Search for heavy gauge W ' bosons in events with an energetic lepton and large missing transverse momentum at root s=13TeV

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Physics

Letters

B

www.elsevier.com/locate/physletb

Search

for

heavy

gauge

W



bosons

in

events

with

an

energetic

lepton

and

large

missing

transverse

momentum

at

√

s

=

13 TeV

.The CMS Collaboration CERN,Switzerland

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

Articlehistory:

Received29December2016

Receivedinrevisedform26March2017 Accepted20April2017

Availableonline25April2017 Editor:M.Doser Keywords: CMS Physics Exo BSMsearches W

A searchispresented forW bosonsineventswithanelectronormuonand largemissing transverse

momentum,usingproton–protoncollisiondataat√s=13 TeV collectedwiththeCMSdetectorin2015

andcorrespondingtoanintegratedluminosityof2.3 fb−1_{.Noevidenceofanexcessofeventsrelativeto}

thestandardmodelexpectationsisobserved.ForaWbosondescribedbythesequentialstandardmodel,

upperlimitsat95%confidencelevelaresetontheproductoftheproductioncrosssectionandbranching

fraction and lowerlimits areestablished onthe newbosonmass.Massesbelow4.1 TeV areexcluded

combiningelectronandmuondecaychannels,significantlyimprovingupontheresultsobtainedwiththe

8 TeVdata.Exclusionlimitsat95%confidencelevelontheproductoftheW productioncrosssection

andbranchingfractionarealsoderivedincombinationwiththe8 TeVdata.Finally,exclusionlimitsare

set for theproductionofgeneric W bosonsdecaying intothisfinalstateusingamodel-independent

approach.

©2017TheAuthor.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense

(http://creativecommons.org/licenses/by/4.0/).FundedbySCOAP3_.

1. Introduction

Manystandardmodel(SM)extensionsrequireadditionalheavy gauge bosons. Inparticular, the sequentialstandard model (SSM) [1]predictstheexistence ofanewmassiveboson,W,exhibiting thesamecouplingsastheSMWboson,i.e.,withfinalstates con-sistingeitherofachargedlepton andneutrinoora quarkpair. If sufficientlymassive,thedecaychannelW→tb isalsoallowed.

ThisLetterdescribesa searchfordeviationsfromthe SM pre-dictionsin eventswith a chargedlepton (electronor muon)and missing transverse momentum in the final state, proceeding as shown in Fig. 1. It is assumed that there is no interference be-tween the production ofthe new particle andthe production of theSM W boson.This wouldbe thecase, forexample,iftheW interactsvia V + A coupling.Its decaysto SM bosons (W, Z,H), whicharemodeldependent,areneglected.Dedicatedsearchesfor WdecaysintobosonscanbefoundinRefs.[2–4].

Similar searches havebeen carriedout by experiments at the FNAL Tevatron[5,6].The moststringentlimitsonthemass ofan SSMWbosontodatecomefromtheCERNLHCexperiments. Us-ing an integrated luminosity of 19.7 fb−1 of proton–proton (pp) collisions at a center-of-mass energy of 8 TeV, CMS set a lower limit at 95% confidence level (CL) on the W boson mass of

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

Fig. 1. ProductionanddecayofanSSMW boson.Thefinalstateshowndenotes boththe(ν)stateanditschargeconjugate.

3.22 TeVintheelectronchanneland2.99 TeVinthemuon chan-nel [7]. Combining both channelsresulted in an exclusion of W bosonswithamasslessthan3.28 TeV.Similarly,forthecombined channels at√s=8 TeV, ATLAS excluded W bosons withmasses lessthan3.24 TeV[8].

Because of the increase in the center-of-mass energy from 8 to13 TeV,thepartonluminositiesassociatedwithqqinteractions producingtheW bosonsincreasebymorethananorderof mag-nitudeinthehigh-mass region.LimitsderivedbyATLAS [9]using 3.2 fb−1 ofpp collisions at√s=13 TeV exclude SSMW bosons withmasseslessthan 4.07 TeV, forthecombinationof the elec-tronandmuondecaychannels.

The results presented inthis Letter are based onthe analysis of 2.3 fb−1 of pp collision datacollected with the CMSdetector during 2015, at √s=13 TeV. Limits are givenboth forthe SSM interpretation, and for a generic W, enabling constraints to be placedonavarietyofothermodels.

http://dx.doi.org/10.1016/j.physletb.2017.04.043

0370-2693/©2017TheAuthor.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).Fundedby SCOAP3_.

