known as stops (̃t).

If long-lived gluinos or stops are produced at the LHC, they are expected to hadronize

into g̃g, g̃qq, g̃qqq, t̃q, t̃qq states called “R-hadrons” [16–18]. These R-hadrons lose energy

via nuclear interactions and, if charged, via ionisation, as they traverse the CMS detec-

tor. The R-hadrons that are produced with sufficiently low velocity will come to rest in

the detector volume [19], preferentially in the densest detector elements, the calorimeters.

These stopped particles may subsequently decay, which may result in an energy deposit in

the CMS calorimeters similar to that produced by a jet. If these decays occur out-of-time

with respect to the proton-proton collisions producing the parent particles, the observation

– 1 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

of such asynchronous events would constitute unambiguous evidence of new physics. This

search is complementary to analyses [20–22] in which the long-lived particle signature is

based on energy loss measurements in the charged-particle tracking system and timing in-

formation. Because this analysis relies only on calorimetry, it is sensitive to non-relativistic

particles with velocity β ≤ 0.3, for which searches based on tracking information have neg-

ligible acceptance. The use of calorimetry also provides sensitivity to R-hadrons even in

enhanced “charged-flipping” scenarios [23], where the R-hadron becomes neutral and track

reconstruction may be difficult or impossible. Finally, the stopped particle method would

allow an experimental measurement of the particle lifetime and other properties [24].

Section 2 provides an overview of the CMS experimental apparatus and the data sets

used for the analysis. In section 3 we describe the dedicated simulation procedure for the

signal, and in section 4, the online and offline event selection. The background estimation

methods are described in section 5. The systematic uncertainties are listed in section 6

and the results are given in section 7. Finally, in section 8, we interpret the results as an

excluded region in the mg̃ - mχ̃0 plane.

2 The CMS detector

The central feature of the CMS apparatus is a superconducting solenoid, of 6 m inter-

nal diameter, providing a magnetic field of 3.8 T. Within the field volume are a silicon

pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter (ECAL), and

a brass/scintillator hadron calorimeter (HCAL). Hybrid photodiodes (HPDs) are used for

light collection from the HCAL scintillators. Muons are measured in gas-ionisation de-

tectors embedded in the steel return yoke; drift tubes (DT) and resistive plate chambers

(RPC) provide coverage in the barrel, while cathode strip chambers (CSC) and RPC pro-

vide coverage in the endcaps. Extensive forward calorimetry complements the coverage

provided by the barrel and endcap detectors. CMS uses a right-handed coordinate system,

with the origin at the nominal interaction point, the x axis pointing to the centre of the

LHC, the y axis pointing up (perpendicular to the LHC plane), and the z axis along the

anticlockwise-beam direction. The polar angle, θ, is measured from the positive z axis and

the azimuthal angle, φ, is measured in the x-y plane. The pseudorapidity, η, is defined as

η = − ln[tan(θ/2)]. In the region |η| < 1.74, the HCAL cells have widths of 0.087 in η and

0.087 in φ. In the η-φ plane, and for |η| < 1.48, the HCAL cells map onto 5 × 5 ECAL

crystals arrays to form calorimeter towers projecting radially outwards from close to the

nominal interaction point. At larger values of |η|, the size of the towers increases and the

matching ECAL arrays contain fewer crystals. Within each tower, the energy deposits in

ECAL and HCAL cells are summed to define the calorimeter tower energies, subsequently

used to provide the energies and directions of hadronic jets. For this search, jets are recon-

structed offline from the energy deposits in the calorimeter towers, clustered by an iterative

cone algorithm [25] with a cone radius of 0.5 in (η, φ) space. Muons, which are used to

reject cosmic ray backgrounds, are measured in the pseudorapidity range |η| < 2.4. A more

detailed description of the CMS apparatus can be found in ref. [26].

– 2 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

The search is performed using data recorded in 2011 during regular periods of LHC

colliding beams (fills). Several fills taken towards the end of 2011 were not included in

the search because the LHC vacuum was relatively low during these periods, which may

have resulted in beam-gas backgrounds to which the search would have been sensitive.

During the period analysed, CMS recorded an integrated luminosity of 4.0 fb−1, although

it should be noted that the integrated luminosity to which this search is sensitive depends

on the particle lifetime. Since we search for stopped particle decays in the gaps between

colliding bunches, the fraction of time available for the search depends on the number (and

spacing) of proton bunches in the LHC. For the fills analysed, the number of bunches per

beam varied from 228 to 1380. During event selection, we veto any event within two 25 ns

LHC clock cycles (BX) of a bunch passing through CMS. In addition, physics triggers are

inhibited for a short time at the end of the LHC revolution period (the “LHC orbit”), while

calibration triggers are taken. After accounting for these periods, between 85%, for 228

bunch fills, and 16%, for 1380 bunch fills, of the LHC orbit is available for the search. The

total time during which the analysis is sensitive to decays of stopped particles (the “live

time”) is 246 hours. For measurement of the background due to instrumental noise, we use

a control sample taken between March and August 2010, comprising 249 hours of total live

time. The integrated luminosity delivered in the control sample (3.6 pb−1) is sufficiently

small that signal contamination can be neglected.

3 Signal simulation

The same factorized simulation is employed as in our previous publication [13]. In the first

phase, qq → g̃g̃, gg → g̃g̃, qq → t̃̃t, and gg → t̃̃t events are generated at
√
s = 7 TeV

using pythia [27] to simulate particle pair production, together with their subsequent

hadronisation into R-hadrons [28]. In this phase the gluino or stop is defined to be stable.

We simulate gluino masses in the range mg̃ = 300–1200 GeV, and stop masses in the range

mt̃ = 300–800 GeV. A modified Geant4 simulation [29] that implements a phase-space

driven “cloud model” of strong R-hadron interactions with matter [30, 31], referred to as

the “generic” model in ref. [14], is used to simulate the interaction of these R-hadrons with

the CMS detector and to record the final locations of those R-hadrons that stop in the

detector. As shown in figure 1, the probability of at least one R-hadron to stop in the CMS

detector was determined to be in the range 0.05–0.07, for both gluinos and stops in the

mass range studied.

In the next phase, we simulate the decay of the stopped R-hadron. Implicit in our

factorized approach is the assumption that the decay time is much greater than the time

required to stop the R-hadron. We again use pythia, this time to produce a R-hadron at

rest; we then translate from the nominal vertex position to the recorded stopping location

and decay the constituent gluino or stop instantaneously. We assume a 100% branching

fraction for g̃→ g χ̃0
1, which dominates in split supersymmetry for the range of gluino mass

to which the search is sensitive [32], although it should be noted that our method is also

sensitive to final states with additional jets such as g̃→ qqχ̃0
1. Similarly, we assume a 100%

branching fraction for t̃ → t χ̃0
1. The kinematics of the R-hadron decay is dominated by

– 3 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

m [GeV]
300 400 500 600 700 800 900 1000 1100 1200

st
op

ε

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

 = 7 TeVsCMS Simulation,  

g~ g~gluinos, 

t
~
 t

~
stops, 

Figure 1. Probability for one of a pair of produced long-lived particles to stop in the barrel

calorimeter (ECAL or HCAL), as a function of the particle mass.

the properties of the gluino or stop, and neutralino, as the spectator quarks do not play

a significant role. These spectator quarks cannot be ignored, however, as they participate

in the hadronisation of the gluon or quarks produced in the decay. We developed and

implemented a custom decay table to correctly account for the colour flow in these decays.

Finally, we use a specialised Monte Carlo simulation that uses the measured delivered

luminosity profile and the LHC filling scheme to simulate the time profile of stopping

particle production. By randomly generating decay times according to the exponential

distribution expected for a given lifetime hypothesis, and using the record of good data-

taking periods and the LHC filling scheme, the simulation program calculates the fraction

of stopped particle decays that occur during a triggerable interval, and hence determines

an effective luminosity for each lifetime hypothesis.

4 Event selection

In order to record decays of particles during gaps between the proton bunches that comprise

the LHC beam, we use an updated version of the dedicated calorimeter trigger employed

in our previous search [13]. This trigger uses information from the two beam position and

timing (BPTX) monitors that are positioned 175 m from the centre of CMS, along the

beam axis on each side, and that produce a signal when an LHC proton bunch passes.

We require a jet trigger together with the condition that both BPTX signals are below

threshold, ensuring that the trigger will not select particles from pp collisions or from

beam-gas interactions of protons in unpaired bunches. We also require that at most one

BPTX produces a signal in a window ±1 BX around the triggered event. This reduces

the trigger rate due to lower intensity, out of time, “satellite” bunches that accompany

– 4 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

the colliding protons. The energy deposition in the calorimeter of a jet from the R-hadron

decay is sufficiently similar to those of jets originating directly from pp collisions that a

calorimeter jet trigger can be used. At the hardware trigger level (L1), the jet transverse

energy, ET , which is calculated assuming the jet was produced at the nominal interaction

point, is required to be greater than 32 GeV, while in the software trigger (HLT) the jet

energy is required to be greater than 50 GeV. At both L1 and HLT the pseudorapidity of

the jet, |ηjet|, is required to be less than 3.0. Finally, the trigger vetoes any event that is

accompanied by a L1 endcap muon beam-halo trigger, again within a ±1 BX window.

The offline event selection, described below, is designed to reject backgrounds related

to the passage of beam through CMS, as well as backgrounds from cosmic rays and from

instrumental noise, while retaining good signal efficiency. We describe in turn the selection

criteria that reject each source of background.

Beam related backgrounds include out-of-time pp collisions, beam-gas interactions

from unpaired proton bunches, and beam-halo. In order to reject events related to an

unpaired bunch passing through CMS, events in which either BPTX is over threshold

are vetoed, in a ±2 BX window around the trigger. This criterion also rejects other beam

backgrounds, such as beam halo, and mis-timed jet triggers from in-time pp collisions. The

most significant remaining beam-related background arises from beam halo. Beam-halo

muons that result in energy deposits in the HCAL are well-reconstructed as track segments

in the muon endcap CSC system, so we reject any event containing a CSC segment. Finally,

to ensure that no out-of-time pp collision events due to satellite bunches contaminate the

search sample, events with one or more reconstructed primary vertices are rejected.

A small fraction of cosmic rays traversing CMS deposit significant energy in the

calorimeters. To remove such background, we veto events which contain one or more

reconstructed muons. Because of inefficiencies in the track reconstruction of cosmic rays,

we also veto events which contain more than two DT segments, or more than two RPC

hits. In the muon endcap, we require the hits in each RPC hit pair to be separated by

∆φ < 0.4, and in the muon barrel by ∆z < 40 cm.

In addition to beam-related backgrounds and cosmic rays, instrumental noise can also

mimic our signal. To combat this background, standard calorimeter cleaning and noise

rejection criteria [33] are applied. We restrict our search to jets in the less noisy central

HCAL, requiring that the most energetic jet in the event has |ηjet| < 1. This requirement

has been tightened from the value used in ref. [13] in order to improve the rejection of

beam-halo events, which tend to include calorimeter deposits at large pseudorapidity. A

jet with reconstructed energy above 70 GeV is required, above the trigger efficiency turn-

on region. To remove events due to noise in a single HCAL channel, events with more

than 90% of the energy deposited in three or fewer calorimeter towers are vetoed. We also

require that the leading jet has at least 60% of its energy contained in fewer than 6 towers.

To suppress noise from HPD discharges [33], events with 5 or more of the leading towers

at the same azimuthal angle, or with more than 95% of the jet energy contained within

towers at the same azimuthal angle, are rejected.

The HCAL electronics have a well-defined time response to charge deposits generated

by showering particles. Analog signal pulses produced by these electronics are sampled

– 5 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

) [GeV]
top

(EgluonE
50 100 150 200 250 300

de
t

ε

0

0.1

0.2

0.3

0.4

0.5

 = 7 TeVsCMS Simulation,  
 = 300 GeVg~m
 = 600 GeVg~m
 = 300 GeV

t
~m
 = 400 GeV

t
~m
 = 500 GeV

t
~m
 = 600 GeV

t
~m

Figure 2. Combined trigger and reconstruction efficiency (detection efficiency) for decays of parti-

cles which have stopped in the CMS barrel calorimeters, as a function of the daughter gluon energy,

Egluon, for gluino decays, and as a function of the daughter top energy, Etop, for stop decays. Each

point corresponds to fixed mg̃ or mt̃ and mχ̃0
1
. Gluino and stop masses are shown on the plot, while

the neutralino masses range from 100–548 GeV for gluino and from 50–300 GeV for stop.

at 40 MHz, synchronised with the LHC clock. These pulses are read out over ten BX

samples grouped about the pulse maximum. A pulse resulting from real energy deposition

in the calorimeters (“a physical pulse”) has some notable properties, which we use to

distinguish it from noise pulses. Physical pulses have a clear peak containing a large

fraction of the energy (Epeak), significant energy in one bunch crossing before the peak

(Epeak−1), and an exponential decay for several BX following the peak. Noise pulses tend

to be spread over many BX or localised in one BX. We use the ratios R1 = Epeak+1/Epeak

and R2 = Epeak+2/Epeak+1 to characterise the exponential decay, requiring R1 > 0.15 and

0.1 < R2 < 0.8. We also require the ratio of the peak energy to the total energy to be

between 0.3 and 0.7. Finally, we remove events with more than 30% of the energy of the

pulse outside the central four BX. The noise rejection selection was optimised to maximise

the signal to background ratio, using simulated signal and the 2010 control sample, after

removal of the cosmic ray background.

