Search for new long-lived particles at sqrt(s)=13 TeV

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Physics

Letters

B

www.elsevier.com/locate/physletb

Search

for

new

long-lived

particles

at

√

s

=

13 TeV

.TheCMS Collaboration

CERN,Switzerland

a r t i c l e i n f o a b s t ra c t

Articlehistory:

Received24November2017

Receivedinrevisedform19February2018 Accepted7March2018

Availableonline14March2018 Editor:M.Doser

Keywords:

CMS Physics

Long-livedparticles

Asearchforlong-livedparticleswasperformedwithdatacorrespondingtoanintegratedluminosityof 2.6 fb−1 _{collectedatacenter-of-massenergyof13 TeVbythe CMSexperimentin2015. Theanalysis}

exploits two customized topological trigger algorithms, and uses the multiplicityof displaced jetsto searchforthepresenceofasignaldecayoccurringatdistancesbetween1and1000 mm.Theresultscan beinterpretedinavarietyofdifferentmodels.Forpair-producedlong-livedparticlesdecayingtotwob quarksandtwoleptonswithequaldecayratesbetweenleptonflavors,crosssectionslargerthan2.5 fb are excludedforproperdecaylengthsbetween70–100 mmforalong-livedparticlemassof1130 GeV at95%confidence.Foraspecificmodelofpair-produced,long-livedtopsquarkswithR-parityviolating decaystoabquarkandalepton,massesbelow550–1130 GeVareexcludedat95%confidenceforequal branchingfractionsbetweenleptonflavors,dependingonthesquarkdecaylength.Thismassboundis themoststringenttodatefortopsquarkproperdecaylengthsgreaterthan3 mm.

©2018TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/).FundedbySCOAP3_.

1. Introduction

The observation ofphysics beyondthe standard model (BSM) isone ofthemainobjectives oftheATLAS andCMSexperiments attheCERNLHC.Withno signalyetobserved,theseexperiments have placed stringent bounds on BSM models. The majority of these searches focus on particles with lab frame decay lengths of cτ <1 mm and incorporate selection requirements that re-ject longer-lived particle decays. This leaves open the possibility thatlong-livedparticlescouldbeproducedbutremainundetected. ThepresentanalysisexploitsinformationoriginatingfromtheCMS calorimeters to reconstruct jets andmeasure their energies. The informationfromreconstructedtracks,inparticularthetransverse impactparameter,isusedtodiscriminatethesignalofajetwhose origin is displaced with respect to the primary vertex, from the backgroundofordinary multijetevents.Theanalysisisperformed on data from proton–protoncollisions at √s=13 TeV, collected with the CMS detector in 2015. The data set corresponds to an integrated luminosity of 2.6 fb−1_{. Results for similar signatures} at√s=8 TeVhavebeen reportedby ATLAS [1–3], CMS [4], and LHCb [5,6].InthisLetter,wepresentanew,moregeneralapproach to searching forlong-lived particles decaying to combinationsof jetsandleptons,whichisinclusiveineventtopologyanddoesnot requirethereconstructionofadisplacedvertex.

 _{E-mailaddress:cms-publication-committee-chair@cern.ch.}

2. TheCMSdetector

The central feature of the CMS apparatus is a superconduct-ing solenoidof6 m internal diameter,providing amagneticfield of3.8 T.Withinthe solenoidvolumeare asiliconpixel andstrip tracker,aleadtungstatecrystalelectromagneticcalorimeter(ECAL), andabrassandscintillatorhadron calorimeter(HCAL),each com-posed ofa barrelandtwo endcapsections. Forwardcalorimeters extendthepseudorapidity(η)coverageprovidedbythebarreland endcapdetectors.Muonsaremeasuredingas-ionizationdetectors embeddedinthesteelflux-returnyokeoutsidethesolenoid.

The silicon tracker measures charged particles with|η| <2.5. Itconsistsofsiliconpixelsandsiliconstripdetectormodules.The innermostpixel(strip) layerisataradial distanceof4.3(44)cm fromthebeamline.

The ECALconsistsoflead tungstatecrystalsandprovides cov-erage in |η| <1.48 in a barrelregion (EB) and 1.48<|η| <3.0 in two endcap regions (EE). A preshower detector composed of two planes ofsilicon sensors interleavedwitha total of3 radia-tionlengthsofleadislocatedinfrontoftheEE.Theinnerfaceof theECALisataradialdistanceof129 cmfromthebeamline.

Intheregion|η| <1.74,theHCALcellshavewidthsof0.087in pseudorapidityand0.087radiansinazimuth(φ).Inthe η–φplane, andfor|η| <1.48,the HCALcellsmap onto5×5 arraysofECAL crystals to form calorimeter towers projecting radially outwards fromclosetothenominalinteractionpoint.For1.74<|η| <3.00, thecoverage ofthetowers increasesprogressivelyto amaximum

https://doi.org/10.1016/j.physletb.2018.03.019

0370-2693/©2018TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).Fundedby SCOAP3_.

of0.174inηandφ.Withineachtower,theenergydepositsin ECALandHCALcellsaresummedtodefine thecalorimetertower energiesandaresubsequentlyusedtoprovidetheenergiesofjets. TheinnerfaceoftheHCALisataradial distanceof179 cmfrom thebeamline.

Foreach event, jetsare clusteredfromenergydeposits inthe calorimeters,using the FastJet [7] implementationof the anti-kT algorithm [8], with the distance parameter 0.4. Tracks that are withinR=(η)2_{+ (φ)}2_{<0.4 ofajet areconsidered tobe} associatedwiththejet.

Events ofinterest are selected usinga two-tieredtrigger sys-tem [9]. Thefirstlevel,composedofcustomhardware processors, usesinformationfromthecalorimetersandmuondetectorsto se-lecteventsatarateofaround 100 kHzwithin atime intervalof lessthan4 μs. Thesecond level,knownas thehigh-level trigger (HLT),consistsofafarmofprocessorsrunningaversionofthefull eventreconstruction software optimized for fast processing, and reducestheeventratetoaround1 kHzbeforedatastorage.

AmoredetaileddescriptionoftheCMSdetector,togetherwith adefinitionofthecoordinatesystemusedandtherelevant kine-maticvariables,canbefoundinRef. [10].

3. Datasetsandsimulatedsamples

Events are selected using two dedicated HLT algorithms, de-signedtoidentifyeventswithdisplacedjets.Bothalgorithmshave a requirementon HT, which is definedasthe scalar sumof the transversemomentumpTofthejetsintheevent,consideringonly jetswith pT>40 GeV and |η| <3.0.The inclusivealgorithm ac-ceptseventswith HT>500 GeV andatleasttwo jets, each with

pT>40 GeV,|η| <2.0,andnomorethantwo associatedprompt tracks. Tracks are classified as prompt if their transverse impact parameterrelativeto thebeamline, IP2D_{,is lessthan 1 mm.The} exclusive algorithm requires HT>350 GeV and at leasttwo jets withpT>40 GeV,|η| <2.0,nomorethantwoassociatedprompt tracks,andatleastoneassociatedtrackwithIP2D_>5σ

IP2D,where σ_IP2D is the calculated uncertainty in IP2D. Data collected by al-gorithmswithidenticalHT requirementsandnotracking require-ments areused to studytheperformance of theonline selection algorithms.

Events are selectedoffline by requiringat leasttwo jetswith pT>60 GeV and|η| <2.0.Twoclassesofeventsare considered: events (i) passing the inclusiveonline algorithm and with HT> 650 GeV and(ii)passing theexclusiveonlinealgorithm andwith HT>450 GeV. Combining these two classesof events results in 786 002 unique events. We refer to these events as passing the eventselectionorsimply“Selection”intheefficiencytables.

Themainsourceofbackgroundeventsoriginatesfrommultijet production. The properties of this background process are stud-iedusingasimulatedmultijetsample,generatedwith MadGraph5 [11] and interfaced with pythia8 [12] for parton showering and hadronization. The NNPDF 2.3 [13] parton distribution functions (PDFs)are usedto model theparton momentum distribution in-sidethecollidingprotons.Theeventsimulationincludestheeffect of additional proton–proton collisions in the same bunch cross-ingand inbunch crossingsnearbyin time, referred toaspileup. Simulatedsamplesarereweightedtomatchthepileupprofile ob-servedindata.The detectorresponse issimulatedindetailusing Geant4 [14].

Theanalysisisinterpretedwithasetofbenchmarksignal mod-els.TheJet-Jetmodelpredictspair-producedlong-livedscalar neu-tralparticles X0_{,each decayingto a quark–antiquark pair,where} possible pairs include u, d, s, c, and b quarks. The two scalars areproduced through a 2→2 scattering process, mediated by a Z∗ propagator, and the decay rate to each flavor is assumed to

be the same. The resonance mass m_X0 and average proper de-caylengthcτ0 arevaried between50and1500 GeVandbetween 1and2000 mm,respectively.The modelresembleshiddenvalley modelsthat producelong-livedneutralfinal states[15]. The trig-gerefficienciesformX0=300 GeV andcτ0=1,30,and1000 mm are 30%,81%, and42%, respectively.Forexample,the trigger effi-cienciesare2%,14%,and92%forcτ0=30 mm andmX0=50,100, and1000 GeVrespectively.Thetriggerefficiencyiscalculatedfrom thetotalnumberofeventspassing onlythelogicalORofthetwo triggerpaths.

The B-Lepton model contains pair-produced long-lived top squarksinR-parity[16] violatingmodelsofsupersymmetry(SUSY) [17]. Each top squark decays to one b quark and a lepton, with equal decay rates to each of the three lepton flavors. The reso-nance massm_t andproper decay length cτ0 are varied between 300and1000 GeVandbetween1and1000 mm,respectively.For example,thetriggerefficienciesform_t=300 GeV andcτ0=1,30, and1000 mmare15%,41%,and23%,respectively.Thetrigger effi-cienciesare64%,71%,and74%forcτ0=30 mmandmt=500,700, and1000 GeV,respectively.

Variations of these models with modified branching fractions are also investigated. The Light-Light model is the Jet-Jet model excludingdecaystobquarks(equal decaystolighterquarks) and the B-Muon, B-Electron, andB-Tau models are derived from the B-Leptonmodelwith100%branchingfractiontomuons,electrons, and τ leptons, respectively. Both leptonic andhadronic τ lepton decaysareincludedintheB-Tauinterpretation.Allsignalsamples aregeneratedwith pythia8,withthesameconfigurationasforthe multijetsample.