After all selection criteria have been applied, the remaining event rate measured in

the 2010 control sample is (5.6 ± 2.5) × 10−6 Hz. The efficiency for detection of a gluino

decay signal (with mg̃ = 600 GeV and mχ̃0
1

= 490 GeV), estimated from the simulation as

described above, is (51±4)% of all gluinos stopping in HCAL or ECAL barrel calorimeters.

Since we consider a two body decay mode of the gluino, with fixed energy of the daughter

gluon, a scan of gluino and neutralino masses allows us to calculate the detection efficiency

as a function of Egluon, as shown in figure 2. The efficiency is roughly constant provided the

gluon energy is above a minimum value, Emin
gluon = 100 GeV. For stop decays, the detection

– 6 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Cosmic rays Beam-halo Noise Total

5.71± 0.62 1.50± 0.70 1.4± 2.2 8.6± 2.4

Table 1. Estimated number of background events during the search period for each background

source.

efficiency is lower than the gluino, due to undetectable muons and neutrinos in the final

state, but is again roughly constant, at (31± 2)%, provided the daughter top quark energy

is greater than Emin
top = 125 GeV.

5 Backgrounds

The residual backgrounds to this search consist of instrumental noise, unidentified cosmic

rays, and unidentified beam backgrounds, principally beam halo. The cosmic ray muon re-

jection inefficiency is essentially a geometric factor, which we estimate from the cosmic ray

Monte Carlo simulation to be (0.214± 0.023)%. Taking the product of this factor with the

number of events passing the full selection criteria, apart from the cosmic ray veto, we esti-

mate the cosmic ray background to the search to be 5.71± 0.62 events. The beam-halo re-

jection inefficiency is estimated to be approximately 0.2%, using a “tag and probe” method,

where the tag is a well identified halo track in one endcap, and the probe is a CSC segment

in the other. The halo background is estimated in bins of jet pseudorapidity, from the prod-

uct of the rejection inefficiency and the number of positively identified halo events that pass

the remaining selection criteria. The resulting total halo background estimate is 1.50±0.70

events. The noise background rate is assumed to be constant over time, and is calculated

from the 2010 control sample. In this sample we observe 5 events, of which 3.56± 0.39 are

expected to be cosmic rays, giving a noise rate of (1.5±2.5)×10−6 Hz. The noise background

to the search is therefore estimated to be 1.4 ± 2.2 events. The total background to the

search is taken as the sum of cosmic ray, halo, and noise backgrounds, giving 8.6±2.4 events.

6 Systematic uncertainty

A model-independent search for stopped particles avoids many systematic uncertainties

common in collider physics, such as those due to parton density functions. However, some

sources of systematic uncertainty remain. We assign an uncertainty on the background

estimate of 28%, dominated by the statistical uncertainties in the 2010 control sample used

to estimate the noise background, and the sample used to estimate beam-halo background.

There is a small systematic uncertainty due to the jet energy scale (JES). For a JES

uncertainty of ±10%, we estimate a 7% effect on the cross section limit. The systematic

uncertainty due to trigger efficiency is negligible since the data analysed are well above

the turn-on region. Similarly, the systematic uncertainty due to reconstruction efficiency is

negligible since we restrict our search to Egluon > 100 GeV, for gluino, and Etop > 125 GeV,

for stop. Finally, there is a 2.2% uncertainty in the integrated luminosity [34].

– 7 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

τ Leff ( pb−1) Live time (s) Nexp Nobs

75 ns 19.6 2.06× 104 0.200± 0.056 1

100 ns 57.8 6.17× 104 0.60± 0.17 2

1µs 508 4.41× 105 4.3± 1.2 7

10µs 913 8.67× 105 8.5± 2.4 12

100µs 935 8.86× 105 8.6± 2.4 12

103 s 866 8.86× 105 8.6± 2.4 12

104 s 636 8.86× 105 8.6± 2.4 12

105 s 332 8.86× 105 8.6± 2.4 12

106 s 198 8.86× 105 8.6± 2.4 12

Table 2. Results of counting experiments for a range of stopped particle lifetimes, τ . The effective

luminosity, Leff, for each lifetime is shown, along with the total live time, the expected number of

background events, Nexp, and the total number of observed events, Nobs.

Setting limits on a particular model (e.g. gluinos in split supersymmetry) introduces

more substantial systematic uncertainties, since the signal yield is sensitive to the stopping

probability. The Geant4 simulation used to derive the stopping efficiency described above

implements models for both electromagnetic (EM) and nuclear interaction (NI) energy-loss

mechanisms. Whereas the EM model is well understood, the R-hadron cloud model used

for the NI has never been tested and is based on postulated physics extrapolated from low-

energy QCD. Moreover, there are alternative models [35] in which R-hadrons preferentially

become neutral after a NI. We do not attempt to quantify these uncertainties; instead we

present limits for a particular model.

7 Search results

After the selection criteria described in the preceding sections are applied, we perform

a counting experiment. The method is unchanged from that described in ref. [13]. We

consider particle lifetime hypotheses from 75 ns to 106 seconds. For lifetime hypotheses

shorter than one LHC orbit (89µs), we search within a time window following each collision,

of duration 1.3 × τ , for optimal sensitivity to the assumed lifetime τ . For longer lifetime

hypotheses, no search window is used, other than the 2 BX veto around each collision

applied during event selection, which affects all lifetime hypotheses.

For each lifetime hypothesis, the background is assumed to be flat in time, and is

calculated from the total live time in which we search, after the time window and the

2 BX veto around collisions have been applied. An effective integrated luminosity, Leff, is

calculated for each lifetime, using the Monte Carlo simulation described in section 3. The

effective luminosity decreases for very short and very long lifetimes, reflecting the fraction

of signal that occurs during the search period. The efficiency for very short lifetimes is

reduced by the ±2 BX veto around collisions, and the efficiency for very long lifetimes falls

as more signal would appear after the search period is over.

These results of the counting experiment are presented in table 2. In the search sample,

– 8 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

 [s]τ
-710 -610 -510 -410 -310 -210 -110 1 10 210 310 410 510 610

   
[p

b]
  

de
t

ε × 
st

op
ε ×

 B
F

 
× σ

-310

-210

-110

1

10

CMS 2011

-1
 L dt = 4.0 fb∫
 = 7 TeVs

 > 125 GeV
top

 > 100 GeV, EgluonE

 = 400 GeV)
g~

 (mtheoryσ

 = 400 GeV)
t
~ (mtheoryσ

95% CL Limits:

Observed

σ1±Expected 

σ2±Expected 

) 
  [

pb
]  

0 χ∼
 g

→ g~
 B

F
(

×
) g~ g~  

→
(p

p 
σ

-110

1

10

210

310
) 

  [
pb

]  
0 χ∼  t

→ t~
 B

F
(

×
) t~ t~  

→
(p

p 
σ

-110

1

10

210

310

Figure 3. Expected and observed 95% CL limits on stop and gluino pair production cross section

(left-hand axes), using the cloud model of R-hadron interactions, as a function of particle lifetime.

The theoretical cross sections for 400 GeV gluino and stop production are taken from ref. [39]. Also

shown is the model-independent 95% CL limit on particle production cross-section × branching

fraction × stopping probability × detection efficiency (right-hand axis). The structure observed

between 10−7 s and 10−5 s is due to the number of observed events incrementing when crossing

boundaries between lifetime bins.

we do not observe a significant excess above expected background, Nexp for any lifetime

hypothesis. It should be noted that the search interval for a given lifetime is either wholly

contained within, or equal to, the interval used for any greater lifetime. Hence the events ob-

served for a small lifetime hypothesis are also observed for longer lifetime hypotheses. A sig-

nal would appear as an increased number of counts across all lifetime search intervals. For

lifetimes shorter than one LHC orbit, the amount of signal in each lifetime bin would allow

a measurement of the particle lifetime. For longer lifetimes, a lifetime measurement could

be achieved using dedicated runs after the LHC beams are dumped at the end of each fill.

We set 95% confidence level (CL) limits over 13 orders of magnitude in stopped particle

lifetime, using a CLs [36, 37] limit calculator implemented in RooStats [38]. These limits

are presented in figure 3 as a function of particle lifetime. The right-hand axis of figure 3

gives a model-independent limit on particle production cross section × branching fraction

× stopping probability × detection efficiency. We then use the stopping probability and

detection efficiency obtained from simulation, to place limits on the particle production

cross section, shown on the left-hand axes of figure 3 for stop and gluino, respectively. These

limits assume visible daughter energies of Egluon > 100 GeV for gluino, and Etop > 125 GeV

for stop, ensuring the detection efficiency is on the plateau shown in figure 2. The sensitivity

of the search decreases at short and long lifetimes as the effective luminosity decreases.

The structure observed between 10−7 s and 10−5 s is due to the number of observed events

incrementing across boundaries between lifetime bins.

– 9 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

 [s]τ
-710 -610 -510 -410 -310 -210 -110 1 10 210 310 410 510 610

m
 [G

eV
]  

200

300

400

500

600

700

800

900

1000

1100
CMS 2011

-1
 L dt = 4.0 fb∫
 = 7 TeVs

 > 125 GeV
top

 > 100 GeV, EgluonE

95% CL Limits:
 observedg~ 
 observedt

~
 

σ1± expected g~ 
σ2± expected g~ 

σ1± expected t
~
 

σ2± expected t
~
 

Figure 4. The 95% CL limits on gluino and stop mass as a function of particle lifetime, assuming

the cloud model of R-hadron interactions and the theoretical production cross sections given in

ref. [39]. The structure observed between 10−7 s and 10−5 s is due to the number of observed events

incrementing across boundaries between lifetime bins. The observed mass limit for the plateau

between 10−5 s and 103 s is indicated by an arrow on the vertical axis.

Figure 4 shows the limit on particle mass as a function of lifetime, for gluino and stop,

assuming theoretical production cross sections [39], as well as BF(g̃ → gχ̃0
1) = 100% and

BF(̃t → tχ̃0
1) = 100%. For lifetimes between 10µs and 1000 s, we exclude gluinos with

masses below 640 GeV and stops with masses below 340 GeV, at 95% CL.

8 Excluded region in the mg̃ - mχ̃0 plane

For lifetimes in the range 10µs to 1000 s, we interpret the results of the analysis as an

excluded region in the mg̃ - mχ̃0 plane, assuming BF(g̃→ gχ̃0
1) = 100%. These results are

presented in figure 5. The excluded region is bounded by two contours, one at constant

mg̃ and one at constant Egluon. The latter is described by mg̃ = Emin
gluon +

√
Emin

gluon
2

+m2
χ̃0 ,

where Emin
gluon is the minimum gluon energy for which the result is valid, obtained from the

start of the plateau in reconstruction efficiency shown in figure 2.

Since the signal efficiency is essentially flat above Emin
gluon, and the background falls

steeply with energy, we obtain stronger limits on the gluino production cross section and

hence on mg̃, by repeating the analysis with increased jet energy thresholds (Ethresh) of 100,

150 and 200 GeV. For each threshold, the background is estimated as described above, and

limits are placed on the gluino production cross section and the gluino mass. The results

are given in table 3, along with the value of Emin
gluon for each threshold. The excluded region

of mg̃-mχ̃0 is shown separately for each jet energy threshold in figure 5.

– 10 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Threshold (GeV) Emin
gluon (GeV) Nexp Nobs mmin

g̃ (GeV)

70 100 8.6± 2.4 12 640

100 150 3.4± 1.1 5 680

150 220 1.5± 1.0 2 720

200 300 0.83± 0.99 2 720

Table 3. Results of the analysis using a range of jet energy thresholds. The expected background,

Nexp, and the number of observed events, Nobs, are shown. The resulting lower limit on the gluino

mass (mmin
g̃ ) assumes the minimum gluon energy (Emin

gluon) given in the table, gluino lifetime in the

range 10 µs and 1000 s, and BF(g̃→ gχ̃0
1) = 100%.

 [GeV]0χ∼
m

0 100 200 300 400 500 600

   
[G

eV
]  

g~
m

0

100

200

300

400

500

600

700

800

Kinematically forbidden

CMS 2011

-1
 L dt = 4.0 fb∫
 = 7 TeVs

 > 70 GeV

thresh
E

 > 100 GeV

threshE

 > 150 GeV

threshE

 > 200 GeV
threshE

Figure 5. The region of mg̃ - mχ̃0 excluded by the analysis, valid for gluino lifetimes 10−5 s < τg̃ <

103 s, using several jet energy thresholds Ethresh.

9 Summary

New results have been presented on long-lived particles which have stopped in the CMS

detector, after being produced in 7 TeV pp collisions from the CERN Large Hadron Collider.

A search was performed for the decay of such particles, during gaps between LHC beam

crossings, using a dedicated calorimeter trigger. Using a data set in which CMS recorded

an integrated luminosity of 4.0 fb−1, and a total search interval of 246 hours, a total of 12

events were observed, against a mean background prediction of 8.6 ± 2.4 events. Limits

are set at 95% CL on long-lived particle pair production, over 13 orders of magnitude of

lifetime. For visible energy Egluon > 100 GeV, assuming BF(g̃ → gχ̃0
1) = 100%, a gluino

with lifetimes ranging from 10µs to 1000 s and mg̃ < 640 GeV is excluded. Under similar

assumptions, Etop > 125 GeV, and BF(̃t→ tχ̃0
1) = 100%, a stop with lifetimes ranging from

– 11 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

10µs to 1000 s and mt̃ < 340 GeV is excluded. By repeating the analysis with increased jet

energy thresholds, lower limits on the gluino mass are set up to 720 GeV, valid for Egluon >

150 GeV and lifetimes in the range 10µs to 1000 s. These results considerably extend

constraints obtained from previous stopped particle searches [12–14] and are consistent

with the complementary exclusions provided by the direct searches [20–22].

Acknowledgments

We congratulate our colleagues in the CERN accelerator departments for the excellent

performance of the LHC machine. We thank the technical and administrative staff at

CERN and other CMS institutes, and acknowledge support from: FMSR (Austria); FNRS

and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria);

CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia);

RPF (Cyprus); MoER, SF0690030s09 and ERDF (Estonia); Academy of Finland, MEC,

and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany);

GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI

(Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONA-

CYT, SEP, and UASLP-FAI (Mexico); MSI (New Zealand); PAEC (Pakistan); MSHE and

NSC (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan);

MON, RosAtom, RAS and RFBR (Russia); MSTD (Serbia); MICINN and CPAN (Spain);

Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey);

STFC (United Kingdom); DOE and NSF (U.S.A.). Individuals have received support from

the Marie-Curie programme and the European Research Council (European Union); the

Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Founda-

tion; 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 Council of Science and Industrial

Research, India; and the HOMING PLUS programme of Foundation for Polish Science,

cofinanced from European Union, Regional Development Fund.

Open Access. This article is distributed under the terms of the Creative Commons

Attribution License which permits any use, distribution and reproduction in any medium,

provided the original author(s) and source are credited.

References

[1] S. Dimopoulos, M. Dine, S. Raby and S.D. Thomas, Experimental signatures of low-energy

gauge mediated supersymmetry breaking, Phys. Rev. Lett. 76 (1996) 3494 [hep-ph/9601367]

[INSPIRE].

[2] H. Baer, K.-m. Cheung and J.F. Gunion, A heavy gluino as the lightest supersymmetric

particle, Phys. Rev. D 59 (1999) 075002 [hep-ph/9806361] [INSPIRE].

– 12 –

http://dx.doi.org/10.1103/PhysRevLett.76.3494
http://arxiv.org/abs/hep-ph/9601367
http://inspirehep.net/search?p=find+EPRINT+hep-ph/9601367
http://dx.doi.org/10.1103/PhysRevD.59.075002
http://arxiv.org/abs/hep-ph/9806361
http://inspirehep.net/search?p=find+EPRINT+hep-ph/9806361


J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

[3] T. Jittoh, J. Sato, T. Shimomura and M. Yamanaka, Long life stau in the minimal

supersymmetric standard model, Phys. Rev. D 73 (2006) 055009 [hep-ph/0512197]

[INSPIRE].

[4] M.J. Strassler and K.M. Zurek, Echoes of a hidden valley at hadron colliders, Phys. Lett. B

651 (2007) 374 [hep-ph/0604261] [INSPIRE].

[5] A. Arvanitaki et al., Astrophysical probes of unification, Phys. Rev. D 79 (2009) 105022

[arXiv:0812.2075] [INSPIRE].

[6] N. Arkani-Hamed and S. Dimopoulos, Supersymmetric unification without low energy

supersymmetry and signatures for fine-tuning at the LHC, JHEP 06 (2005) 073

[hep-th/0405159] [INSPIRE].

[7] S. Dawson, E. Eichten and C. Quigg, Search for supersymmetric particles in hadron-hadron

collisions, Phys. Rev. D 31 (1985) 1581 [INSPIRE].

[8] W. Beenakker, R. Hopker, M. Spira and P. Zerwas, Squark and gluino production at hadron

colliders, Nucl. Phys. B 492 (1997) 51 [hep-ph/9610490] [INSPIRE].

[9] T. Plehn, D. Rainwater and P.Z. Skands, Squark and gluino production with jets, Phys. Lett.

B 645 (2007) 217 [hep-ph/0510144] [INSPIRE].

[10] W. Beenakker et al., Soft-gluon resummation for squark and gluino hadroproduction, JHEP

12 (2009) 041 [arXiv:0909.4418] [INSPIRE].

[11] A. Arvanitaki, C. Davis, P.W. Graham, A. Pierce and J.G. Wacker, Limits on split

supersymmetry from gluino cosmology, Phys. Rev. D 72 (2005) 075011 [hep-ph/0504210]

[INSPIRE].

[12] D0 collaboration, V. Abazov et al., Search for stopped gluinos from pp̄ collisions at√
s = 1.96 TeV, Phys. Rev. Lett. 99 (2007) 131801 [arXiv:0705.0306] [INSPIRE].

[13] CMS collaboration, V. Khachatryan et al., Search for Stopped Gluinos in pp collisions at√
s = 7 TeV, Phys. Rev. Lett. 106 (2011) 011801 [arXiv:1011.5861] [INSPIRE].

[14] ATLAS collaboration, G. Aad et al., Search for decays of stopped, long-lived particles from

7 TeV pp collisions with the ATLAS detector, Eur. Phys. J. C 72 (2012) 1965

[arXiv:1201.5595] [INSPIRE].

[15] G. Farrar, R. Mackeprang, D. Milstead and J. Roberts, Limit on the mass of a long-lived or

stable gluino, JHEP 02 (2011) 018 [arXiv:1011.2964] [INSPIRE].

[16] P. Fayet, Spontaneously broken supersymmetric theories of weak, electromagnetic and strong

interactions, Phys. Lett. B 69 (1977) 489 [INSPIRE].

[17] P. Fayet, Massive gluinos, Phys. Lett. B 78 (1978) 417 [INSPIRE].

[18] G.R. Farrar and P. Fayet, Phenomenology of the production, decay and detection of new

hadronic states associated with supersymmetry, Phys. Lett. B 76 (1978) 575 [INSPIRE].

[19] A. Arvanitaki, S. Dimopoulos, A. Pierce, S. Rajendran and J.G. Wacker, Stopping gluinos,

Phys. Rev. D 76 (2007) 055007 [hep-ph/0506242] [INSPIRE].

[20] CMS collaboration, V. Khachatryan et al., Search for Heavy Stable Charged Particles in pp

collisions at
√
s = 7 TeV, JHEP 03 (2011) 024 [arXiv:1101.1645] [INSPIRE].

[21] ATLAS collaboration, G. Aad et al., Search for Heavy Long-Lived Charged Particles with

the ATLAS detector in pp collisions at
√
s = 7 TeV, Phys. Lett. B 703 (2011) 428

[arXiv:1106.4495] [INSPIRE].

– 13 –

http://dx.doi.org/10.1103/PhysRevD.73.055009
http://arxiv.org/abs/hep-ph/0512197
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0512197
http://dx.doi.org/10.1016/j.physletb.2007.06.055
http://dx.doi.org/10.1016/j.physletb.2007.06.055
http://arxiv.org/abs/hep-ph/0604261
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0604261
http://dx.doi.org/10.1103/PhysRevD.79.105022
http://arxiv.org/abs/0812.2075
http://inspirehep.net/search?p=find+EPRINT+arXiv:0812.2075
http://dx.doi.org/10.1088/1126-6708/2005/06/073
http://arxiv.org/abs/hep-th/0405159
http://inspirehep.net/search?p=find+EPRINT+hep-th/0405159
http://dx.doi.org/10.1103/PhysRevD.31.1581
http://inspirehep.net/search?p=find+J+Phys.Rev.,D31,1581
http://dx.doi.org/10.1016/S0550-3213(97)00084-9
http://arxiv.org/abs/hep-ph/9610490
http://inspirehep.net/search?p=find+EPRINT+hep-ph/9610490
http://dx.doi.org/10.1016/j.physletb.2006.12.009
http://dx.doi.org/10.1016/j.physletb.2006.12.009
http://arxiv.org/abs/hep-ph/0510144
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0510144
http://dx.doi.org/10.1088/1126-6708/2009/12/041
http://dx.doi.org/10.1088/1126-6708/2009/12/041
http://arxiv.org/abs/0909.4418
http://inspirehep.net/search?p=find+EPRINT+arXiv:0909.4418
http://dx.doi.org/10.1103/PhysRevD.72.075011
http://arxiv.org/abs/hep-ph/0504210
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0504210
http://dx.doi.org/10.1103/PhysRevLett.99.131801
http://arxiv.org/abs/0705.0306
http://inspirehep.net/search?p=find+EPRINT+arXiv:0705.0306
http://dx.doi.org/10.1103/PhysRevLett.106.011801
http://arxiv.org/abs/1011.5861
http://inspirehep.net/search?p=find+EPRINT+arXiv:1011.5861
http://dx.doi.org/10.1140/epjc/s10052-012-1965-6
http://arxiv.org/abs/1201.5595
http://inspirehep.net/search?p=find+EPRINT+arXiv:1201.5595
http://dx.doi.org/10.1007/JHEP02(2011)018
http://arxiv.org/abs/1011.2964
http://inspirehep.net/search?p=find+EPRINT+arXiv:1011.2964
http://dx.doi.org/10.1016/0370-2693(77)90852-8
http://inspirehep.net/search?p=find+J+Phys.Lett.,B69,489
http://dx.doi.org/10.1016/0370-2693(78)90474-4
http://inspirehep.net/search?p=find+J+Phys.Lett.,B78,417
http://dx.doi.org/10.1016/0370-2693(78)90858-4
http://inspirehep.net/search?p=find+J+Phys.Lett.,B76,575
http://dx.doi.org/10.1103/PhysRevD.76.055007
http://arxiv.org/abs/hep-ph/0506242
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0506242
http://dx.doi.org/10.1007/JHEP03(2011)024
http://arxiv.org/abs/1101.1645
http://inspirehep.net/search?p=find+EPRINT+arXiv:1101.1645
http://dx.doi.org/10.1016/j.physletb.2011.08.042
http://arxiv.org/abs/1106.4495
http://inspirehep.net/search?p=find+EPRINT+arXiv:1106.4495


J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

[22] CMS collaboration, S. Chatrchyan et al., Search for heavy long-lived charged particles in pp

collisions at
√
s = 7 TeV, Phys. Lett. B 713 (2012) 408 [arXiv:1205.0272] [INSPIRE].

[23] R. Mackeprang and D. Milstead, An updated description of heavy-hadron interactions in

GEANT-4, Eur. Phys. J. C 66 (2010) 493 [arXiv:0908.1868] [INSPIRE].

[24] P.W. Graham, K. Howe, S. Rajendran and D. Stolarski, New Measurements with Stopped

Particles at the LHC (2011), arXiv:1111.4176 [INSPIRE].

[25] S. Chekanov, Jet algorithms: A Minireview (2002), hep-ph/0211298 [INSPIRE].