4. Eventselectionandinclusivedisplaced-jettagger

In general, events contain multiple primary vertex (PV) can-didates, corresponding to pileup collisions occurringin the same proton bunch crossing. The PV reconstruction employs Gaussian constraints on thereconstructed position based on theluminous region, which is evaluated from the reconstructed PVs in many events. A description of the PV reconstruction can be found in Ref. [18]. The displaced-jet identification variables utilize the PV withthehighest p2

T sumofthe constituenttracks.Theresults of theanalysisarefoundtobeinsensitivetothechoiceofthemethod usedto selectthePV,since theuncertaintyinthetransverse po-sition ofthe primary vertexissmall relative tothe signal model decaylengths.

The analysisutilizes a dedicated taggingalgorithm to identify displaced jets. Foreach jet, the algorithm takes asinput the re-constructed tracks within R <0.4 of the jet. All tracks with pT>1 GeV thatare selectedby alliterations oftrack reconstruc-tion are considered. A detailed list of requirements for the CMS trackcollection can be found elsewhere[18]. Three variablesare considered for each jet in theevent. The firstvariable quantifies howlikelyitisthatthejetoriginatesfromagivenPV.Foragiven jet, αjet(PV)isdefinedforeachPVas

αjet(PV)=  tracks∈PVptracksT  tracksptracksT , (1)

where the sumin the denominator is over all tracks associated withthejetandthesuminthenumeratorisoverjustthesubset ofthesetracksoriginatingfromthegivenPV.Thetaggingvariable αmax isthelargestvalueof αjet(PV)forthejet.

Thesecondvariablequantifiesthesignificanceofthemeasured transversedisplacementforthejet.Foreachtrackassociatedwith the jet, the significance of the track’s transverse impact param-eter, IP2D

Fig. 1. Comparisonofdistributionsforthedisplaced-jettaggingvariablesαmax(left),IP2D

sig(center),and 2D (right)indataandsimulation.Thedatadistributions(circles)

arecomparedtotheexpectedbackgrounddistributionsfrommultijetevents(squares)andseveralJet-Jetbenchmarkmodels(dottedhistograms)ofpair-producedlong-lived neutralscalarparticleswithmX0=700 GeV and differentvaluesofcτ0.Theverticallinesdesignatethevalue oftherequirementfor thechosendisplaced-jettag.The directionofthearrowindicatesthevaluesincludedintherequirement.Alldistributionshaveunitnormalization.

Table 1

Signalefficiencies(in%)formX0=mt=300 GeV forvariousvaluesofcτ0fortheJet-JetandB-Leptonmodels.Selectionrequirementsarecumulativefromthefirstrowto

thelast. Jet-Jet cτ0[mm] 1 10 100 1000 ≥2 tags 2.33±0.15 39.49±0.63 54.54±0.74 14.58±0.38 Trigger 2.16±0.15 38.12±0.62 39.32±0.63 8.07±0.28 Selection 2.09±0.14 37.09±0.61 36.53±0.60 6.67±0.26 ≥3 tags 0.17±0.04 14.14±0.38 16.72±0.41 1.36±0.12 ≥4 tags 0.01±0.01 4.73±0.22 4.71±0.22 0.17±0.04 B-Lepton cτ0[mm] 1 10 100 1000 ≥2 tags 0.45±0.02 15.82±0.13 31.52±0.19 8.55±0.10 Trigger 0.29±0.02 11.45±0.11 17.08±0.14 3.22±0.06 Selection 0.27±0.02 9.91±0.11 13.33±0.12 2.08±0.05 ≥3 tags 0.02±0.01 2.46±0.05 3.81±0.07 0.37±0.02 ≥4 tags – 0.30±0.02 0.48±0.02 0.03±0.01

uncertainty. The tagging variable IP2D

sig is the median of the IP2Dsig distributionofalltracksinajet.

Thethirdvariablequantifiestheangulardifferencebetweenthe emission angle of a given track in a jet and the parent particle flightdirection.Foreachtrackassociatedwiththejet, 2Dis com-putedastheanglebetweenthe trackpT= (px,py) atthe track’s innermosthit andthevectorconnectingthechosenPVtothishit inthetransverseplane.Thetaggingvariable 2D isthemedianof the 2Ddistributionforthetracksassociatedwiththejet.

It should be noted that leptons giving riseto calorimeter en-ergydeposits(tauleptonsandelectrons)willalsobeclassifiedas “displacedjets”, iftheassociatedtrack(s)satisfiesthetagging cri-teria,andthuscontributetothesearchsensitivity.Additionally,by not requiringthe reconstruction ofa displacedvertex, the analy-sisisbecomessensitivetopair-producedlong-liveddecayswitha singlereconstructedtrackperdecay.

Fig.1showsthedistributionsofthethreetaggingvariablesfor dataevents,simulatedmultijetevents,andsimulatedsignalevents withm_X0=700 GeV andseveralvaluesofcτ0.Notethatany mis-modeling resulting fromthe multijet background doesnot affect theanalysisbecausethebackgroundestimateisderivedfromdata. Simulationofthemultijetbackgroundonlydescribesmisidentified displacedjets.

The displaced-jet identification criteria are αmax < 0.05, log10(IP2Dsig)>1.5,andlog10( 2D)>−1.6.Thisselectionwas cho-senbyselectingparametersthatyieldedthebestdiscovery

sensi-tivityfortheJet-Jetmodelacross allgenerateddecaylengthsand masses.

Theaveragedisplaced-jettaggingefficiencywithnotrigger se-lectionapplied form_X0=700 GeV is 4%forcτ0=1 mm,57%for

cτ0=30 mm, and 33% for cτ0=1000 mm. For cτ0>1000 mm, the long-lived particles typically decay beyond the tracker. For cτ0<3 mm,theexperimentalsignatureforsignaleventsbecomes increasingly difficult to distinguish from that of background b quarkjets.

The search isperformedby applyingthe selection criteria de-scribed above and by counting the number of tagged displaced jets, Ntags.In additionto theonlineandoffline requirements de-scribed inSection 3, theanalysissignalregion requires Ntags≥2. Efficiencies arereportedforthe Jet-JetandB-Leptonmodels asa function of decay length with fixed mass (Table 1) aswell as a functionofmasswithfixeddecaylength(Table2).Efficienciesfor the Light-Light, B-Tau, B-Electron, andB-Mu models are included insupplementalmaterialasTables 1and 2.

5. Backgroundprediction

Background events arise from jets containing tracks that are mismeasured as displaced and jets containing tracks from the weakdecaysofstrange,charm,andbottomhadrons.

Tomaintainthestatisticalindependenceoftheeventsthat are usedtoperformthepredictionandtheeventsinthesignalregion, themisidentificationrateismeasuredinacontrolsampledefined

Table 2

Signalefficiencies(in%)fortheJet-JetandB-Leptonmodelswithcτ0=30 mm andforvariousvaluesofmass.Selectionrequirementsarecumulativefromthefirstrowto thelast. Jet-Jet mX0 [GeV] 50 100 300 1000 1500 ≥2 tags 2.71±0.10 14.80±0.22 54.24±0.74 79.93±0.89 82.55±0.91 Trigger 0.50±0.04 5.39±0.13 46.41±0.68 74.05±0.86 77.65±0.88 Selection 0.30±0.03 3.70±0.11 44.75±0.67 73.99±0.86 77.53±0.88 ≥3 tags 0.05±0.01 1.09±0.10 20.87±0.46 49.42±0.70 55.28±0.74 ≥4 tags – 0.22±0.03 6.81±0.26 25.45±0.50 32.26±0.57 B-Lepton mt[GeV] 300 600 800 1000 ≥2 tags 31.52±0.19 47.32±0.23 52.53±0.24 55.88±0.35 Trigger 17.08±0.14 35.03±0.20 40.40±0.21 43.14±0.30 Selection 14.70±0.13 32.34±0.19 36.94±0.20 39.26±0.29 ≥3 tags 4.11±0.07 10.76±0.11 13.29±0.12 15.00±0.18 ≥4 tags 0.55±0.03 1.83±0.05 2.69±0.05 3.09±0.08

Fig. 2. Thefractionofjetspassingthedisplaced-jettaggingcriteriaasafunctionof thenumberoftracksassociatedwiththejet.Theresultsarefromdataeventswith

Ntags≤1,collectedwiththedisplaced-jettriggersandpassingtheofflineselection

criteria.

aseventswithNtags≤1 (asshowninFig.2),whilethesignal re-gionrequiresNtags≥2.Additionally,thiscontrolsampledefinition limitssignal contamination. There are 1391 events in data with Ntags=1. Thesize ofthe bias introduced by onlymeasuring the misidentificationrateineventswithNtags≤1 is quantifiable.For the chosen tag requirement, the effect of removing events with Ntags>1 onthepredictednumberoftwotageventsisnegligible (0.4%)comparedtothestatisticaluncertaintyoftheprediction.

Since the proportion of tracks identified as being displaced is small and approximately constant, the likelihood of tagging a nondisplacedjetasadisplacedjetdecreases approximately expo-nentiallywiththenumberoftracksassociatedwiththejet,Ntracks. Fig.2showsthe fractionofjetsthat aretagged asdisplacedjets indataasafunction ofNtracks.Thisfunctionisthe misidentifica-tionrateoftaggingapromptjetasdisplaced(assumingnosignal contamination)andis interpreted asthe probability p(Ntracks)of beingtagged.Thisparameterizationallows an eventby event es-timationoftheprobabilityoftagginganymultiplicity ofdisplaced jets.

Becauseof thehighjet production crosssection, even though the misidentification rate is small, events with one tagged dis-placed jet are completely dominated by standard model back-grounds, and signal contamination can be ignored, even if the associatedcrosssectionislarge.Thisisexplicitlyverifiedwith sig-nalinjectiontests,whicharediscussedbelow.

The misidentification rate is used to predict the probability P(Ntags) foran eventto have Ntags tagged jets. For instance, for

aneventm withthreejets j1, j2,and j3,thereisonejet configu-rationwithnotags,withaprobability:

Pm(Ntags=0)= (1−p1)(1−p2)(1−p3),

where pi=p(Ntracks(ji)).Similarly, there are threejet

configura-tionsforthissameeventtohaveNtags=1:

Pm(Ntags=1)=p1(1−p2)(1−p3)+ (1−p1)p2(1−p3) + (1−p1)(1−p2)p3.