[26] CMS collaboration, S. Chatrchyan et al., The CMS experiment at the CERN LHC, 2008

JINST 3 S08004 [INSPIRE].

[27] T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05

(2006) 026 [hep-ph/0603175] [INSPIRE].

[28] M. Fairbairn et al., Stable massive particles at colliders, Phys. Rept. 438 (2007) 1

[hep-ph/0611040] [INSPIRE].

[29] GEANT4 collaboration, S. Agostinelli et al., GEANT4: a simulation toolkit, Nucl. Instrum.

Meth. A 506 (2003) 250 [INSPIRE].

[30] A.C. Kraan, Interactions of heavy stable hadronizing particles, Eur. Phys. J. C 37 (2004) 91

[hep-ex/0404001] [INSPIRE].

[31] R. Mackeprang and A. Rizzi, Interactions of coloured heavy stable particles in matter, Eur.

Phys. J. C 50 (2007) 353 [hep-ph/0612161] [INSPIRE].

[32] P. Gambino, G. Giudice and P. Slavich, Gluino decays in split supersymmetry, Nucl. Phys. B

726 (2005) 35 [hep-ph/0506214] [INSPIRE].

[33] CMS collaboration, S. Chatrchyan et al., Identification and filtering of uncharacteristic noise

in the CMS hadron calorimeter, 2010 JINST 5 T03014 [arXiv:0911.4881] [INSPIRE].

[34] CMS collaboration, Absolute Calibration of the Luminosity Measurement at CMS: Winter

2012 Update, CMS-PAS-SMP-12-008 (2012).

[35] F. Buccella, G.R. Farrar and A. Pugliese, R-Baryon masses, Phys. Lett. B 153 (1985) 311

[INSPIRE].

[36] T. Junk, Confidence level computation for combining searches with small statistics, Nucl.

Instrum. Meth. A 434 (1999) 435 [hep-ex/9902006] [INSPIRE].

[37] ATLAS, CMS collaborations and LHC Higgs Combination Group, Procedure for the

LHC Higgs boson search combination in Summer 2011, ATL-PHYS-PUB/CMS NOTE

2011-11 (2011).

[38] L. Moneta et al., The RooStats Project, PoS(ACAT2010)057 [arXiv:1009.1003] [INSPIRE].

[39] W. Beenakker et al., Squark and gluino hadroproduction, Int. J. Mod. Phys. A 26 (2011)

2637 [arXiv:1105.1110] [INSPIRE].

– 14 –

http://dx.doi.org/10.1016/j.physletb.2012.06.023
http://arxiv.org/abs/1205.0272
http://inspirehep.net/search?p=find+EPRINT+arXiv:1205.0272
http://dx.doi.org/10.1140/epjc/s10052-010-1262-1
http://arxiv.org/abs/0908.1868
http://inspirehep.net/search?p=find+EPRINT+arXiv:0908.1868
http://arxiv.org/abs/1111.4176
http://inspirehep.net/search?p=find+EPRINT+arXiv:1111.4176
http://arxiv.org/abs/hep-ph/0211298
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0211298
http://dx.doi.org/10.1088/1748-0221/3/08/S08004
http://dx.doi.org/10.1088/1748-0221/3/08/S08004
http://inspirehep.net/search?p=find+J+JINST,3,S08004
http://dx.doi.org/10.1088/1126-6708/2006/05/026
http://dx.doi.org/10.1088/1126-6708/2006/05/026
http://arxiv.org/abs/hep-ph/0603175
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0603175
http://dx.doi.org/10.1016/j.physrep.2006.10.002
http://arxiv.org/abs/hep-ph/0611040
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0611040
http://dx.doi.org/10.1016/S0168-9002(03)01368-8
http://dx.doi.org/10.1016/S0168-9002(03)01368-8
http://inspirehep.net/search?p=find+J+Nucl.Instrum.Meth.,A506,250
http://dx.doi.org/10.1140/epjc/s2004-01946-6
http://arxiv.org/abs/hep-ex/0404001
http://inspirehep.net/search?p=find+EPRINT+hep-ex/0404001
http://dx.doi.org/10.1140/epjc/s10052-007-0252-4
http://dx.doi.org/10.1140/epjc/s10052-007-0252-4
http://arxiv.org/abs/hep-ph/0612161
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0612161
http://dx.doi.org/10.1016/j.nuclphysb.2005.08.011
http://dx.doi.org/10.1016/j.nuclphysb.2005.08.011
http://arxiv.org/abs/hep-ph/0506214
http://inspirehep.net/search?p=find+EPRINT+hep-ph/0506214
http://dx.doi.org/10.1088/1748-0221/5/03/T03014
http://arxiv.org/abs/0911.4881
http://inspirehep.net/search?p=find+EPRINT+arXiv:0911.4881
http://cdsweb.cern.ch/record/1434360
http://dx.doi.org/10.1016/0370-2693(85)90555-6
http://inspirehep.net/search?p=find+J+Phys.Lett.,B153,311
http://dx.doi.org/10.1016/S0168-9002(99)00498-2
http://dx.doi.org/10.1016/S0168-9002(99)00498-2
http://arxiv.org/abs/hep-ex/9902006
http://inspirehep.net/search?p=find+EPRINT+hep-ex/9902006
http://cdsweb.cern.ch/record/1379837
http://cdsweb.cern.ch/record/1379837
http://pos.sissa.it/cgi-bin/reader/contribution.cgi?id=PoS(ACAT2010)057
http://arxiv.org/abs/1009.1003
http://inspirehep.net/search?p=find+EPRINT+arXiv:1009.1003
http://dx.doi.org/10.1142/S0217751X11053560
http://dx.doi.org/10.1142/S0217751X11053560
http://arxiv.org/abs/1105.1110
http://inspirehep.net/search?p=find+EPRINT+arXiv:1105.1110


J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

The CMS collaboration

Yerevan Physics Institute, Yerevan, Armenia

S. Chatrchyan, V. Khachatryan, A.M. Sirunyan, A. Tumasyan

Institut für Hochenergiephysik der OeAW, Wien, Austria

W. Adam, T. Bergauer, M. Dragicevic, J. Erö, C. Fabjan1, M. Friedl, R. Frühwirth1,

V.M. Ghete, J. Hammer, N. Hörmann, J. Hrubec, M. Jeitler1, W. Kiesenhofer, V. Knünz,

M. Krammer1, D. Liko, I. Mikulec, M. Pernicka†, B. Rahbaran, C. Rohringer, H. Rohringer,

R. Schöfbeck, J. Strauss, A. Taurok, P. Wagner, W. Waltenberger, G. Walzel, E. Widl,

C.-E. Wulz1

National Centre for Particle and High Energy Physics, Minsk, Belarus

V. Mossolov, N. Shumeiko, J. Suarez Gonzalez

Universiteit Antwerpen, Antwerpen, Belgium

S. Bansal, T. Cornelis, E.A. De Wolf, X. Janssen, S. Luyckx, T. Maes, L. Mucibello,

S. Ochesanu, B. Roland, R. Rougny, M. Selvaggi, Z. Staykova, H. Van Haevermaet,

P. Van Mechelen, N. Van Remortel, A. Van Spilbeeck

Vrije Universiteit Brussel, Brussel, Belgium

F. Blekman, S. Blyweert, J. D’Hondt, R. Gonzalez Suarez, A. Kalogeropoulos, M. Maes,

A. Olbrechts, W. Van Doninck, P. Van Mulders, G.P. Van Onsem, I. Villella

Université Libre de Bruxelles, Bruxelles, Belgium

B. Clerbaux, G. De Lentdecker, V. Dero, A.P.R. Gay, T. Hreus, A. Léonard, P.E. Marage,

T. Reis, L. Thomas, C. Vander Velde, P. Vanlaer, J. Wang

Ghent University, Ghent, Belgium

V. Adler, K. Beernaert, A. Cimmino, S. Costantini, G. Garcia, M. Grunewald, B. Klein,

J. Lellouch, A. Marinov, J. Mccartin, A.A. Ocampo Rios, D. Ryckbosch, N. Strobbe,

F. Thyssen, M. Tytgat, P. Verwilligen, S. Walsh, E. Yazgan, N. Zaganidis

Université Catholique de Louvain, Louvain-la-Neuve, Belgium

S. Basegmez, G. Bruno, R. Castello, A. Caudron, L. Ceard, C. Delaere, T. du Pree,

D. Favart, L. Forthomme, A. Giammanco2, J. Hollar, V. Lemaitre, J. Liao, O. Militaru,

C. Nuttens, D. Pagano, L. Perrini, A. Pin, K. Piotrzkowski, N. Schul, J.M. Vizan Garcia

Université de Mons, Mons, Belgium

N. Beliy, T. Caebergs, E. Daubie, G.H. Hammad

Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil

G.A. Alves, M. Correa Martins Junior, D. De Jesus Damiao, T. Martins, M.E. Pol,

M.H.G. Souza

Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

W.L. Aldá Júnior, W. Carvalho, A. Custódio, E.M. Da Costa, C. De Oliveira Martins,

S. Fonseca De Souza, D. Matos Figueiredo, L. Mundim, H. Nogima, V. Oguri, W.L. Prado

Da Silva, A. Santoro, L. Soares Jorge, A. Sznajder

– 15 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Instituto de Fisica Teorica, Universidade Estadual Paulista, Sao Paulo, Brazil

C.A. Bernardes3, F.A. Dias4, T.R. Fernandez Perez Tomei, E. M. Gregores3, C. Lagana,

F. Marinho, P.G. Mercadante3, S.F. Novaes, Sandra S. Padula

Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria

V. Genchev5, P. Iaydjiev5, S. Piperov, M. Rodozov, S. Stoykova, G. Sultanov, V. Tcholakov,

R. Trayanov, M. Vutova

University of Sofia, Sofia, Bulgaria

A. Dimitrov, R. Hadjiiska, V. Kozhuharov, L. Litov, B. Pavlov, P. Petkov

Institute of High Energy Physics, Beijing, China

J.G. Bian, G.M. Chen, H.S. Chen, C.H. Jiang, D. Liang, S. Liang, X. Meng, J. Tao,

J. Wang, X. Wang, Z. Wang, H. Xiao, M. Xu, J. Zang, Z. Zhang

State Key Lab. of Nucl. Phys. and Tech., Peking University, Beijing, China

C. Asawatangtrakuldee, Y. Ban, S. Guo, Y. Guo, W. Li, S. Liu, Y. Mao, S.J. Qian, H. Teng,

S. Wang, B. Zhu, W. Zou

Universidad de Los Andes, Bogota, Colombia

C. Avila, J.P. Gomez, B. Gomez Moreno, A.F. Osorio Oliveros, J.C. Sanabria

Technical University of Split, Split, Croatia

N. Godinovic, D. Lelas, R. Plestina6, D. Polic, I. Puljak5

University of Split, Split, Croatia

Z. Antunovic, M. Kovac

Institute Rudjer Boskovic, Zagreb, Croatia

V. Brigljevic, S. Duric, K. Kadija, J. Luetic, S. Morovic

University of Cyprus, Nicosia, Cyprus

A. Attikis, M. Galanti, G. Mavromanolakis, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis

Charles University, Prague, Czech Republic

M. Finger, M. Finger Jr.

Academy of Scientific Research and Technology of the Arab Republic of Egypt,

Egyptian Network of High Energy Physics, Cairo, Egypt

Y. Assran7, S. Elgammal8, A. Ellithi Kamel9, S. Khalil8, M.A. Mahmoud10, A. Radi11,12

National Institute of Chemical Physics and Biophysics, Tallinn, Estonia

M. Kadastik, M. Müntel, M. Raidal, L. Rebane, A. Tiko

Department of Physics, University of Helsinki, Helsinki, Finland

V. Azzolini, P. Eerola, G. Fedi, M. Voutilainen

Helsinki Institute of Physics, Helsinki, Finland

J. Härkönen, A. Heikkinen, V. Karimäki, R. Kinnunen, M.J. Kortelainen, T. Lampén,

K. Lassila-Perini, S. Lehti, T. Lindén, P. Luukka, T. Mäenpää, T. Peltola, E. Tuominen,

J. Tuominiemi, E. Tuovinen, D. Ungaro, L. Wendland

– 16 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Lappeenranta University of Technology, Lappeenranta, Finland

K. Banzuzi, A. Karjalainen, A. Korpela, T. Tuuva

DSM/IRFU, CEA/Saclay, Gif-sur-Yvette, France

M. Besancon, S. Choudhury, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, F. Ferri,

S. Ganjour, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, E. Locci,

J. Malcles, L. Millischer, A. Nayak, J. Rander, A. Rosowsky, I. Shreyber, M. Titov

Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau,

France

S. Baffioni, F. Beaudette, L. Benhabib, L. Bianchini, M. Bluj13, C. Broutin, P. Busson,

C. Charlot, N. Daci, T. Dahms, L. Dobrzynski, R. Granier de Cassagnac, M. Haguenauer,

P. Miné, C. Mironov, M. Nguyen, C. Ochando, P. Paganini, D. Sabes, R. Salerno, Y. Sirois,

C. Veelken, A. Zabi

Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, Univer-

sité de Haute Alsace Mulhouse, CNRS/IN2P3, Strasbourg, France

J.-L. Agram14, J. Andrea, D. Bloch, D. Bodin, J.-M. Brom, M. Cardaci, E.C. Chabert,

C. Collard, E. Conte14, F. Drouhin14, C. Ferro, J.-C. Fontaine14, D. Gelé, U. Goerlach,

P. Juillot, A.-C. Le Bihan, P. Van Hove

Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique

des Particules (IN2P3), Villeurbanne, France

F. Fassi, D. Mercier

Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3, Institut

de Physique Nucléaire de Lyon, Villeurbanne, France

S. Beauceron, N. Beaupere, O. Bondu, G. Boudoul, J. Chasserat, R. Chierici5, D. Contardo,

P. Depasse, H. El Mamouni, J. Fay, S. Gascon, M. Gouzevitch, B. Ille, T. Kurca,

M. Lethuillier, L. Mirabito, S. Perries, V. Sordini, S. Tosi, Y. Tschudi, P. Verdier, S. Viret

Institute of High Energy Physics and Informatization, Tbilisi State University,

Tbilisi, Georgia

Z. Tsamalaidze15

RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany

G. Anagnostou, S. Beranek, M. Edelhoff, L. Feld, N. Heracleous, O. Hindrichs, R. Jussen,

K. Klein, J. Merz, A. Ostapchuk, A. Perieanu, F. Raupach, J. Sammet, S. Schael,

D. Sprenger, H. Weber, B. Wittmer, V. Zhukov16

RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany

M. Ata, J. Caudron, E. Dietz-Laursonn, D. Duchardt, M. Erdmann, R. Fischer, A. Güth,

T. Hebbeker, C. Heidemann, K. Hoepfner, D. Klingebiel, P. Kreuzer, J. Lingemann,

C. Magass, M. Merschmeyer, A. Meyer, M. Olschewski, P. Papacz, H. Pieta, H. Reithler,

S.A. Schmitz, L. Sonnenschein, J. Steggemann, D. Teyssier, M. Weber

– 17 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany

M. Bontenackels, V. Cherepanov, G. Flügge, H. Geenen, M. Geisler, W. Haj Ahmad,

F. Hoehle, B. Kargoll, T. Kress, Y. Kuessel, A. Nowack, L. Perchalla, O. Pooth,

J. Rennefeld, P. Sauerland, A. Stahl

Deutsches Elektronen-Synchrotron, Hamburg, Germany

M. Aldaya Martin, J. Behr, W. Behrenhoff, U. Behrens, M. Bergholz17, A. Bethani,

K. Borras, A. Burgmeier, A. Cakir, L. Calligaris, A. Campbell, E. Castro, F. Costanza,

D. Dammann, C. Diez Pardos, G. Eckerlin, D. Eckstein, G. Flucke, A. Geiser,

I. Glushkov, P. Gunnellini, S. Habib, J. Hauk, G. Hellwig, H. Jung, M. Kasemann,

P. Katsas, C. Kleinwort, H. Kluge, A. Knutsson, M. Krämer, D. Krücker, E. Kuznetsova,

W. Lange, W. Lohmann17, B. Lutz, R. Mankel, I. Marfin, M. Marienfeld, I.-A. Melzer-

Pellmann, A.B. Meyer, J. Mnich, A. Mussgiller, S. Naumann-Emme, J. Olzem, H. Perrey,

A. Petrukhin, D. Pitzl, A. Raspereza, P.M. Ribeiro Cipriano, C. Riedl, E. Ron, M. Rosin,

J. Salfeld-Nebgen, R. Schmidt17, T. Schoerner-Sadenius, N. Sen, A. Spiridonov, M. Stein,

R. Walsh, C. Wissing

University of Hamburg, Hamburg, Germany

C. Autermann, V. Blobel, J. Draeger, H. Enderle, J. Erfle, U. Gebbert, M. Görner,

T. Hermanns, R.S. Höing, K. Kaschube, G. Kaussen, H. Kirschenmann, R. Klanner,

J. Lange, B. Mura, F. Nowak, T. Peiffer, N. Pietsch, D. Rathjens, C. Sander, H. Schettler,

P. Schleper, E. Schlieckau, A. Schmidt, M. Schröder, T. Schum, M. Seidel, V. Sola,

H. Stadie, G. Steinbrück, J. Thomsen, L. Vanelderen

Institut für Experimentelle Kernphysik, Karlsruhe, Germany

C. Barth, J. Berger, C. Böser, T. Chwalek, W. De Boer, A. Descroix, A. Dierlamm,

M. Feindt, M. Guthoff5, C. Hackstein, F. Hartmann, T. Hauth5, M. Heinrich, H. Held,

K.H. Hoffmann, S. Honc, I. Katkov16, J.R. Komaragiri, P. Lobelle Pardo, D. Martschei,

S. Mueller, Th. Müller, M. Niegel, A. Nürnberg, O. Oberst, A. Oehler, J. Ott, G. Quast,

K. Rabbertz, F. Ratnikov, N. Ratnikova, S. Röcker, A. Scheurer, F.-P. Schilling, G. Schott,

H.J. Simonis, F.M. Stober, D. Troendle, R. Ulrich, J. Wagner-Kuhr, S. Wayand, T. Weiler,

M. Zeise

Institute of Nuclear Physics ”Demokritos”, Aghia Paraskevi, Greece

G. Daskalakis, T. Geralis, S. Kesisoglou, A. Kyriakis, D. Loukas, I. Manolakos, A. Markou,

C. Markou, C. Mavrommatis, E. Ntomari

University of Athens, Athens, Greece

L. Gouskos, T.J. Mertzimekis, A. Panagiotou, N. Saoulidou

University of Ioánnina, Ioánnina, Greece

I. Evangelou, C. Foudas5, P. Kokkas, N. Manthos, I. Papadopoulos, V. Patras

KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary

G. Bencze, C. Hajdu5, P. Hidas, D. Horvath18, F. Sikler, V. Veszpremi, G. Vesztergombi19

– 18 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Institute of Nuclear Research ATOMKI, Debrecen, Hungary

N. Beni, S. Czellar, J. Molnar, J. Palinkas, Z. Szillasi

University of Debrecen, Debrecen, Hungary

J. Karancsi, P. Raics, Z.L. Trocsanyi, B. Ujvari

Panjab University, Chandigarh, India

S.B. Beri, V. Bhatnagar, N. Dhingra, R. Gupta, M. Jindal, M. Kaur, M.Z. Mehta, N. Nishu,

L.K. Saini, A. Sharma, J. Singh

University of Delhi, Delhi, India

Ashok Kumar, Arun Kumar, S. Ahuja, A. Bhardwaj, B.C. Choudhary, S. Malhotra,

M. Naimuddin, K. Ranjan, V. Sharma, R.K. Shivpuri

Saha Institute of Nuclear Physics, Kolkata, India

S. Banerjee, S. Bhattacharya, S. Dutta, B. Gomber, Sa. Jain, Sh. Jain, R. Khurana,

S. Sarkar, M. Sharan

Bhabha Atomic Research Centre, Mumbai, India

A. Abdulsalam, R.K. Choudhury, D. Dutta, S. Kailas, V. Kumar, P. Mehta,

A.K. Mohanty5, L.M. Pant, P. Shukla

Tata Institute of Fundamental Research - EHEP, Mumbai, India

T. Aziz, S. Ganguly, M. Guchait20, M. Maity21, G. Majumder, K. Mazumdar,

G.B. Mohanty, B. Parida, K. Sudhakar, N. Wickramage

Tata Institute of Fundamental Research - HECR, Mumbai, India

S. Banerjee, S. Dugad

Institute for Research in Fundamental Sciences (IPM), Tehran, Iran

H. Arfaei, H. Bakhshiansohi22, S.M. Etesami23, A. Fahim22, M. Hashemi, H. Hesari,

A. Jafari22, M. Khakzad, M. Mohammadi Najafabadi, S. Paktinat Mehdiabadi,

B. Safarzadeh24, M. Zeinali23

INFN Sezione di Bari a, Università di Bari b, Politecnico di Bari c, Bari, Italy

M. Abbresciaa,b, L. Barbonea,b, C. Calabriaa,b,5, S.S. Chhibraa,b, A. Colaleoa,

D. Creanzaa,c, N. De Filippisa,c,5, M. De Palmaa,b, L. Fiorea, G. Iasellia,c, L. Lusitoa,b,

G. Maggia,c, M. Maggia, B. Marangellia,b, S. Mya,c, S. Nuzzoa,b, N. Pacificoa,b,

A. Pompilia,b, G. Pugliesea,c, G. Selvaggia,b, L. Silvestrisa, G. Singha,b, R. Venditti,

G. Zitoa

INFN Sezione di Bologna a, Università di Bologna b, Bologna, Italy

G. Abbiendia, A.C. Benvenutia, D. Bonacorsia,b, S. Braibant-Giacomellia,b,

L. Brigliadoria,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa, M. Cuffiania,b,

G.M. Dallavallea, F. Fabbria, A. Fanfania,b, D. Fasanellaa,b,5, P. Giacomellia,

C. Grandia, L. Guiduccia,b, S. Marcellinia, G. Masettia, M. Meneghellia,b,5, A. Montanaria,

F.L. Navarriaa,b, F. Odoricia, A. Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b,