TheprobabilityoffindingNtags tagsinthem eventis:

Pm(Ntags)=  jet-configs  i∈tagged pi  k∈nontagged (1−pk). (2)

Tagged jetsenter the product as pi andnontagged jetsenter as

(1−pi).Equation (2) isusedtocompute Pm(Ntags),underthe as-sumptionthatthesampledoesnotcontainanysignal.Thenumber ofeventsexpectedforagivenvalueofNtags iscomputedas

Nevents(Ntags)= 

m

Pm(Ntags), (3)

wherem runsonly overevents withfewerthan two taggedjets. ThepredictionisthencomparedtotheobservedNtagsmultiplicity ineventswithtwo ormoretaggedjets, toassessthepresenceof asignal.

We validate this procedure in the absence (background-only test) andpresence (signalinjection test)of a signal, using simu-latedevents.

The background-only test is performed by predicting the tag multiplicity fromthe simulatedmultijet sample, usingthe distri-butionobtainedforthemisidentificationrate.Inordertopopulate the large-Ntags region of the distribution,a looser version of the displaced-jet taggerisemployed inthistest.Theloose displaced-jet identification criteria are αmax<0.5, log10(IP2Dsig)>0.4, and log₁₀( 2D)>−1.7.Theaveragemisidentificationrateoftheloose (chosen)tagdefinitionis2.6% (0.05%).Theloosedefinition require-ments were relaxed until a minimal number of two tag events wereavailable toperformthebackground-onlytest.Thefull sam-ple ofeventspassing theeventselection is dividedinto multiple independentsamplesandthebackgroundpredictionvalidated.The predictedbackgroundof Ntags eventsinsimulatedmultijetevents isfoundtobeconsistentwiththeobservednumberofevents.The associated pull distributions are found to havemean 0and vari-ance1asexpectedintheidealcase.

Table 3

Summaryofthesignalsystematicuncertainties.Whenthe uncer-taintydependsonthespecificfeaturesofthemodels(mass,decay length,anddecaymodeofthelong-livedparticle)arangeisquoted, whichreferstothecomputeduncertaintyforNtags=2 events.

Signal systematic uncertainty Effect on yield

HTtrigger inefficiency 5%

Jet pTtrigger inefficiency 5%

Trigger online tracking modeling 1–35% Integrated Luminosity 2.3% Acceptance due to the PDF choice 1–6% Displaced-jet tag variable modeling 1–30%

Thesignalinjectiontestisperformedbyaddingeventsof pair-produced resonances decaying to two jets to the multijet sam-ple and repeating the procedure described above. In this case, the chosen displaced-jet tagger is used. The injected signal has m_X0=700 GeV and cτ0=10 mm with a cross section varied in therangefrom30 fb to 3 pb.The jet probabilityis computedas inthedata,wherenopriorknowledgeofthenatureoftheevents (signalorbackground)isavailable.Inthiscase, the misidentifica-tion rate is derived fromthe mixed sample itself, including the contamination from the injected signal sample. The signal con-tamination is found to have a minimal impact on the predicted numberof events in thesignal region. Forexample, withan in-jected signal cross section of30 fb, 19 eventsare observed with twotags,whilethetwotagpredictionisconsistentwiththe pre-dictionsobtainedforzeroinjectedevents:Nevents(Ntags≥2)=1.3. Asanotherexample,withaninjectionsignalcrosssectionof3 pb, no three tag eventsare predicted, while 1520events withthree tags are observed. Given the insensitivity of the predicted back-groundtolarge amounts ofinjectedsignal, theanalysisis robust tosignalcontaminationofthecontrolregion.

6. Systematicuncertainties

6.1. Backgroundsystematicuncertainties

Thereisanuncertaintyintheestimatedbackgroundlevel asso-ciatedwiththechoice ofmethodused.Thisuncertaintyis evalu-atedby repeating thebackgroundpredictionprocedure described inSection 5 usingthe looserversion ofthe displaced-jettagging algorithm. The result is compared with that obtained using the nominalmethod and the observed difference of7.5% is taken as thesystematicuncertaintyfromthissource.Thisvalueforthe un-certaintyisusedalsoforthethreeormoretagscase.

The statistical uncertainty in the measured misidentification rateas a function of Ntracks is propagated to the predicted Ntags distribution as a systematic uncertainty. This systematic uncer-tainty is calculated foreach tag multiplicity bin. The uncertainty forthetwotagbinis13%.

6.2. Signalsystematicuncertainties

All signal systematic uncertainties are calculated individually foreachmodel,foreachmassanddecaylengthpoint,andforeach valueofNtags inthesignalregion.Incaseswheretheuncertainty depends on the mass, decay length, and/or decay mode of the long-livedparticle,arangeis quoted,referring tothe uncertainty for Ntags=2 events. A summary of the systematic uncertainties associatedwiththesignalisgiveninTable3.

Theuncertaintyinthe triggeremulation ismeasuredby com-paringthepredictedefficiencyforsimulatedmultijeteventswith thatmeasured fordatacollected withaloose HT trigger. The ob-served difference at theoffline HT threshold(5%) is taken asan

Table 4

Thepredictedandobservednumberofeventsasafunctionofthenumberoftagged displacedjets.Thepredictionisbasedonthemisidentificationratederivedfrom eventswithfewerthantwotags.Thefulleventselectionisapplied.Theuncertainty correspondstothetotalbackgroundsystematicuncertainty.

Ntags Expected Observed

2 1.09±0.16 1

≥3 (4.9±1.0)×10−4 ₀

estimate oftheuncertaintyintheemulation oftheonlineHT re-quirement.Similarly,theuncertaintyinducedbytheonlineversus offlinejetacceptanceisobtainedfromtheshiftinthetrigger effi-ciencywhentheofflineminimumjet pT requirementisincreased from60to80 GeV(5%).

Thesystematicuncertaintyinthemodelingoftheonline track-ing efficiency is obtained by studying the online regional track reconstructionindataandinsimulation.TheonlinevaluesofIP2D and IP2D

sig are varied by themagnitude ofthe mismodeling found in events collected by control sample triggers consisting of only an HT requirement(HT>425 and HT>275).Thenewvaluesare usedtodetermineiftheeventwouldstill passatleastoneofthe trigger pathsandits associatedoffline HT requirement. The Ntags distribution is recalculated with the valuesvaried up and down. TherelativechangeinthenumberofeventsperNtags binistaken asthesystematicuncertainty.ForNtags=2,thisuncertaintyvaries from1to35%.

Thesystematicuncertaintyintheluminosityis2.3%[19]. The uncertainty arising from the choice of PDFs for pair-produced particles with masses in the range of 50–1500 GeV is found to be 1–6%. An ensemble of alternative PDFs is sampled fromtheoutputoftheNNPDFfit.Eventsarereweightedaccording to the ratio betweenthese alternativePDF sets andthe nominal ones. The distribution of the signal prediction forthese PDF en-semblesisusedtoquantifythisuncertainty.

The systematicuncertainty inthe modeling ofthe jet tagging variables inthe signal simulation samples is estimatedfrom the displacedtrackmodelinginmultijeteventsindataandsimulation. The mismodelingofthemeasured valueof 2D andIP2D_sig for sin-gletracksispropagatedtothefinaltagdistributionbyvaryingthe individual measuredvaluesinsimulation bythedifference inthe measuredvalue relativetodata(3–10%).Thetaggingvariablesare then recalculated. The Ntags distribution is recalculated with the newvalues.Thesystematicuncertaintyisassignedasthe relative changeinthenumberofeventsforeachNtagsbin.Forthetwotag bin,this variesfrom1to 30% depending onthe massanddecay length.Themismodeling of αmax isfoundtohaveanegligible ef-fectonthesignalefficiency,astherequirementisrelativelyloose.

7. Resultsandinterpretation

Thenumericalvaluesfortheexpectedandobservedyields are summarizedinTable 4.The observedyields arefoundto be con-sistent with the predictedbackground, within the statistical and systematic uncertainties. No evidencefor a signal atlarge values ofNtags isobserved.

Exclusionsforeachmodelareobtainedfromthepredictedand observed eventyields inTable4andthesignalefficiencies in Ta-bles 1 and 2 and Tables 1 and 2 in supplemental material. All boundsare derived at95% confidencelevel (CL)accordingto the CLsprescription [20–23] intheasymptoticapproximation.Foreach limitderivation,weconsidereventswithNtags≥2,using indepen-dent bins for Ntags=2 and Ntags≥3. Finer binning of the tag multiplicity for Ntags>3 is found to havea negligible effect on the expectedlimits. Crosssection upperlimitsarepresentedasa

Fig. 3. Theexcludedcrosssectionat95%CLfortheJet-Jetmodel(upperleft)andtheB-Leptonmodel(upperright)asafunctionofthemassandproperdecaylengthof theparentparticle.TheB-Leptonplotalsoshowstheexpected(observed)exclusionregionwithonestandarddeviationexperimental(theoretical)uncertainties,utilizinga NLO+NLLcalculationofthetopsquarkproductioncrosssection.Thelowerplotshowstheexcludedcrosssectionat95%CLfortheJet-Jetmodelasafunctionoftheproper decaylengthforthreeillustrativesmallervaluesofthemass.Theshadedbandsinthelowerplotrepresenttheonestandarddeviationuncertaintiesintheexpectedlimits. functionof themass andproper decaylength ofthe parent

par-ticle. Theanalysis sensitivityismaximal for cτ0 rangingfrom10 to1000 mm.Massexclusionboundsatfixeddecaylengtharealso derived bycomparing theexcluded cross section withthevalues predictedforthebenchmarkmodelsdescribedinSection3.Inthe caseofSUSYmodels,thenext-to-leadingorder(NLO)and next-to-leading logarithmic (NLL)tt∗ production cross section computed inthelarge-masslimitforallotherSUSYparticles [24–29] isused asareference.

Fig.3showstheexcludedpairproductioncrosssectionforthe Jet-Jet and B-Lepton models. The Light-Light model is shown in Figure 1ofsupplementalmaterialandhasnearlyidentical perfor-mancetothe Jet-Jetmodel.TheB-Lepton sensitivityissimilar to that observed forthe Jet-Jet model, although it is less stringent as additional jets give higher efficiency than additional leptons fromboth thetagging andtriggering perspectives. Cross sections larger than 2.5 fb are excluded at 95% CL, for cτ0 in the range 70–100 mm,whichcorrespondstotheexclusionofparentmasses below1130 GeV.

TheexclusionsfortheB-Tau,B-ElectronandB-Muonmodelsare showninFigs. 2–4 ofsupplemental material,respectively.The B-TauandB-Electronmodelshavesimilarperformanceathighmass

with slightly stronger limits for the B-Electron model at lower mass (m_t =300 GeV) and longer decay length (cτ0>10 mm). The highest mass excluded in the B-Electron (B-Tau) model is mt=1145(1150)GeV at cτ0=70 mm, corresponding to a cross sectionof2.3 (2.2) fbat95%CL.

InthecaseoftheB-Muonmodel,theanalysisusesjets recon-structedfromcalorimetricdepositsandthetwomuonshavesmall orno associatedcalorimeterdeposits,thus the signal reconstruc-tion efficiencyandthedisplaced-jet multiplicity are smaller. This resultsinaweakerexclusionbound.Thehighestmassexcludedin theB-Muonmodelism_t=1085 GeV atcτ0=70 mm, correspond-ingtoacrosssectionupperlimitof3.5 fbat95%CL.

8. Summary

Asearchforlong-livedparticleshasbeenperformedwithdata corresponding to an integrated luminosity of 2.6 fb−1 _collected at a center-of-massenergy of13 TeV by the CMSexperiment in 2015. Thisis the first search forlong-lived particles decaying to jetfinal statesin13 TeVdataandthefirstsearch todemonstrate explicit sensitivity to long-lived particles decaying to τ leptons. Theanalysisutilizestwocustomizedtopologicaltriggeralgorithms

and an offline displaced-jet tagging algorithm, where the multi-plicity of displaced jets is used to search for the presence of a signal.Asnoexcessabovethepredictedbackgroundisfound, up-perlimitsaresetat95%confidencelevelontheproductioncross sectionforlong-livedresonancesdecayingtotwojetsortoa lep-ton and b quark. The limits are calculated as a function of the massandproper decaylength ofthelong-livedparticles.For res-onancesdecayingtoa bquark anda lepton,crosssectionslarger than2.5 fbareexcludedforproperdecaylengthsof70–100 mm. The cross section limits are also translated into mass exclusion bounds, using a calculation of the top squark production cross sectionasareference.Assumingequalleptonbranchingfractions, pair-producedlong-livedR-parityviolatingtopsquarkslighterthan 550–1130 GeVare excluded,depending onthesquarkproper de-caylength.Thismassexclusionboundiscurrentlythemost strin-gent boundavailable fortop squarkproper decaylengthsgreater than3 mm.

Acknowledgements

WecongratulateourcolleaguesintheCERNaccelerator depart-ments for the excellent performance of the LHC and thank the technicalandadministrativestaffs atCERN andatother CMS in-stitutes for their contributions to the success of the CMS effort. Inaddition,we gratefullyacknowledgethe computingcenterand personneloftheWorldwideLHCComputingGridfordeliveringso effectivelythe computinginfrastructureessential to ouranalyses. Finally, we acknowledge the enduring support for the construc-tionandoperation oftheLHCandthe CMSdetectorprovidedby thefollowingfundingagencies:BMWFWandFWF(Austria);FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MOST, and NSFC (China); COLCIEN-CIAS(Colombia);MSESandCSF(Croatia);RPF(Cyprus);SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of Fin-land,MEC,andHIP(Finland);CEAandCNRS/IN2P3(France);BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hun-gary);DAEandDST(India);IPM(Iran);SFI(Ireland);INFN(Italy); MSIPandNRF(RepublicofKorea);LAS (Lithuania);MOE andUM (Malaysia); BUAP, CINVESTAV,CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland);FCT(Portugal);JINR(Dubna);MON,ROSATOM,RAS,RFBR andRAEP(Russia);MESTD (Serbia);SEIDI,CPAN,PCTI andFEDER (Spain);SwissFundingAgencies(Switzerland);MST(Taipei); ThEP-Center, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK (Turkey);NASUandSFFR(Ukraine); STFC(United Kingdom);DOE andNSF(USA).

Individuals have received support from the Marie-Curie pro-gramandtheEuropeanResearchCouncilandEPLANET(European Union); the Leventis Foundation; the A.P. Sloan Foundation; the Alexandervon HumboldtFoundation;the BelgianFederal 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); theMinistry ofEducation,Youth andSports (MEYS)of theCzech Republic;theCouncilofScienceandIndustrialResearch,India;the HOMING PLUS programme of the Foundation for Polish Science, cofinancedfromEuropeanUnion,RegionalDevelopmentFund,the MobilityPlusprogrammeoftheMinistryofScienceandHigher Ed-ucation,theNationalScienceCenter(Poland), contractsHarmonia 2014/14/M/ST2/00428,Opus2014/13/B/ST2/02543,2014/15/B/ST2/ 03998,and2015/19/B/ST2/02861,Sonata-bis2012/07/E/ST2/01406; the National Priorities Research Program by Qatar National Re-search Fund;the Programa Clarín-COFUND delPrincipado de As-turias;the ThalisandAristeia programmescofinanced by EU-ESF andtheGreekNSRF;the RachadapisekSompotFund for

Postdoc-toralFellowship, ChulalongkornUniversity andtheChulalongkorn AcademicintoIts2ndCenturyProjectAdvancementProject (Thai-land);andtheWelchFoundation,contractC-1845.

Appendix A. Supplementarymaterial

Supplementarymaterialrelatedtothisarticlecanbefound on-lineathttps://doi.org/10.1016/j.physletb.2018.03.019.

References

[1] ATLASCollaboration,Searchforlong-lived,weaklyinteractingparticlesthat de-caytodisplacedhadronicjetsinproton–protoncollisionsat√s=8 TeV with theATLASdetector,Phys.Rev.D92(2015)012010,http://dx.doi.org/10.1103/ PhysRevD.92.012010,arXiv:1504.03634.

[2] ATLASCollaboration,Searchformassive,long-livedparticlesusingmultitrack displacedverticesordisplacedleptonpairsinppcollisionsat√s=8 TeV with theATLASdetector,Phys.Rev.D92(2015)072004,http://dx.doi.org/10.1103/ PhysRevD.92.072004,arXiv:1504.05162.

[3]ATLASCollaboration, Searchfor long-lived,massiveparticlesineventswith displacedverticesandmissingtransversemomentumin√s=13 TeV pp col-lisionswiththeATLASdetector,arXiv:1710.04901,2017.

[4] CMSCollaboration,Searchforlong-livedneutralparticlesdecayingtoquark– antiquarkpairsinproton–proton collisionsat √s=8 TeV,Phys. Rev.D91 (2015)012007,http://dx.doi.org/10.1103/PhysRevD.91.012007,arXiv:1411.6530. [5] LHCb Collaboration, Search for long-lived particles decaying to jet pairs, Eur.Phys.J.C75(2015)152,https://doi.org/10.1140/epjc/s10052-015-3344-6, arXiv:1412.3021.

[6] LHCb Collaboration, Search for Higgs-like bosons decaying into long-lived exotic particles,Eur. Phys. J. C 76(2016) 664, https://doi.org/10.1140/epjc/ s10052-016-4489-7,arXiv:1609.03124.

[7] M.Cacciari,G.P.Salam,G.Soyez,FastJetusermanual,Eur.Phys.J.C72(2012), https://doi.org/10.1140/epjc/s10052-012-1896-2,arXiv:1111.6097.

[8] M.Cacciari,G.P.Salam,G.Soyez,Theanti-ktjetclusteringalgorithm,J.High

EnergyPhys. 04(2008) 063,https://doi.org/10.1088/1126-6708/2008/04/063, arXiv:0802.1189.

[9] CMSCollaboration, The CMStrigger system,J. Instrum. 12 (2017) P01020, https://doi.org/10.1088/1748-0221/12/01/P01020,arXiv:1609.02366. [10] CMSCollaboration,TheCMSexperimentattheCERNLHC,J.Instrum.3(2008)

S08004,https://doi.org/10.1088/1748-0221/3/08/S08004.

[11] J.Alwall,M.Herquet,F.Maltoni,O.Mattelaer,T.Stelzer,MadGraph 5:going be-yond,J.HighEnergyPhys.06(2011)128,https://doi.org/10.1007/JHEP06(2011) 128,arXiv:1106.0522.

[12] T.Sjöstrand,S.Mrenna,P.Z.Skands,AbriefintroductiontoPYTHIA8.1, Com-put.Phys.Commun.178(2008)852,https://doi.org/10.1016/j.cpc.2008.01.036, arXiv:0710.3820.

[13] R.D.Ball,V.Bertone,S.Carrazza,C.S.Deans,L.DelDebbio,S.Forte,A.Guffanti, N.P.Hartland,J.I.Latorre,J.Rojo,M.Ubiali,NNPDF,Partondistributionswith LHCdata,Nucl. Phys. B867(2013) 244,https://doi.org/10.1016/j.nuclphysb. 2012.10.003,arXiv:1207.1303.

[14] S. Agostinelli, et al., GEANT4, GEANT4—a simulation toolkit, Nucl. Instrum. Methods, Sect. A 506 (2003) 250, https://doi.org/10.1016/S0168-9002(03) 01368-8.

[15] M.Strassler,K.Zurek,DiscoveringtheHiggsthroughhighly-displacedvertices, Phys.Lett.B263(2008)2,https://doi.org/10.1016/j.physletb.2008.02.008. [16] G.R.Farrar,P.Fayet,Phenomenologyoftheproduction,decay,anddetectionof

newhadronicstatesassociatedwithsupersymmetry,Phys.Lett.B76(1978) 575,https://doi.org/10.1016/0370-2693(78)90858-4.

[17] P.W.Graham,D.E.Kaplan,S.Rajendran,P.Saraswat,Displacedsupersymmetry, J.HighEnergyPhys.07(2012)149,https://doi.org/10.1007/JHEP07(2012)149, arXiv:1204.6038.

[18] CMSCollaboration,Descriptionandperformanceoftrackandprimary-vertex reconstructionwiththeCMStracker,J.Instrum.9(2014)P10009,https://doi. org/10.1088/1748-0221/9/10/P10009,arXiv:1405.6569.