G. Sirolia,b, R. Travaglinia,b

– 19 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

INFN Sezione di Catania a, Università di Catania b, Catania, Italy

S. Albergoa,b, G. Cappelloa,b, M. Chiorbolia,b, S. Costaa,b, R. Potenzaa,b, A. Tricomia,b,

C. Tuvea,b

INFN Sezione di Firenze a, Università di Firenze b, Firenze, Italy

G. Barbaglia, V. Ciullia,b, C. Civininia, R. D’Alessandroa,b, E. Focardia,b, S. Frosalia,b,

E. Galloa, S. Gonzia,b, M. Meschinia, S. Paolettia, G. Sguazzonia, A. Tropianoa,5

INFN Laboratori Nazionali di Frascati, Frascati, Italy

L. Benussi, S. Bianco, S. Colafranceschi25, F. Fabbri, D. Piccolo

INFN Sezione di Genova, Genova, Italy

P. Fabbricatore, R. Musenich

INFN Sezione di Milano-Bicocca a, Università di Milano-Bicocca b, Milano,

Italy

A. Benagliaa,b,5, F. De Guioa,b, L. Di Matteoa,b,5, S. Fiorendia,b, S. Gennaia,5, A. Ghezzia,b,

S. Malvezzia, R.A. Manzonia,b, A. Martellia,b, A. Massironia,b,5, D. Menascea, L. Moronia,

M. Paganonia,b, D. Pedrinia, S. Ragazzia,b, N. Redaellia, S. Salaa, T. Tabarelli de Fatisa,b

INFN Sezione di Napoli a, Università di Napoli ”Federico II” b, Napoli, Italy

S. Buontempoa, C.A. Carrillo Montoyaa,5, N. Cavalloa,26, A. De Cosaa,b,5, O. Doganguna,b,

F. Fabozzia,26, A.O.M. Iorioa, L. Listaa, S. Meolaa,27, M. Merolaa,b, P. Paoluccia,5

INFN Sezione di Padova a, Università di Padova b, Università di

Trento (Trento) c, Padova, Italy

P. Azzia, N. Bacchettaa,5, M. Bellatoa, D. Biselloa,b, A. Brancaa,5, R. Carlina,b,

P. Checchiaa, T. Dorigoa, F. Gasparinia,b, A. Gozzelinoa, K. Kanishcheva,c, S. Lacapraraa,

I. Lazzizzeraa,c, M. Margonia,b, A.T. Meneguzzoa,b, J. Pazzinia, N. Pozzobona,b,

P. Ronchesea,b, F. Simonettoa,b, E. Torassaa, M. Tosia,b,5, S. Vaninia,b, S. Venturaa,

P. Zottoa,b, A. Zucchettaa, G. Zumerlea,b

INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy

M. Gabusia,b, S.P. Rattia,b, C. Riccardia,b, P. Torrea,b, P. Vituloa,b

INFN Sezione di Perugia a, Università di Perugia b, Perugia, Italy

M. Biasinia,b, G.M. Bileia, L. Fanòa,b, P. Laricciaa,b, A. Lucaronia,b,5, G. Mantovania,b,

M. Menichellia, A. Nappia,b, F. Romeoa,b, A. Sahaa, A. Santocchiaa,b, S. Taronia,b,5

INFN Sezione di Pisa a, Università di Pisa b, Scuola Normale Superiore di

Pisa c, Pisa, Italy

P. Azzurria,c, G. Bagliesia, T. Boccalia, G. Broccoloa,c, R. Castaldia, R.T. D’Agnoloa,c,

R. Dell’Orsoa, F. Fioria,b,5, L. Foàa,c, A. Giassia, A. Kraana, F. Ligabuea,c, T. Lomtadzea,

L. Martinia,28, A. Messineoa,b, F. Pallaa, A. Rizzia,b, A.T. Serbana,29, P. Spagnoloa,

P. Squillaciotia,5, R. Tenchinia, G. Tonellia,b,5, A. Venturia,5, P.G. Verdinia

– 20 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

INFN Sezione di Roma a, Università di Roma ”La Sapienza” b, Roma, Italy

L. Baronea,b, F. Cavallaria, D. Del Rea,b,5, M. Diemoza, M. Grassia,b,5, E. Longoa,b,

P. Meridiania,5, F. Michelia,b, S. Nourbakhsha,b, G. Organtinia,b, R. Paramattia,

S. Rahatloua,b, M. Sigamania, L. Soffia,b

INFN Sezione di Torino a, Università di Torino b, Università del Piemonte

Orientale (Novara) c, Torino, Italy

N. Amapanea,b, R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c, C. Biinoa, N. Cartigliaa,

M. Costaa,b, N. Demariaa, A. Grazianoa,b, C. Mariottia,5, S. Masellia, E. Migliorea,b,

V. Monacoa,b, M. Musicha,5, M.M. Obertinoa,c, N. Pastronea, M. Pelliccionia,

A. Potenzaa,b, A. Romeroa,b, M. Ruspaa,c, R. Sacchia,b, A. Solanoa,b, A. Staianoa, A. Vilela

Pereiraa

INFN Sezione di Trieste a, Università di Trieste b, Trieste, Italy

S. Belfortea, V. Candelisea,b, F. Cossuttia, G. Della Riccaa,b, B. Gobboa, M. Maronea,b,5,

D. Montaninoa,b,5, A. Penzoa, A. Schizzia,b

Kangwon National University, Chunchon, Korea

S.G. Heo, T.Y. Kim, S.K. Nam

Kyungpook National University, Daegu, Korea

S. Chang, J. Chung, D.H. Kim, G.N. Kim, D.J. Kong, H. Park, S.R. Ro, D.C. Son, T. Son

Chonnam National University, Institute for Universe and Elementary Particles,

Kwangju, Korea

J.Y. Kim, Zero J. Kim, S. Song

Korea University, Seoul, Korea

S. Choi, D. Gyun, B. Hong, M. Jo, H. Kim, T.J. Kim, K.S. Lee, D.H. Moon, S.K. Park

University of Seoul, Seoul, Korea

M. Choi, J.H. Kim, C. Park, I.C. Park, S. Park, G. Ryu

Sungkyunkwan University, Suwon, Korea

Y. Cho, Y. Choi, Y.K. Choi, J. Goh, M.S. Kim, E. Kwon, B. Lee, J. Lee, S. Lee, H. Seo,

I. Yu

Vilnius University, Vilnius, Lithuania

M.J. Bilinskas, I. Grigelionis, M. Janulis, A. Juodagalvis

Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico

H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-de La Cruz, R. Lopez-Fernandez,

R. Magaña Villalba, J. Mart́ınez-Ortega, A. Sánchez-Hernández, L.M. Villasenor-Cendejas

Universidad Iberoamericana, Mexico City, Mexico

S. Carrillo Moreno, F. Vazquez Valencia

Benemerita Universidad Autonoma de Puebla, Puebla, Mexico

H.A. Salazar Ibarguen

– 21 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Universidad Autónoma de San Luis Potośı, San Luis Potośı, Mexico

E. Casimiro Linares, A. Morelos Pineda, M.A. Reyes-Santos

University of Auckland, Auckland, New Zealand

D. Krofcheck

University of Canterbury, Christchurch, New Zealand

A.J. Bell, P.H. Butler, R. Doesburg, S. Reucroft, H. Silverwood

National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan

M. Ahmad, M.I. Asghar, H.R. Hoorani, S. Khalid, W.A. Khan, T. Khurshid, S. Qazi,

M.A. Shah, M. Shoaib

Institute of Experimental Physics, Faculty of Physics, University of Warsaw,

Warsaw, Poland

G. Brona, K. Bunkowski, M. Cwiok, W. Dominik, K. Doroba, A. Kalinowski, M. Konecki,

J. Krolikowski

Soltan Institute for Nuclear Studies, Warsaw, Poland

H. Bialkowska, B. Boimska, T. Frueboes, R. Gokieli, M. Górski, M. Kazana, K. Nawrocki,

K. Romanowska-Rybinska, M. Szleper, G. Wrochna, P. Zalewski

Laboratório de Instrumentação e F́ısica Experimental de Part́ıculas, Lisboa,

Portugal

N. Almeida, P. Bargassa, A. David, P. Faccioli, M. Fernandes, P.G. Ferreira Parracho,

M. Gallinaro, J. Seixas, J. Varela, P. Vischia

Joint Institute for Nuclear Research, Dubna, Russia

I. Belotelov, P. Bunin, M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin,

G. Kozlov, A. Lanev, A. Malakhov, P. Moisenz, V. Palichik, V. Perelygin, S. Shmatov,

V. Smirnov, A. Volodko, A. Zarubin

Petersburg Nuclear Physics Institute, Gatchina (St Petersburg), Russia

S. Evstyukhin, V. Golovtsov, Y. Ivanov, V. Kim, P. Levchenko, V. Murzin, V. Oreshkin,

I. Smirnov, V. Sulimov, L. Uvarov, S. Vavilov, A. Vorobyev, An. Vorobyev

Institute for Nuclear Research, Moscow, Russia

Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, M. Kirsanov, N. Krasnikov,

V. Matveev, A. Pashenkov, D. Tlisov, A. Toropin

Institute for Theoretical and Experimental Physics, Moscow, Russia

V. Epshteyn, M. Erofeeva, V. Gavrilov, M. Kossov5, N. Lychkovskaya, V. Popov,

G. Safronov, S. Semenov, V. Stolin, E. Vlasov, A. Zhokin

Moscow State University, Moscow, Russia

A. Belyaev, E. Boos, M. Dubinin4, L. Dudko, A. Ershov, A. Gribushin, V. Klyukhin,

O. Kodolova, I. Lokhtin, A. Markina, S. Obraztsov, M. Perfilov, S. Petrushanko, A. Popov,

L. Sarycheva†, V. Savrin, A. Snigirev

– 22 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

P.N. Lebedev Physical Institute, Moscow, Russia

V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Leonidov, G. Mesyats,

S.V. Rusakov, A. Vinogradov

State Research Center of Russian Federation, Institute for High Energy

Physics, Protvino, Russia

I. Azhgirey, I. Bayshev, S. Bitioukov, V. Grishin5, V. Kachanov, D. Konstantinov,

A. Korablev, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, L. Tourtchanovitch, S. Troshin,

N. Tyurin, A. Uzunian, A. Volkov

University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear

Sciences, Belgrade, Serbia

P. Adzic30, M. Djordjevic, M. Ekmedzic, D. Krpic30, J. Milosevic

Centro de Investigaciones Energéticas Medioambientales

y Tecnológicas (CIEMAT), Madrid, Spain

M. Aguilar-Benitez, J. Alcaraz Maestre, P. Arce, C. Battilana, E. Calvo, M. Cerrada,

M. Chamizo Llatas, N. Colino, B. De La Cruz, A. Delgado Peris, D. Domı́nguez Vázquez,

C. Fernandez Bedoya, J.P. Fernández Ramos, A. Ferrando, J. Flix, M.C. Fouz, P. Garcia-

Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez, M.I. Josa, G. Merino, J. Puerta

Pelayo, A. Quintario Olmeda, I. Redondo, L. Romero, J. Santaolalla, M.S. Soares,

C. Willmott

Universidad Autónoma de Madrid, Madrid, Spain

C. Albajar, G. Codispoti, J.F. de Trocóniz

Universidad de Oviedo, Oviedo, Spain

H. Brun, J. Cuevas, J. Fernandez Menendez, S. Folgueras, I. Gonzalez Caballero, L. Lloret

Iglesias, J. Piedra Gomez31

Instituto de F́ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria,

Santander, Spain

J.A. Brochero Cifuentes, I.J. Cabrillo, A. Calderon, S.H. Chuang, J. Duarte Campderros,

M. Felcini32, M. Fernandez, G. Gomez, J. Gonzalez Sanchez, C. Jorda, A. Lopez Virto,

J. Marco, R. Marco, C. Martinez Rivero, F. Matorras, F.J. Munoz Sanchez, T. Rodrigo,

A.Y. Rodŕıguez-Marrero, A. Ruiz-Jimeno, L. Scodellaro, M. Sobron Sanudo, I. Vila,

R. Vilar Cortabitarte

CERN, European Organization for Nuclear Research, Geneva, Switzerland

D. Abbaneo, E. Auffray, G. Auzinger, P. Baillon, A.H. Ball, D. Barney, J.F. Benitez,

C. Bernet6, G. Bianchi, P. Bloch, A. Bocci, A. Bonato, C. Botta, H. Breuker, T. Camporesi,

G. Cerminara, T. Christiansen, J.A. Coarasa Perez, D. D’Enterria, A. Dabrowski, A. De

Roeck, S. Di Guida, M. Dobson, N. Dupont-Sagorin, A. Elliott-Peisert, B. Frisch, W. Funk,

G. Georgiou, M. Giffels, D. Gigi, K. Gill, D. Giordano, M. Giunta, F. Glege, R. Gomez-

Reino Garrido, P. Govoni, S. Gowdy, R. Guida, M. Hansen, P. Harris, C. Hartl, J. Harvey,

B. Hegner, A. Hinzmann, V. Innocente, P. Janot, K. Kaadze, E. Karavakis, K. Kousouris,

P. Lecoq, Y.-J. Lee, P. Lenzi, C. Lourenço, T. Mäki, M. Malberti, L. Malgeri, M. Mannelli,

– 23 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

L. Masetti, F. Meijers, S. Mersi, E. Meschi, R. Moser, M.U. Mozer, M. Mulders,

P. Musella, E. Nesvold, T. Orimoto, L. Orsini, E. Palencia Cortezon, E. Perez, L. Perrozzi,

A. Petrilli, A. Pfeiffer, M. Pierini, M. Pimiä, D. Piparo, G. Polese, L. Quertenmont,

A. Racz, W. Reece, J. Rodrigues Antunes, G. Rolandi33, T. Rommerskirchen, C. Rovelli34,

M. Rovere, H. Sakulin, F. Santanastasio, C. Schäfer, C. Schwick, I. Segoni, S. Sekmen,

A. Sharma, P. Siegrist, P. Silva, M. Simon, P. Sphicas35, D. Spiga, M. Spiropulu4, A. Tsirou,

G.I. Veres19, J.R. Vlimant, H.K. Wöhri, S.D. Worm36, W.D. Zeuner

Paul Scherrer Institut, Villigen, Switzerland

W. Bertl, K. Deiters, W. Erdmann, K. Gabathuler, R. Horisberger, Q. Ingram,

H.C. Kaestli, S. König, D. Kotlinski, U. Langenegger, F. Meier, D. Renker, T. Rohe,

J. Sibille37

Institute for Particle Physics, ETH Zurich, Zurich, Switzerland

L. Bäni, P. Bortignon, M.A. Buchmann, B. Casal, N. Chanon, A. Deisher, G. Dissertori,

M. Dittmar, M. Dünser, J. Eugster, K. Freudenreich, C. Grab, D. Hits, P. Lecomte,

W. Lustermann, A.C. Marini, P. Martinez Ruiz del Arbol, N. Mohr, F. Moortgat,

C. Nägeli38, P. Nef, F. Nessi-Tedaldi, F. Pandolfi, L. Pape, F. Pauss, M. Peruzzi,

F.J. Ronga, M. Rossini, L. Sala, A.K. Sanchez, A. Starodumov39, B. Stieger, M. Takahashi,