[19] CMSCollaboration,JetPerformanceinppCollisionsat√s=7 TeV,CMSPhysics AnalysisSummary,CMS-PAS-JME-10–003,2010,http://cdsweb.cern.ch/record/ 1279362.

[20] T.Junk,Confidencelevelcomputationforcombiningsearcheswithsmall statis-tics,Nucl.Instrum.Methods,Sect.A434(1999)435,https://doi.org/10.1016/ S0168-9002(99)00498-2,arXiv:hep-ex/9902006.

[21] A.L.Read,Presentationofsearchresults:theC Ls technique,in:DurhamIPPP

Workshop:AdvancedStatisticalTechniquesinParticlePhysics,Durham, UK, 2002,p. 2693,J.Phys.G28(2002),https://doi.org/10.1088/0954-3899/28/10/ 313.

[22] T. L.H.C. G.,TheATLASCollaboration,TheCMSCollaboration,Procedurefor theLHCHiggsBosonSearchCombinationinSummer2011,TechnicalReport CMS-NOTE-2011-005.ATL-PHYS-PUB-2011-11,CERN,Geneva,2011,https://cds. cern.ch/record/1379837.

[23] G.Cowan,K.Cranmer,E.Gross,O.Vitells,Asymptoticformulaefor likelihood-basedtestsofnewphysics,Eur.Phys.J.C71(2011)1554,https://doi.org/10. 1140/epjc/s10052-011-1554-0, arXiv:1007.1727, Erratum: https://doi.org/10. 1140/epjc/s10052-013-2501-z.

[24] W.Beenakker,R.Höpker,M.Spira,P.M.Zerwas,Squarkandgluinoproduction athadroncolliders,Nucl.Phys.B492(1997)51,https://doi.org/10.1016/S0550 -3213(97)80027-2,arXiv:hep-ph/9610490.

[25]A. Kulesza, L. Motyka, Threshold resummation for squark–antisquark and gluino-pairproductionattheLHC,Phys.Rev.Lett.102(2009)111802,arXiv: 0807.2405.

[26]A.Kulesza,L.Motyka,Softgluonresummationfortheproductionofgluino– gluinoandsquark–antisquarkpairsattheLHC,Phys.Rev.D80(2009)095004, arXiv:0905.4749.

[27] W.Beenakker,S.Brensing,M.Krämer,A.Kulesza,E.Laenen,I.Niessen, Soft-gluon resummation for squark and gluino hadroproduction, J. HighEnergy Phys. 12 (2009) 041, https://doi.org/10.1088/1126-6708/2009/12/041, arXiv: 0909.4418.

[28] W. Beenakker, S. Brensing, M. Krämer, A. Kulesza, E. Laenen, L. Motyka, I. Niessen,Squarkandgluinohadroproduction,Int.J.Mod.Phys.A26(2011) 2637,https://doi.org/10.1142/S0217751X11053560,arXiv:1105.1110. [29] C. Borschensky, M. Krämer, A. Kulesza, M. Mangano, S. Padhi, T. Plehn,

X. Portell, Squark and gluino production cross sectionsin pp collisions at √

s=13,14,33 and100 TeV, Eur.Phys.J.C74(2014)3174,https://doi.org/ 10.1140/epjc/s10052-014-3174-y,arXiv:1407.5066.

TheCMSCollaboration

A.M. Sirunyan,A. Tumasyan

YerevanPhysicsInstitute,Yerevan,Armenia

W. Adam, F. Ambrogi, E. Asilar,T. Bergauer, J. Brandstetter, E. Brondolin, M. Dragicevic, J. Erö,M. Flechl,

M. Friedl,R. Frühwirth1,V.M. Ghete, J. Grossmann, J. Hrubec, M. Jeitler1, A. König,N. Krammer,

I. Krätschmer,D. Liko,T. Madlener, I. Mikulec, E. Pree,D. Rabady, N. Rad, H. Rohringer, J. Schieck1,

R. Schöfbeck, M. Spanring,D. Spitzbart, J. Strauss,W. Waltenberger, J. Wittmann, C.-E. Wulz1,M. Zarucki

InstitutfürHochenergiephysik,Wien,Austria

V. Chekhovsky, V. Mossolov,J. Suarez Gonzalez

InstituteforNuclearProblems,Minsk,Belarus

E.A. De Wolf,D. Di Croce, X. Janssen,J. Lauwers, M. Van De Klundert, H. Van Haevermaet,

P. Van Mechelen,N. Van Remortel

UniversiteitAntwerpen,Antwerpen,Belgium

S. Abu Zeid,F. Blekman, J. D’Hondt, I. De Bruyn, J. De Clercq, K. Deroover, G. Flouris, D. Lontkovskyi,

S. Lowette,S. Moortgat, L. Moreels,A. Olbrechts, Q. Python, K. Skovpen, S. Tavernier,W. Van Doninck,

P. Van Mulders,I. Van Parijs

VrijeUniversiteitBrussel,Brussel,Belgium

H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, G. Fasanella,L. Favart, R. Goldouzian, A. Grebenyuk,

G. Karapostoli,T. Lenzi,J. Luetic, T. Maerschalk, A. Marinov, A. Randle-conde,T. Seva, C. Vander Velde,

P. Vanlaer,D. Vannerom, R. Yonamine,F. Zenoni, F. Zhang2

UniversitéLibredeBruxelles,Bruxelles,Belgium

A. Cimmino,T. Cornelis, D. Dobur,A. Fagot, M. Gul, I. Khvastunov,D. Poyraz, C. Roskas, S. Salva,

M. Tytgat,W. Verbeke, N. Zaganidis

GhentUniversity,Ghent,Belgium

H. Bakhshiansohi,O. Bondu, S. Brochet,G. Bruno, A. Caudron, S. De Visscher, C. Delaere, M. Delcourt,

B. Francois,A. Giammanco, A. Jafari,M. Komm, G. Krintiras, V. Lemaitre,A. Magitteri, A. Mertens,

M. Musich, K. Piotrzkowski,L. Quertenmont,M. Vidal Marono, S. Wertz

UniversitéCatholiquedeLouvain,Louvain-la-Neuve,Belgium N. Beliy

W.L. Aldá Júnior, F.L. Alves,G.A. Alves, L. Brito,M. Correa Martins Junior,C. Hensel, A. Moraes,M.E. Pol, P. Rebello Teles

CentroBrasileirodePesquisasFisicas,RiodeJaneiro,Brazil

E. Belchior Batista Das Chagas, W. Carvalho,J. Chinellato3,A. Custódio, E.M. Da Costa, G.G. Da Silveira4,

D. De Jesus Damiao,S. Fonseca De Souza, L.M. Huertas Guativa, H. Malbouisson,M. Melo De Almeida,

C. Mora Herrera,L. Mundim, H. Nogima,A. Santoro, A. Sznajder,E.J. Tonelli Manganote3,

F. Torres Da Silva De Araujo,A. Vilela Pereira

UniversidadedoEstadodoRiodeJaneiro,RiodeJaneiro,Brazil

S. Ahujaa, C.A. Bernardesa, T.R. Fernandez Perez Tomeia, E.M. Gregoresb,P.G. Mercadanteb,

S.F. Novaesa, Sandra S. Padulaa, D. Romero Abadb,J.C. Ruiz Vargasa

a_{UniversidadeEstadualPaulista,SãoPaulo,Brazil} b_{UniversidadeFederaldoABC,SãoPaulo,Brazil}

A. Aleksandrov, R. Hadjiiska, P. Iaydjiev,M. Misheva, M. Rodozov, M. Shopova,S. Stoykova, G. Sultanov

InstituteforNuclearResearchandNuclearEnergy,BulgarianAcademyofSciences,Sofia,Bulgaria

A. Dimitrov, I. Glushkov,L. Litov, B. Pavlov,P. Petkov

UniversityofSofia,Sofia,Bulgaria

W. Fang5, X. Gao5

BeihangUniversity,Beijing,China

M. Ahmad, J.G. Bian, G.M. Chen, H.S. Chen,M. Chen, Y. Chen, C.H. Jiang, D. Leggat, H. Liao,Z. Liu,

F. Romeo,S.M. Shaheen, A. Spiezia, J. Tao, C. Wang,Z. Wang, E. Yazgan, H. Zhang, J. Zhao

InstituteofHighEnergyPhysics,Beijing,China

Y. Ban, G. Chen, Q. Li, S. Liu,Y. Mao, S.J. Qian, D. Wang,Z. Xu

StateKeyLaboratoryofNuclearPhysicsandTechnology,PekingUniversity,Beijing,China

C. Avila,A. Cabrera, L.F. Chaparro Sierra, C. Florez, C.F. González Hernández,J.D. Ruiz Alvarez

UniversidaddeLosAndes,Bogota,Colombia

B. Courbon, N. Godinovic, D. Lelas,I. Puljak, P.M. Ribeiro Cipriano, T. Sculac

UniversityofSplit,FacultyofElectricalEngineering,MechanicalEngineeringandNavalArchitecture,Split,Croatia

Z. Antunovic, M. Kovac

UniversityofSplit,FacultyofScience,Split,Croatia

V. Brigljevic,D. Ferencek, K. Kadija,B. Mesic, A. Starodumov6, T. Susa

InstituteRudjerBoskovic,Zagreb,Croatia

M.W. Ather,A. Attikis, G. Mavromanolakis, J. Mousa,C. Nicolaou, F. Ptochos, P.A. Razis, H. Rykaczewski

UniversityofCyprus,Nicosia,Cyprus

M. Finger7, M. Finger Jr.7

CharlesUniversity,Prague,CzechRepublic E. Carrera Jarrin

E. El-khateeb8,S. Elgammal9,A. Mohamed10

AcademyofScientificResearchandTechnologyoftheArabRepublicofEgypt,EgyptianNetworkofHighEnergyPhysics,Cairo,Egypt

R.K. Dewanjee,M. Kadastik, L. Perrini, M. Raidal, A. Tiko,C. Veelken

NationalInstituteofChemicalPhysicsandBiophysics,Tallinn,Estonia

P. Eerola,J. Pekkanen, M. Voutilainen

DepartmentofPhysics,UniversityofHelsinki,Helsinki,Finland

J. Härkönen,T. Järvinen, V. Karimäki,R. Kinnunen, T. Lampén, K. Lassila-Perini, S. Lehti,T. Lindén,

P. Luukka, E. Tuominen, J. Tuominiemi,E. Tuovinen

HelsinkiInstituteofPhysics,Helsinki,Finland

J. Talvitie,T. Tuuva

LappeenrantaUniversityofTechnology,Lappeenranta,Finland

M. Besancon,F. Couderc, M. Dejardin, D. Denegri,J.L. Faure, F. Ferri, S. Ganjour, S. Ghosh,A. Givernaud,

P. Gras, G. Hamel de Monchenault,P. Jarry, I. Kucher, E. Locci,M. Machet, J. Malcles, G. Negro,J. Rander,

A. Rosowsky,M.Ö. Sahin, M. Titov

IRFU,CEA,UniversitéParis-Saclay,Gif-sur-Yvette,France

A. Abdulsalam,I. Antropov, S. Baffioni, F. Beaudette, P. Busson, L. Cadamuro, C. Charlot,

R. Granier de Cassagnac,M. Jo, S. Lisniak,A. Lobanov, J. Martin Blanco, M. Nguyen, C. Ochando,

G. Ortona,P. Paganini, P. Pigard,S. Regnard, R. Salerno, J.B. Sauvan, Y. Sirois, A.G. Stahl Leiton, T. Strebler,

Y. Yilmaz,A. Zabi, A. Zghiche

LaboratoireLeprince-Ringuet,Ecolepolytechnique,CNRS/IN2P3,UniversitéParis-Saclay,Palaiseau,France

J.-L. Agram11,J. Andrea, D. Bloch,J.-M. Brom, M. Buttignol,E.C. Chabert, N. Chanon, C. Collard,

E. Conte11,X. Coubez, J.-C. Fontaine11, D. Gelé, U. Goerlach,M. Jansová, A.-C. Le Bihan, N. Tonon,

P. Van Hove

UniversitédeStrasbourg,CNRS,IPHCUMR7178,F-67000Strasbourg,France S. Gadrat

CentredeCalculdel’InstitutNationaldePhysiqueNucleaireetdePhysiquedesParticules,CNRS/IN2P3,Villeurbanne,France

S. Beauceron,C. Bernet, G. Boudoul,R. Chierici, D. Contardo, P. Depasse,H. El Mamouni, J. Fay, L. Finco,

S. Gascon,M. Gouzevitch, G. Grenier, B. Ille, F. Lagarde, I.B. Laktineh, M. Lethuillier,L. Mirabito,

A.L. Pequegnot, S. Perries,A. Popov12,V. Sordini, M. Vander Donckt, S. Viret

UniversitédeLyon,UniversitéClaudeBernardLyon1,CNRS-IN2P3,InstitutdePhysiqueNucléairedeLyon,Villeurbanne,France

T. Toriashvili13

GeorgianTechnicalUniversity,Tbilisi,Georgia

I. Bagaturia14

TbilisiStateUniversity,Tbilisi,Georgia

C. Autermann,S. Beranek, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, M. Preuten,C. Schomakers, J. Schulz,

T. Verlage

A. Albert, E. Dietz-Laursonn, D. Duchardt, M. Endres,M. Erdmann, S. Erdweg, T. Esch,R. Fischer, A. Güth,

M. Hamer,T. Hebbeker,C. Heidemann, K. Hoepfner,S. Knutzen, M. Merschmeyer,A. Meyer, P. Millet,

S. Mukherjee,M. Olschewski, K. Padeken, T. Pook,M. Radziej, H. Reithler, M. Rieger,F. Scheuch,

D. Teyssier,S. Thüer

RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

G. Flügge, B. Kargoll, T. Kress, A. Künsken, J. Lingemann, T. Müller,A. Nehrkorn, A. Nowack, C. Pistone,

O. Pooth,A. Stahl15

RWTHAachenUniversity,III.PhysikalischesInstitutB,Aachen,Germany

M. Aldaya Martin,T. Arndt, C. Asawatangtrakuldee, K. Beernaert,O. Behnke, U. Behrens,

A. Bermúdez Martínez, A.A. Bin Anuar, K. Borras16,V. Botta, A. Campbell, P. Connor,

C. Contreras-Campana, F. Costanza, C. Diez Pardos,G. Eckerlin, D. Eckstein, T. Eichhorn, E. Eren,

E. Gallo17,J. Garay Garcia, A. Geiser, A. Gizhko, J.M. Grados Luyando, A. Grohsjean, P. Gunnellini,

A. Harb,J. Hauk, M. Hempel18,H. Jung,A. Kalogeropoulos, M. Kasemann, J. Keaveney, C. Kleinwort,

I. Korol,D. Krücker, W. Lange, A. Lelek, T. Lenz,J. Leonard, K. Lipka,W. Lohmann18, R. Mankel,

I.-A. Melzer-Pellmann,A.B. Meyer, G. Mittag, J. Mnich, A. Mussgiller, E. Ntomari,D. Pitzl,R. Placakyte,

A. Raspereza,B. Roland, M. Savitskyi, P. Saxena,R. Shevchenko, S. Spannagel, N. Stefaniuk,

G.P. Van Onsem,R. Walsh, Y. Wen, K. Wichmann,C. Wissing, O. Zenaiev

DeutschesElektronen-Synchrotron,Hamburg,Germany

S. Bein,V. Blobel, M. Centis Vignali, A.R. Draeger, T. Dreyer, E. Garutti,D. Gonzalez, J. Haller,

A. Hinzmann, M. Hoffmann,A. Karavdina, R. Klanner, R. Kogler, N. Kovalchuk,S. Kurz, T. Lapsien,

I. Marchesini, D. Marconi,M. Meyer, M. Niedziela, D. Nowatschin, F. Pantaleo15,T. Peiffer, A. Perieanu,

C. Scharf, P. Schleper, A. Schmidt, S. Schumann,J. Schwandt,J. Sonneveld, H. Stadie,G. Steinbrück,

F.M. Stober,M. Stöver, H. Tholen, D. Troendle,E. Usai, L. Vanelderen,A. Vanhoefer, B. Vormwald

UniversityofHamburg,Hamburg,Germany

M. Akbiyik, C. Barth,S. Baur, E. Butz, R. Caspart, T. Chwalek, F. Colombo, W. De Boer,A. Dierlamm,

B. Freund, R. Friese,M. Giffels, A. Gilbert, D. Haitz,F. Hartmann15,S.M. Heindl, U. Husemann, F. Kassel15,

S. Kudella, H. Mildner, M.U. Mozer,Th. Müller, M. Plagge, G. Quast, K. Rabbertz, M. Schröder,I. Shvetsov,

G. Sieber, H.J. Simonis,R. Ulrich, S. Wayand, M. Weber, T. Weiler, S. Williamson,C. Wöhrmann, R. Wolf

InstitutfürExperimentelleKernphysik,Karlsruhe,Germany

G. Anagnostou, G. Daskalakis,T. Geralis,V.A. Giakoumopoulou, A. Kyriakis, D. Loukas, I. Topsis-Giotis

InstituteofNuclearandParticlePhysics(INPP),NCSRDemokritos,AghiaParaskevi,Greece

S. Kesisoglou, A. Panagiotou, N. Saoulidou

NationalandKapodistrianUniversityofAthens,Athens,Greece

I. Evangelou, C. Foudas,P. Kokkas, S. Mallios, N. Manthos, I. Papadopoulos,E. Paradas, J. Strologas,

F.A. Triantis

UniversityofIoánnina,Ioánnina,Greece

M. Csanad, N. Filipovic,G. Pasztor

MTA-ELTELendületCMSParticleandNuclearPhysicsGroup,EötvösLorándUniversity,Budapest,Hungary

G. Bencze,C. Hajdu, D. Horvath19,Á. Hunyadi, F. Sikler,V. Veszpremi, G. Vesztergombi20,A.J. Zsigmond

N. Beni,S. Czellar, J. Karancsi21,A. Makovec,J. Molnar, Z. Szillasi InstituteofNuclearResearchATOMKI,Debrecen,Hungary

M. Bartók20, P. Raics, Z.L. Trocsanyi, B. Ujvari

InstituteofPhysics,UniversityofDebrecen,Debrecen,Hungary

S. Choudhury,J.R. Komaragiri

IndianInstituteofScience(IISc),Bangalore,India

S. Bahinipati22,S. Bhowmik, P. Mal, K. Mandal, A. Nayak23, D.K. Sahoo22, N. Sahoo,S.K. Swain

NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

S. Bansal,S.B. Beri, V. Bhatnagar, U. Bhawandeep, R. Chawla, N. Dhingra, A.K. Kalsi,A. Kaur, M. Kaur,

R. Kumar,P. Kumari, A. Mehta,J.B. Singh, G. Walia

PanjabUniversity,Chandigarh,India

Ashok Kumar,Aashaq Shah, A. Bhardwaj, S. Chauhan,B.C. Choudhary, R.B. Garg,S. Keshri, A. Kumar,

S. Malhotra,M. Naimuddin, K. Ranjan,R. Sharma, V. Sharma

UniversityofDelhi,Delhi,India

R. Bhardwaj,R. Bhattacharya,S. Bhattacharya, S. Dey,S. Dutt, S. Dutta,S. Ghosh, N. Majumdar, A. Modak,

K. Mondal, S. Mukhopadhyay, S. Nandan,A. Purohit, A. Roy, D. Roy, S. Roy Chowdhury, S. Sarkar,

M. Sharan, S. Thakur

SahaInstituteofNuclearPhysics,HBNI,Kolkata,India P.K. Behera

IndianInstituteofTechnologyMadras,Madras,India

R. Chudasama,D. Dutta, V. Jha, V. Kumar, A.K. Mohanty15, P.K. Netrakanti,L.M. Pant, P. Shukla,A. Topkar

BhabhaAtomicResearchCentre,Mumbai,India

T. Aziz,S. Dugad, B. Mahakud, S. Mitra, G.B. Mohanty, B. Parida,N. Sur, B. Sutar

TataInstituteofFundamentalResearch-A,Mumbai,India

S. Banerjee, S. Bhattacharya, S. Chatterjee,P. Das, M. Guchait,Sa. Jain, S. Kumar, M. Maity24,

G. Majumder,K. Mazumdar, T. Sarkar24, N. Wickramage25

TataInstituteofFundamentalResearch-B,Mumbai,India

S. Chauhan,S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, S. Sharma

IndianInstituteofScienceEducationandResearch(IISER),Pune,India

S. Chenarani26, E. Eskandari Tadavani,S.M. Etesami26, M. Khakzad, M. Mohammadi Najafabadi,

M. Naseri, S. Paktinat Mehdiabadi27,F. Rezaei Hosseinabadi, B. Safarzadeh28,M. Zeinali

InstituteforResearchinFundamentalSciences(IPM),Tehran,Iran

M. Felcini,M. Grunewald

UniversityCollegeDublin,Dublin,Ireland

M. Abbresciaa,b, C. Calabriaa,b, C. Caputoa,b, A. Colaleoa,D. Creanzaa,c, L. Cristellaa,b,N. De Filippisa,c, M. De Palmaa,b, F. Erricoa,b,L. Fiorea,G. Iasellia,c,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,b, A. Ranieria,G. Selvaggia,b, A. Sharmaa,L. Silvestrisa,15, R. Vendittia,P. Verwilligena

a_{INFNSezionediBari,Bari,Italy} b_{UniversitàdiBari,Bari,Italy} c_{PolitecnicodiBari,Bari,Italy}