L. Tauscher†, A. Thea, K. Theofilatos, D. Treille, C. Urscheler, R. Wallny, H.A. Weber,

L. Wehrli

Universität Zürich, Zurich, Switzerland

E. Aguilo, C. Amsler, V. Chiochia, S. De Visscher, C. Favaro, M. Ivova Rikova, B. Millan

Mejias, P. Otiougova, P. Robmann, H. Snoek, S. Tupputi, M. Verzetti

National Central University, Chung-Li, Taiwan

Y.H. Chang, K.H. Chen, C.M. Kuo, S.W. Li, W. Lin, Z.K. Liu, Y.J. Lu, D. Mekterovic,

A.P. Singh, R. Volpe, S.S. Yu

National Taiwan University (NTU), Taipei, Taiwan

P. Bartalini, P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, C. Dietz,

U. Grundler, W.-S. Hou, Y. Hsiung, K.Y. Kao, Y.J. Lei, R.-S. Lu, D. Majumder,

E. Petrakou, X. Shi, J.G. Shiu, Y.M. Tzeng, X. Wan, M. Wang

Cukurova University, Adana, Turkey

A. Adiguzel, M.N. Bakirci40, S. Cerci41, C. Dozen, I. Dumanoglu, E. Eskut, S. Girgis,

G. Gokbulut, E. Gurpinar, I. Hos, E.E. Kangal, G. Karapinar42, A. Kayis Topaksu,

G. Onengut, K. Ozdemir, S. Ozturk43, A. Polatoz, K. Sogut44, D. Sunar Cerci41, B. Tali41,

H. Topakli40, L.N. Vergili, M. Vergili

Middle East Technical University, Physics Department, Ankara, Turkey

I.V. Akin, T. Aliev, B. Bilin, S. Bilmis, M. Deniz, H. Gamsizkan, A.M. Guler, K. Ocalan,

A. Ozpineci, M. Serin, R. Sever, U.E. Surat, M. Yalvac, E. Yildirim, M. Zeyrek

Bogazici University, Istanbul, Turkey

E. Gülmez, B. Isildak45, M. Kaya46, O. Kaya46, S. Ozkorucuklu47, N. Sonmez48

– 24 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Istanbul Technical University, Istanbul, Turkey

K. Cankocak

National Scientific Center, Kharkov Institute of Physics and Technology,

Kharkov, Ukraine

L. Levchuk

University of Bristol, Bristol, United Kingdom

F. Bostock, J.J. Brooke, E. Clement, D. Cussans, H. Flacher, R. Frazier, J. Goldstein,

M. Grimes, G.P. Heath, H.F. Heath, L. Kreczko, S. Metson, D.M. Newbold36,

K. Nirunpong, A. Poll, S. Senkin, V.J. Smith, T. Williams

Rutherford Appleton Laboratory, Didcot, United Kingdom

L. Basso49, K.W. Bell, A. Belyaev49, C. Brew, R.M. Brown, D.J.A. Cockerill,

J.A. Coughlan, K. Harder, S. Harper, J. Jackson, B.W. Kennedy, E. Olaiya, D. Petyt,

B.C. Radburn-Smith, C.H. Shepherd-Themistocleous, I.R. Tomalin, W.J. Womersley

Imperial College, London, United Kingdom

R. Bainbridge, G. Ball, R. Beuselinck, O. Buchmuller, D. Colling, N. Cripps, M. Cutajar,

P. Dauncey, G. Davies, M. Della Negra, W. Ferguson, J. Fulcher, D. Futyan, A. Gilbert,

A. Guneratne Bryer, G. Hall, Z. Hatherell, J. Hays, G. Iles, M. Jarvis, G. Karapostoli,

L. Lyons, A.-M. Magnan, J. Marrouche, B. Mathias, R. Nandi, J. Nash, A. Nikitenko39,

A. Papageorgiou, J. Pela5, M. Pesaresi, K. Petridis, M. Pioppi50, D.M. Raymond,

S. Rogerson, A. Rose, M.J. Ryan, C. Seez, P. Sharp†, A. Sparrow, M. Stoye, A. Tapper,

M. Vazquez Acosta, T. Virdee, S. Wakefield, N. Wardle, T. Whyntie

Brunel University, Uxbridge, United Kingdom

M. Chadwick, J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, D. Leggat, D. Leslie,

W. Martin, I.D. Reid, P. Symonds, L. Teodorescu, M. Turner

Baylor University, Waco, U.S.A.

K. Hatakeyama, H. Liu, T. Scarborough

The University of Alabama, Tuscaloosa, U.S.A.

O. Charaf, C. Henderson, P. Rumerio

Boston University, Boston, U.S.A.

A. Avetisyan, T. Bose, C. Fantasia, A. Heister, J. St. John, P. Lawson, D. Lazic, J. Rohlf,

D. Sperka, L. Sulak

Brown University, Providence, U.S.A.

J. Alimena, S. Bhattacharya, D. Cutts, A. Ferapontov, U. Heintz, S. Jabeen, G. Kukartsev,

E. Laird, G. Landsberg, M. Luk, M. Narain, D. Nguyen, M. Segala, T. Sinthuprasith,

T. Speer, K.V. Tsang

University of California, Davis, Davis, U.S.A.

R. Breedon, G. Breto, M. Calderon De La Barca Sanchez, S. Chauhan, M. Chertok,

J. Conway, R. Conway, P.T. Cox, J. Dolen, R. Erbacher, M. Gardner, R. Houtz, W. Ko,

A. Kopecky, R. Lander, T. Miceli, D. Pellett, B. Rutherford, M. Searle, J. Smith,

M. Squires, M. Tripathi, R. Vasquez Sierra

– 25 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

University of California, Los Angeles, Los Angeles, U.S.A.

V. Andreev, D. Cline, R. Cousins, J. Duris, S. Erhan, P. Everaerts, C. Farrell, J. Hauser,

M. Ignatenko, C. Jarvis, C. Plager, G. Rakness, P. Schlein†, J. Tucker, V. Valuev, M. Weber

University of California, Riverside, Riverside, U.S.A.

J. Babb, R. Clare, M.E. Dinardo, J. Ellison, J.W. Gary, F. Giordano, G. Hanson,

G.Y. Jeng51, H. Liu, O.R. Long, A. Luthra, H. Nguyen, S. Paramesvaran, J. Sturdy,

S. Sumowidagdo, R. Wilken, S. Wimpenny

University of California, San Diego, La Jolla, U.S.A.

W. Andrews, J.G. Branson, G.B. Cerati, S. Cittolin, D. Evans, F. Golf, A. Holzner,

R. Kelley, M. Lebourgeois, J. Letts, I. Macneill, B. Mangano, S. Padhi, C. Palmer,

G. Petrucciani, M. Pieri, M. Sani, V. Sharma, S. Simon, E. Sudano, M. Tadel, Y. Tu,

A. Vartak, S. Wasserbaech52, F. Würthwein, A. Yagil, J. Yoo

University of California, Santa Barbara, Santa Barbara, U.S.A.

D. Barge, R. Bellan, C. Campagnari, M. D’Alfonso, T. Danielson, K. Flowers, P. Geffert,

J. Incandela, C. Justus, P. Kalavase, S.A. Koay, D. Kovalskyi, V. Krutelyov, S. Lowette,

N. Mccoll, V. Pavlunin, F. Rebassoo, J. Ribnik, J. Richman, R. Rossin, D. Stuart, W. To,

C. West

California Institute of Technology, Pasadena, U.S.A.

A. Apresyan, A. Bornheim, Y. Chen, E. Di Marco, J. Duarte, M. Gataullin, Y. Ma, A. Mott,

H.B. Newman, C. Rogan, V. Timciuc, P. Traczyk, J. Veverka, R. Wilkinson, Y. Yang,

R.Y. Zhu

Carnegie Mellon University, Pittsburgh, U.S.A.

B. Akgun, R. Carroll, T. Ferguson, Y. Iiyama, D.W. Jang, Y.F. Liu, M. Paulini, H. Vogel,

I. Vorobiev

University of Colorado at Boulder, Boulder, U.S.A.

J.P. Cumalat, B.R. Drell, C.J. Edelmaier, W.T. Ford, A. Gaz, B. Heyburn, E. Luiggi

Lopez, J.G. Smith, K. Stenson, K.A. Ulmer, S.R. Wagner

Cornell University, Ithaca, U.S.A.

J. Alexander, A. Chatterjee, N. Eggert, L.K. Gibbons, B. Heltsley, A. Khukhunaishvili,

B. Kreis, N. Mirman, G. Nicolas Kaufman, J.R. Patterson, A. Ryd, E. Salvati, W. Sun,

W.D. Teo, J. Thom, J. Thompson, J. Vaughan, Y. Weng, L. Winstrom, P. Wittich

Fairfield University, Fairfield, U.S.A.

D. Winn

Fermi National Accelerator Laboratory, Batavia, U.S.A.

S. Abdullin, M. Albrow, J. Anderson, L.A.T. Bauerdick, A. Beretvas, J. Berryhill,

P.C. Bhat, I. Bloch, K. Burkett, J.N. Butler, V. Chetluru, H.W.K. Cheung, F. Chlebana,

V.D. Elvira, I. Fisk, J. Freeman, Y. Gao, D. Green, O. Gutsche, J. Hanlon, R.M. Harris,

J. Hirschauer, B. Hooberman, S. Jindariani, M. Johnson, U. Joshi, B. Kilminster,

– 26 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

B. Klima, S. Kunori, S. Kwan, C. Leonidopoulos, D. Lincoln, R. Lipton, J. Lykken,

K. Maeshima, J.M. Marraffino, S. Maruyama, D. Mason, P. McBride, K. Mishra,

S. Mrenna, Y. Musienko53, C. Newman-Holmes, V. O’Dell, O. Prokofyev, E. Sexton-

Kennedy, S. Sharma, W.J. Spalding, L. Spiegel, P. Tan, L. Taylor, S. Tkaczyk, N.V. Tran,

L. Uplegger, E.W. Vaandering, R. Vidal, J. Whitmore, W. Wu, F. Yang, F. Yumiceva,

J.C. Yun

University of Florida, Gainesville, U.S.A.

D. Acosta, P. Avery, D. Bourilkov, M. Chen, S. Das, M. De Gruttola, G.P. Di Giovanni,

D. Dobur, A. Drozdetskiy, R.D. Field, M. Fisher, Y. Fu, I.K. Furic, J. Gartner, J. Hugon,

B. Kim, J. Konigsberg, A. Korytov, A. Kropivnitskaya, T. Kypreos, J.F. Low, K. Matchev,

P. Milenovic54, G. Mitselmakher, L. Muniz, R. Remington, A. Rinkevicius, P. Sellers,

N. Skhirtladze, M. Snowball, J. Yelton, M. Zakaria

Florida International University, Miami, U.S.A.

V. Gaultney, L.M. Lebolo, S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez

Florida State University, Tallahassee, U.S.A.

J.R. Adams, T. Adams, A. Askew, J. Bochenek, J. Chen, B. Diamond, S.V. Gleyzer,

J. Haas, S. Hagopian, V. Hagopian, M. Jenkins, K.F. Johnson, H. Prosper,

V. Veeraraghavan, M. Weinberg

Florida Institute of Technology, Melbourne, U.S.A.

M.M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopiyanov

University of Illinois at Chicago (UIC), Chicago, U.S.A.

M.R. Adams, I.M. Anghel, L. Apanasevich, Y. Bai, V.E. Bazterra, R.R. Betts,

I. Bucinskaite, J. Callner, R. Cavanaugh, C. Dragoiu, O. Evdokimov, L. Gauthier,

C.E. Gerber, D.J. Hofman, S. Khalatyan, F. Lacroix, M. Malek, C. O’Brien, C. Silkworth,

D. Strom, N. Varelas

The University of Iowa, Iowa City, U.S.A.

U. Akgun, E.A. Albayrak, B. Bilki55, W. Clarida, F. Duru, S. Griffiths, J.-P. Merlo,

H. Mermerkaya56, A. Mestvirishvili, A. Moeller, J. Nachtman, C.R. Newsom, E. Norbeck,

Y. Onel, F. Ozok, S. Sen, E. Tiras, J. Wetzel, T. Yetkin, K. Yi

Johns Hopkins University, Baltimore, U.S.A.

B.A. Barnett, B. Blumenfeld, S. Bolognesi, D. Fehling, G. Giurgiu, A.V. Gritsan, Z.J. Guo,

G. Hu, P. Maksimovic, S. Rappoccio, M. Swartz, A. Whitbeck

The University of Kansas, Lawrence, U.S.A.

P. Baringer, A. Bean, G. Benelli, O. Grachov, R.P. Kenny Iii, M. Murray, D. Noonan,

S. Sanders, R. Stringer, G. Tinti, J.S. Wood, V. Zhukova

Kansas State University, Manhattan, U.S.A.

A.F. Barfuss, T. Bolton, I. Chakaberia, A. Ivanov, S. Khalil, M. Makouski, Y. Maravin,

S. Shrestha, I. Svintradze

– 27 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Lawrence Livermore National Laboratory, Livermore, U.S.A.

J. Gronberg, D. Lange, D. Wright

University of Maryland, College Park, U.S.A.

A. Baden, M. Boutemeur, B. Calvert, S.C. Eno, J.A. Gomez, N.J. Hadley, R.G. Kellogg,

M. Kirn, T. Kolberg, Y. Lu, M. Marionneau, A.C. Mignerey, K. Pedro, A. Peterman,

A. Skuja, J. Temple, M.B. Tonjes, S.C. Tonwar, E. Twedt

Massachusetts Institute of Technology, Cambridge, U.S.A.

G. Bauer, J. Bendavid, W. Busza, E. Butz, I.A. Cali, M. Chan, V. Dutta, G. Gomez

Ceballos, M. Goncharov, K.A. Hahn, Y. Kim, M. Klute, K. Krajczar57, W. Li, P.D. Luckey,

T. Ma, S. Nahn, C. Paus, D. Ralph, C. Roland, G. Roland, M. Rudolph, G.S.F. Stephans,

F. Stöckli, K. Sumorok, K. Sung, D. Velicanu, E.A. Wenger, R. Wolf, B. Wyslouch, S. Xie,

M. Yang, Y. Yilmaz, A.S. Yoon, M. Zanetti

University of Minnesota, Minneapolis, U.S.A.

S.I. Cooper, B. Dahmes, A. De Benedetti, G. Franzoni, A. Gude, S.C. Kao, K. Klapoetke,

Y. Kubota, J. Mans, N. Pastika, R. Rusack, M. Sasseville, A. Singovsky, N. Tambe,

J. Turkewitz

University of Mississippi, University, U.S.A.

L.M. Cremaldi, R. Kroeger, L. Perera, R. Rahmat, D.A. Sanders

University of Nebraska-Lincoln, Lincoln, U.S.A.

E. Avdeeva, K. Bloom, S. Bose, J. Butt, D.R. Claes, A. Dominguez, M. Eads, J. Keller,

I. Kravchenko, J. Lazo-Flores, H. Malbouisson, S. Malik, G.R. Snow

State University of New York at Buffalo, Buffalo, U.S.A.

U. Baur, A. Godshalk, I. Iashvili, S. Jain, A. Kharchilava, A. Kumar, S.P. Shipkowski,

K. Smith

Northeastern University, Boston, U.S.A.

G. Alverson, E. Barberis, D. Baumgartel, M. Chasco, J. Haley, D. Nash, D. Trocino,

D. Wood, J. Zhang

Northwestern University, Evanston, U.S.A.

A. Anastassov, A. Kubik, N. Mucia, N. Odell, R.A. Ofierzynski, B. Pollack, A. Pozdnyakov,

M. Schmitt, S. Stoynev, M. Velasco, S. Won

University of Notre Dame, Notre Dame, U.S.A.

L. Antonelli, D. Berry, A. Brinkerhoff, M. Hildreth, C. Jessop, D.J. Karmgard, J. Kolb,

K. Lannon, W. Luo, S. Lynch, N. Marinelli, D.M. Morse, T. Pearson, R. Ruchti,

J. Slaunwhite, N. Valls, M. Wayne, M. Wolf

The Ohio State University, Columbus, U.S.A.

B. Bylsma, L.S. Durkin, A. Hart, C. Hill, R. Hughes, K. Kotov, T.Y. Ling, D. Puigh,

M. Rodenburg, C. Vuosalo, G. Williams, B.L. Winer

– 28 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Princeton University, Princeton, U.S.A.

N. Adam, E. Berry, P. Elmer, D. Gerbaudo, V. Halyo, P. Hebda, J. Hegeman, A. Hunt,

P. Jindal, D. Lopes Pegna, P. Lujan, D. Marlow, T. Medvedeva, M. Mooney, J. Olsen,

P. Piroué, X. Quan, A. Raval, B. Safdi, H. Saka, D. Stickland, C. Tully, J.S. Werner,

A. Zuranski

University of Puerto Rico, Mayaguez, U.S.A.

J.G. Acosta, E. Brownson, X.T. Huang, A. Lopez, H. Mendez, S. Oliveros, J.E. Ramirez

Vargas, A. Zatserklyaniy

Purdue University, West Lafayette, U.S.A.

E. Alagoz, V.E. Barnes, D. Benedetti, G. Bolla, D. Bortoletto, M. De Mattia, A. Everett,

Z. Hu, M. Jones, O. Koybasi, M. Kress, A.T. Laasanen, N. Leonardo, V. Maroussov,

P. Merkel, D.H. Miller, N. Neumeister, I. Shipsey, D. Silvers, A. Svyatkovskiy, M. Vidal

Marono, H.D. Yoo, J. Zablocki, Y. Zheng

Purdue University Calumet, Hammond, U.S.A.

S. Guragain, N. Parashar

Rice University, Houston, U.S.A.

A. Adair, C. Boulahouache, K.M. Ecklund, F.J.M. Geurts, B.P. Padley, R. Redjimi,

J. Roberts, J. Zabel

University of Rochester, Rochester, U.S.A.

B. Betchart, A. Bodek, Y.S. Chung, R. Covarelli, P. de Barbaro, R. Demina, Y. Eshaq,

A. Garcia-Bellido, P. Goldenzweig, J. Han, A. Harel, D.C. Miner, D. Vishnevskiy,

M. Zielinski

The Rockefeller University, New York, U.S.A.

A. Bhatti, R. Ciesielski, L. Demortier, K. Goulianos, G. Lungu, S. Malik, C. Mesropian

Rutgers, the State University of New Jersey, Piscataway, U.S.A.

S. Arora, A. Barker, J.P. Chou, C. Contreras-Campana, E. Contreras-Campana,

D. Duggan, D. Ferencek, Y. Gershtein, R. Gray, E. Halkiadakis, D. Hidas, A. Lath,

S. Panwalkar, M. Park, R. Patel, V. Rekovic, J. Robles, K. Rose, S. Salur, S. Schnetzer,

C. Seitz, S. Somalwar, R. Stone, S. Thomas

University of Tennessee, Knoxville, U.S.A.

G. Cerizza, M. Hollingsworth, S. Spanier, Z.C. Yang, A. York

Texas A&M University, College Station, U.S.A.

R. Eusebi, W. Flanagan, J. Gilmore, T. Kamon58, V. Khotilovich, R. Montalvo,

I. Osipenkov, Y. Pakhotin, A. Perloff, J. Roe, A. Safonov, T. Sakuma, S. Sengupta,

I. Suarez, A. Tatarinov, D. Toback

Texas Tech University, Lubbock, U.S.A.

N. Akchurin, J. Damgov, P.R. Dudero, C. Jeong, K. Kovitanggoon, S.W. Lee, T. Libeiro,

Y. Roh, I. Volobouev

– 29 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

Vanderbilt University, Nashville, U.S.A.

E. Appelt, C. Florez, S. Greene, A. Gurrola, W. Johns, C. Johnston, P. Kurt, C. Maguire,

A. Melo, P. Sheldon, B. Snook, S. Tuo, J. Velkovska

University of Virginia, Charlottesville, U.S.A.

M.W. Arenton, M. Balazs, S. Boutle, B. Cox, B. Francis, J. Goodell, R. Hirosky,

A. Ledovskoy, C. Lin, C. Neu, J. Wood, R. Yohay

Wayne State University, Detroit, U.S.A.

S. Gollapinni, R. Harr, P.E. Karchin, C. Kottachchi Kankanamge Don, P. Lamichhane,

A. Sakharov

University of Wisconsin, Madison, U.S.A.

M. Anderson, M. Bachtis, D. Belknap, L. Borrello, D. Carlsmith, M. Cepeda, S. Dasu,

L. Gray, K.S. Grogg, M. Grothe, R. Hall-Wilton, M. Herndon, A. Hervé, P. Klabbers,

J. Klukas, A. Lanaro, C. Lazaridis, J. Leonard, R. Loveless, A. Mohapatra, I. Ojalvo,

F. Palmonari, G.A. Pierro, I. Ross, A. Savin, W.H. Smith, J. Swanson

†: Deceased

1: Also at Vienna University of Technology, Vienna, Austria

2: Also at National Institute of Chemical Physics and Biophysics, Tallinn, Estonia

3: Also at Universidade Federal do ABC, Santo Andre, Brazil

4: Also at California Institute of Technology, Pasadena, U.S.A.

5: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland

6: Also at Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau,

France

7: Also at Suez Canal University, Suez, Egypt

8: Also at Zewail City of Science and Technology, Zewail, Egypt

9: Also at Cairo University, Cairo, Egypt

10: Also at Fayoum University, El-Fayoum, Egypt

11: Also at Ain Shams University, Cairo, Egypt

12: Now at British University, Cairo, Egypt

13: Also at Soltan Institute for Nuclear Studies, Warsaw, Poland

14: Also at Université de Haute-Alsace, Mulhouse, France

15: Now at Joint Institute for Nuclear Research, Dubna, Russia

16: Also at Moscow State University, Moscow, Russia

17: Also at Brandenburg University of Technology, Cottbus, Germany

18: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary

19: Also at Eötvös Loránd University, Budapest, Hungary

20: Also at Tata Institute of Fundamental Research - HECR, Mumbai, India

21: Also at University of Visva-Bharati, Santiniketan, India

22: Also at Sharif University of Technology, Tehran, Iran

23: Also at Isfahan University of Technology, Isfahan, Iran

24: Also at Plasma Physics Research Center, Science and Research Branch,

Islamic Azad University, Teheran, Iran

– 30 –



J
H
E
P
0
8
(
2
0
1
2
)
0
2
6

25: Also at Facoltà Ingegneria Università di Roma, Roma, Italy

26: Also at Università della Basilicata, Potenza, Italy

27: Also at Università degli Studi Guglielmo Marconi, Roma, Italy

28: Also at Università degli studi di Siena, Siena, Italy

29: Also at University of Bucharest, Faculty of Physics, Bucuresti-Magurele, Romania

30: Also at Faculty of Physics of University of Belgrade, Belgrade, Serbia

31: Also at University of Florida, Gainesville, U.S.A.

32: Also at University of California, Los Angeles, Los Angeles, U.S.A.

33: Also at Scuola Normale e Sezione dell’ INFN, Pisa, Italy

34: Also at INFN Sezione di Roma; Università di Roma ”La Sapienza”, Roma, Italy

35: Also at University of Athens, Athens, Greece

36: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom

37: Also at The University of Kansas, Lawrence, U.S.A.

38: Also at Paul Scherrer Institut, Villigen, Switzerland

39: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia

40: Also at Gaziosmanpasa University, Tokat, Turkey

41: Also at Adiyaman University, Adiyaman, Turkey

42: Also at Izmir Institute of Technology, Izmir, Turkey

43: Also at The University of Iowa, Iowa City, U.S.A.

44: Also at Mersin University, Mersin, Turkey

45: Also at Ozyegin University, Istanbul, Turkey

46: Also at Kafkas University, Kars, Turkey

47: Also at Suleyman Demirel University, Isparta, Turkey

48: Also at Ege University, Izmir, Turkey

49: Also at School of Physics and Astronomy, University of Southampton, Southampton,

United Kingdom

50: Also at INFN Sezione di Perugia; Università di Perugia, Perugia, Italy

51: Also at University of Sydney, Sydney, Australia

52: Also at Utah Valley University, Orem, U.S.A.

53: Also at Institute for Nuclear Research, Moscow, Russia

54: Also at University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear

Sciences, Belgrade, Serbia

55: Also at Argonne National Laboratory, Argonne, U.S.A.

56: Also at Erzincan University, Erzincan, Turkey

57: Also at KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary

58: Also at Kyungpook National University, Daegu, Korea

– 31 –


	Introduction
	The CMS detector
	Signal simulation
	Event selection
	Backgrounds
	Systematic uncertainty
	Search results
	Excluded region in the m(tilde(g)) - m(tilde(x)*0) plane
	Summary
	The CMS collaboration