G. Abbiendia,C. Battilanaa,b,D. Bonacorsia,b,S. Braibant-Giacomellia,b, R. Campaninia,b, P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa,S.S. Chhibraa, G. Codispotia,b, M. Cuffiania,b,G.M. Dallavallea,F. Fabbria, A. Fanfania,b, D. Fasanellaa,b,P. Giacomellia,C. Grandia,L. Guiduccia,b, S. Marcellinia, G. Masettia, A. Montanaria, F.L. Navarriaa,b, A. Perrottaa, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b,N. Tosia a_{INFNSezionediBologna,Bologna,Italy}

b_{UniversitàdiBologna,Bologna,Italy}

S. Albergoa,b,S. Costaa,b,A. Di Mattiaa,F. Giordanoa,b,R. Potenzaa,b,A. Tricomia,b,C. Tuvea,b a_{INFNSezionediCatania,Catania,Italy}

b_{UniversitàdiCatania,Catania,Italy}

G. Barbaglia, K. Chatterjeea,b,V. Ciullia,b,C. Civininia, R. D’Alessandroa,b, E. Focardia,b,P. Lenzia,b, M. Meschinia, S. Paolettia,L. Russoa,29, G. Sguazzonia, D. Stroma, L. Viliania,b,15

a_{INFNSezionediFirenze,Firenze,Italy} b_{UniversitàdiFirenze,Firenze,Italy}

L. Benussi, S. Bianco, F. Fabbri,D. Piccolo, F. Primavera15

INFNLaboratoriNazionalidiFrascati,Frascati,Italy

V. Calvellia,b, F. Ferroa, E. Robuttia,S. Tosia,b a_{INFNSezionediGenova,Genova,Italy}

b_{UniversitàdiGenova,Genova,Italy}

L. Brianzaa,b, F. Brivioa,b, V. Cirioloa,b, M.E. Dinardoa,b,S. Fiorendia,b, S. Gennaia, A. Ghezzia,b, P. Govonia,b_{,M. Malberti}a,b_{, S. Malvezzi}a_{, R.A. Manzoni}a,b_{,D. Menasce}a_{,L. Moroni}a_{,M. Paganoni}a,b_,

K. Pauwelsa,b,D. Pedrinia, S. Pigazzinia,b,30, S. Ragazzia,b, T. Tabarelli de Fatisa,b a_{INFNSezionediMilano-Bicocca,Milano,Italy}

b_{UniversitàdiMilano-Bicocca,Milano,Italy}

S. Buontempoa, N. Cavalloa,c, S. Di Guidaa,d,15, F. Fabozzia,c,F. Fiengaa,b, A.O.M. Iorioa,b, W.A. Khana, L. Listaa,S. Meolaa,d,15,P. Paoluccia,15,C. Sciaccaa,b,F. Thyssena

a_{INFNSezionediNapoli,Napoli,Italy} b_{UniversitàdiNapoli‘FedericoII’,Napoli,Italy} c_{UniversitàdellaBasilicata,Potenza,Italy} d_{UniversitàG.Marconi,Roma,Italy}

P. Azzia,15, N. Bacchettaa, L. Benatoa,b,D. Biselloa,b, A. Bolettia,b,R. Carlina,b,

A. Carvalho Antunes De Oliveiraa,b, P. Checchiaa,M. Dall’Ossoa,b,P. De Castro Manzanoa,T. Dorigoa,

U. Gasparinia,b,S. Lacapraraa,M. Margonia,b,A.T. Meneguzzoa,b, M. Pegoraroa,N. Pozzobona,b,

P. Ronchesea,b,R. Rossina,b,M. Sgaravattoa,F. Simonettoa,b,E. Torassaa, S. Venturaa,M. Zanettia,b, P. Zottoa,b, G. Zumerlea,b

a_{INFNSezionediPadova,Padova,Italy} b_{UniversitàdiPadova,Padova,Italy} c_{UniversitàdiTrento,Trento,Italy}

A. Braghieria,F. Fallavollitaa,b, A. Magnania,b, P. Montagnaa,b,S.P. Rattia,b, V. Rea, M. Ressegotti, C. Riccardia,b,P. Salvinia,I. Vaia,b, P. Vituloa,b

a_{INFNSezionediPavia,Pavia,Italy} b_{UniversitàdiPavia,Pavia,Italy}

L. Alunni Solestizia,b, 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

a_{INFNSezionediPerugia,Perugia,Italy} b_{UniversitàdiPerugia,Perugia,Italy}

K. Androsova, P. Azzurria,15,G. Bagliesia,J. Bernardinia,T. Boccalia,L. Borrello, R. Castaldia, M.A. Cioccia,b,R. Dell’Orsoa, G. Fedia,L. Gianninia,c, A. Giassia,M.T. Grippoa,29,F. Ligabuea,c, T. Lomtadzea, E. Mancaa,c, G. Mandorlia,c, L. Martinia,b, A. Messineoa,b, F. Pallaa,A. Rizzia,b,

A. Savoy-Navarroa,31,P. Spagnoloa,R. Tenchinia,G. Tonellia,b,A. Venturia,P.G. Verdinia

a_{INFNSezionediPisa,Pisa,Italy} b_{UniversitàdiPisa,Pisa,Italy}

c_{ScuolaNormaleSuperiorediPisa,Pisa,Italy}

L. Baronea,b, F. Cavallaria,M. Cipriania,b, N. Dacia,D. Del Rea,b,15,M. Diemoza,S. Gellia,b,E. Longoa,b, F. Margarolia,b, B. Marzocchia,b,P. Meridiania, G. Organtinia,b,R. Paramattia,b,F. Preiatoa,b,

S. Rahatloua,b,C. Rovellia, F. Santanastasioa,b a_{INFNSezionediRoma,Rome,Italy}

b_{SapienzaUniversitàdiRoma,Rome,Italy}

N. Amapanea,b,R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c,N. Bartosika,R. Bellana,b,C. Biinoa, N. Cartigliaa,F. Cennaa,b, M. Costaa,b,R. Covarellia,b,A. Deganoa,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,F. Raveraa,b,A. Romeroa,b, M. Ruspaa,c, R. Sacchia,b, K. Shchelinaa,b, V. Solaa,A. Solanoa,b,A. Staianoa,P. Traczyka,b

a_{INFNSezionediTorino,Torino,Italy} b_{UniversitàdiTorino,Torino,Italy}

c_{UniversitàdelPiemonteOrientale,Novara,Italy}

S. Belfortea,M. Casarsaa, F. Cossuttia,G. Della Riccaa,b, A. Zanettia a_{INFNSezionediTrieste,Trieste,Italy}

b_{UniversitàdiTrieste,Trieste,Italy}

D.H. Kim,G.N. Kim, M.S. Kim, J. Lee,S. Lee, S.W. Lee, C.S. Moon, Y.D. Oh, S. Sekmen,D.C. Son,Y.C. Yang

KyungpookNationalUniversity,Daegu,RepublicofKorea A. Lee

ChonbukNationalUniversity,Jeonju,RepublicofKorea

H. Kim,D.H. Moon,G. Oh

ChonnamNationalUniversity,InstituteforUniverseandElementaryParticles,Kwangju,RepublicofKorea

J.A. Brochero Cifuentes,J. Goh, T.J. Kim

HanyangUniversity,Seoul,RepublicofKorea

S. Cho,S. Choi, Y. Go,D. Gyun, S. Ha,B. Hong, Y. Jo, Y. Kim, K. Lee,K.S. Lee,S. Lee,J. Lim, S.K. Park, Y. Roh

KoreaUniversity,Seoul,RepublicofKorea

J. Almond,J. Kim, J.S. Kim, H. Lee,K. Lee, K. Nam,S.B. Oh, B.C. Radburn-Smith, S.h. Seo, U.K. Yang,

H.D. Yoo,G.B. Yu

M. Choi,H. Kim, J.H. Kim, J.S.H. Lee, I.C. Park, G. Ryu UniversityofSeoul,Seoul,RepublicofKorea

Y. Choi,C. Hwang, J. Lee, I. Yu

SungkyunkwanUniversity,Suwon,RepublicofKorea

V. Dudenas, A. Juodagalvis,J. Vaitkus

VilniusUniversity,Vilnius,Lithuania

I. Ahmed,Z.A. Ibrahim, M.A.B. Md Ali32,F. Mohamad Idris33,W.A.T. Wan Abdullah, M.N. Yusli,

Z. Zolkapli

NationalCentreforParticlePhysics,UniversitiMalaya,KualaLumpur,Malaysia

H. Castilla-Valdez, E. De La Cruz-Burelo,I. Heredia-De La Cruz34,R. Lopez-Fernandez, J. Mejia Guisao,

A. Sanchez-Hernandez

CentrodeInvestigacionydeEstudiosAvanzadosdelIPN,MexicoCity,Mexico

S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia

UniversidadIberoamericana,MexicoCity,Mexico

I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada

BenemeritaUniversidadAutonomadePuebla,Puebla,Mexico A. Morelos Pineda

UniversidadAutónomadeSanLuisPotosí,SanLuisPotosí,Mexico D. Krofcheck

UniversityofAuckland,Auckland,NewZealand P.H. Butler

UniversityofCanterbury,Christchurch,NewZealand

A. Ahmad, M. Ahmad, Q. Hassan,H.R. Hoorani, A. Saddique, M.A. Shah, M. Shoaib, M. Waqas

NationalCentreforPhysics,Quaid-I-AzamUniversity,Islamabad,Pakistan

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

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

NationalCentreforNuclearResearch,Swierk,Poland

K. Bunkowski,A. Byszuk35, K. Doroba,A. Kalinowski, M. Konecki,J. Krolikowski, M. Misiura,

M. Olszewski, A. Pyskir,M. Walczak

InstituteofExperimentalPhysics,FacultyofPhysics,UniversityofWarsaw,Warsaw,Poland

P. Bargassa,C. Beirão Da Cruz E Silva, B. Calpas, A. Di Francesco, P. Faccioli,M. Gallinaro, J. Hollar,

N. Leonardo,L. Lloret Iglesias,M.V. Nemallapudi, J. Seixas,O. Toldaiev, D. Vadruccio, J. Varela

LaboratóriodeInstrumentaçãoeFísicaExperimentaldePartículas,Lisboa,Portugal

V. Alexakhin,A. Golunov, I. Golutvin, N. Gorbounov, I. Gorbunov, A. Kamenev, V. Karjavin, A. Lanev,

A. Malakhov,V. Matveev36,37,V. Palichik, V. Perelygin, M. Savina, S. Shmatov, S. Shulha,N. Skatchkov,

V. Smirnov, A. Zarubin

Y. Ivanov,V. Kim38,E. Kuznetsova39, P. Levchenko,V. Murzin, V. Oreshkin, I. Smirnov, V. Sulimov,

L. Uvarov, S. Vavilov, A. Vorobyev

PetersburgNuclearPhysicsInstitute,Gatchina(St.Petersburg),Russia

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

A. Pashenkov,D. Tlisov, A. Toropin

InstituteforNuclearResearch,Moscow,Russia

V. Epshteyn,V. Gavrilov, N. Lychkovskaya,V. Popov, I. Pozdnyakov,G. Safronov, A. Spiridonov,

A. Stepennov, M. Toms,E. Vlasov, A. Zhokin

InstituteforTheoreticalandExperimentalPhysics,Moscow,Russia

T. Aushev,A. Bylinkin37

MoscowInstituteofPhysicsandTechnology,Moscow,Russia

R. Chistov40, M. Danilov40,P. Parygin,D. Philippov, S. Polikarpov,E. Tarkovskii

NationalResearchNuclearUniversity‘MoscowEngineeringPhysicsInstitute’(MEPhI),Moscow,Russia

V. Andreev,M. Azarkin37,I. Dremin37, M. Kirakosyan37,A. Terkulov

P.N.LebedevPhysicalInstitute,Moscow,Russia

A. Baskakov,A. Belyaev, E. Boos,M. Dubinin41,L. Dudko, A. Ershov, A. Gribushin, V. Klyukhin,

O. Kodolova,I. Lokhtin,I. Miagkov, S. Obraztsov, S. Petrushanko,V. Savrin, A. Snigirev

SkobeltsynInstituteofNuclearPhysics,LomonosovMoscowStateUniversity,Moscow,Russia

V. Blinov42, Y. Skovpen42,D. Shtol42

NovosibirskStateUniversity(NSU),Novosibirsk,Russia

I. Azhgirey,I. Bayshev,S. Bitioukov, D. Elumakhov, V. Kachanov, A. Kalinin, D. Konstantinov,

V. Krychkine, V. Petrov, R. Ryutin, A. Sobol,S. Troshin, N. Tyurin,A. Uzunian, A. Volkov

StateResearchCenterofRussianFederation,InstituteforHighEnergyPhysics,Protvino,Russia

P. Adzic43,P. Cirkovic, D. Devetak,M. Dordevic, J. Milosevic,V. Rekovic

UniversityofBelgrade,FacultyofPhysicsandVincaInstituteofNuclearSciences,Belgrade,Serbia

J. Alcaraz Maestre,M. Barrio Luna, M. Cerrada,N. Colino, B. De La Cruz,A. Delgado Peris,

A. Escalante Del Valle,C. Fernandez Bedoya, J.P. Fernández Ramos,J. Flix, M.C. Fouz,P. Garcia-Abia,

O. Gonzalez Lopez,S. Goy Lopez, J.M. Hernandez, M.I. Josa, A. Pérez-Calero Yzquierdo, J. Puerta Pelayo,

A. Quintario Olmeda,I. Redondo, L. Romero,M.S. Soares, A. Álvarez Fernández

CentrodeInvestigacionesEnergéticasMedioambientalesyTecnológicas(CIEMAT),Madrid,Spain

C. Albajar, J.F. de Trocóniz,M. Missiroli, D. Moran

UniversidadAutónomadeMadrid,Madrid,Spain

J. Cuevas,C. Erice, J. Fernandez Menendez, I. Gonzalez Caballero,J.R. González Fernández,

E. Palencia Cortezon,S. Sanchez Cruz, I. Suárez Andrés,P. Vischia, J.M. Vizan Garcia

UniversidaddeOviedo,Oviedo,Spain

I.J. Cabrillo, A. Calderon, B. Chazin Quero,E. Curras, M. Fernandez,J. Garcia-Ferrero, G. Gomez,

T. Rodrigo,A. Ruiz-Jimeno,L. Scodellaro, N. Trevisani,I. Vila, R. Vilar Cortabitarte InstitutodeFísicadeCantabria(IFCA),CSIC-UniversidaddeCantabria,Santander,Spain

D. Abbaneo, E. Auffray, P. Baillon, A.H. Ball, D. Barney, M. Bianco,P. Bloch, A. Bocci, C. Botta,

T. Camporesi, R. Castello, M. Cepeda, G. Cerminara, E. Chapon, Y. Chen, D. d’Enterria, A. Dabrowski,

V. Daponte, A. David, M. De Gruttola, A. De Roeck, E. Di Marco44, M. Dobson, B. Dorney,T. du Pree,

M. Dünser,N. Dupont, A. Elliott-Peisert,P. Everaerts, G. Franzoni, J. Fulcher,W. Funk, D. Gigi,K. Gill,

F. Glege, D. Gulhan, S. Gundacker, M. Guthoff, P. Harris,J. Hegeman, V. Innocente, P. Janot,

O. Karacheban18,J. Kieseler, H. Kirschenmann, V. Knünz,A. Kornmayer15,M.J. Kortelainen,

M. Krammer1,C. Lange, P. Lecoq, C. Lourenço,M.T. Lucchini,L. Malgeri, M. Mannelli,A. Martelli,

F. Meijers, J.A. Merlin, S. Mersi, E. Meschi,P. Milenovic45,F. Moortgat, M. Mulders, H. Neugebauer,

S. Orfanelli,L. Orsini, L. Pape, E. Perez,M. Peruzzi, A. Petrilli, G. Petrucciani,A. Pfeiffer, M. Pierini,

A. Racz,T. Reis, G. Rolandi46,M. Rovere, H. Sakulin,C. Schäfer, C. Schwick,M. Seidel, M. Selvaggi,

A. Sharma,P. Silva, P. Sphicas47, J. Steggemann,M. Stoye, M. Tosi,D. Treille, A. Triossi,A. Tsirou,

V. Veckalns48, G.I. Veres20,M. Verweij, N. Wardle, W.D. Zeuner

CERN,EuropeanOrganizationforNuclearResearch,Geneva,Switzerland

W. Bertl†, L. Caminada49, K. Deiters,W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski,

U. Langenegger, T. Rohe, S.A. Wiederkehr

PaulScherrerInstitut,Villigen,Switzerland

F. Bachmair, L. Bäni, P. Berger, L. Bianchini, B. Casal, G. Dissertori,M. Dittmar, M. Donegà, C. Grab,

C. Heidegger, D. Hits, J. Hoss,G. Kasieczka, T. Klijnsma,W. Lustermann,B. Mangano, M. Marionneau,

M.T. Meinhard,D. Meister, F. Micheli,P. Musella, F. Nessi-Tedaldi, F. Pandolfi, J. Pata, F. Pauss,G. Perrin,

L. Perrozzi,M. Quittnat, M. Schönenberger, L. Shchutska, V.R. Tavolaro, K. Theofilatos,

M.L. Vesterbacka Olsson, R. Wallny, A. Zagozdzinska35,D.H. Zhu

ETHZurich–InstituteforParticlePhysicsandAstrophysics(IPA),Zurich,Switzerland

T.K. Aarrestad, C. Amsler50, M.F. Canelli,A. De Cosa, S. Donato, C. Galloni, T. Hreus, B. Kilminster,

J. Ngadiuba,D. Pinna, G. Rauco, P. Robmann, D. Salerno, C. Seitz,A. Zucchetta

UniversitätZürich,Zurich,Switzerland

V. Candelise,T.H. Doan, Sh. Jain,R. Khurana, C.M. Kuo,W. Lin, A. Pozdnyakov,S.S. Yu

NationalCentralUniversity,Chung-Li,Taiwan

Arun Kumar, P. Chang, Y. Chao, K.F. Chen, P.H. Chen, F. Fiori, W.-S. Hou,Y. Hsiung, Y.F. Liu,R.-S. Lu,

M. Miñano Moya,E. Paganis, A. Psallidas, J.f. Tsai

NationalTaiwanUniversity(NTU),Taipei,Taiwan

B. Asavapibhop, K. Kovitanggoon, G. Singh, N. Srimanobhas

ChulalongkornUniversity,FacultyofScience,DepartmentofPhysics,Bangkok,Thailand

A. Adiguzel51, F. Boran,S. Cerci52, S. Damarseckin, Z.S. Demiroglu, C. Dozen, I. Dumanoglu, S. Girgis,

G. Gokbulut, Y. Guler, I. Hos53, E.E. Kangal54, O. Kara, U. Kiminsu,M. Oglakci, G. Onengut55,

K. Ozdemir56, D. Sunar Cerci52, B. Tali52, H. Topakli57, S. Turkcapar,I.S. Zorbakir, C. Zorbilmez

ÇukurovaUniversity,PhysicsDepartment,ScienceandArtFaculty,Adana,Turkey

B. Bilin, G. Karapinar58, K. Ocalan59,M. Yalvac, M. Zeyrek