2. The CMS detector

A detailed description of the CMS detector and the coordi-nate system used can be found in Ref. [10]. The central feature of the CMS apparatus is a superconducting solenoid of 6 m in-ternal diameter, providing a magnetic field of 3.8 T. Within the solenoid volume are located the silicon pixel and strip tracker, measuring charged-particle trajectories in the pseudorapidity re-gion |η|<2.5, and the barrel and two endcap sections of the calorimeters (|η|<3): a lead tungstate crystal electromagnetic calorimeter(ECAL), anda brass andscintillator hadron calorime-ter(HCAL).Forwardcalorimetersextendthe η coverage provided bythebarrelandendcapdetectors(3<|η|<5).Muonsare mea-suredingas-ionizationdetectorsembeddedinthesteelflux-return yokeoutside the solenoid, inthe range |η|<2.4, withdetection planes made using three technologies: drift tubes, cathode strip chambers, andresistive platechambers. Additional detectorsand upgradedelectronics,installedbeforethebeginningofthe13 TeV datacollectionperiodin2015, haveyieldedimproved reconstruc-tionperformance formuons relativeto the 8 TeVdatacollection periodin2012.

TheCMSexperimenthasatwo-leveltriggersystem.Thelevel-1 (L1) trigger [11], composed of custom hardware processors, se-lects events of interest using information from the calorimeters andmuondetectorsandreducesthereadoutratefromthe40 MHz bunch-crossingfrequencytoamaximumof100 kHz.Thesoftware basedhigh-leveltrigger(HLT)[12]usesthefulleventinformation, includingthatfromtheinner tracker,toreduce theeventrateto the1 kHzthatisrecorded.

3. Analysis strategy and simulated samples

Theanalysisselects eventswitha high-energy chargedlepton andlarge missingtransverse momentum (pmiss

T ), which may in-dicate the presence of a non-interacting particle (neutrino). The quantity p_Tmiss isdefinedas−pT ofallreconstructed particles withEmiss_T beingthemagnitudeof p_Tmiss.

Themaindiscriminatingvariableusedinthesearchisthe trans-verse mass defined as MT=



2p_TEmiss_T (1−cos[φ(p_T,p_Tmiss)]), wherep

Tistheleptontransversemomentum, pTisitsmagnitude, and φ (p

T,pTmiss) is the difference in azimuthal angle between theleptontransversemomentumandmissingtransverse momen-tumvectors. Asignal fromverymassiveWbosons wouldappear athigh MTvalues.

The dominant and irreducible background is W → ν with

=e, μ, τ.TheW→τ ν processmostly contributestotheregion oflower MT valuesrelativeto decaysintotheother lepton chan-nels,becauseofthemomenta carriedaway bythetwo neutrinos fromthetaudecay.Possible interferencebetweentheproduction ofWandSM Wbosonsisnotconsidered.Theexistanceof inter-ferenceeffectswouldchangethetotalcrosssectionandtheshape ofthe MTspectrum[7].OtherbackgroundprocessesareDrell–Yan (where one of theleptons is not reconstructed), tt (semileptonic and dileptonic decay channels), single top quark, and dibosons (mainlyWW production).The contributionsfromtheseprocesses areestimatedfromsimulation.

Toestimate the dominant SM W boson background,different W→ ν samplesareused: aninclusiveonegeneratedat next-to-leading order (NLO) with MadGraph 5_amc@nlo [13] describing theeventswithaWbosonmassupto200 GeV,andseveral exclu-sivesamples,coveringthebosonhigh-massregion(from200 GeV onwards), generated at leading order (LO) with pythia 8.2 [14], tune CUETP8M1 [15,16],and NNPDF3.0parton distribution func-tions(PDF)[17].Amass-dependent K factor, toaccountforhigher

ordereffects,iscalculatedusing fewz 3.1[18] at next-to-next-to-leadingorder(NNLO)QCDprecision and mcsanc 1.01[19] atNLO electroweakprecision.Theapplicationofthe K factor improvesthe description ofthetailof the MT distribution,thekey element in thissearch.

High mass Drell–Yan and tt samples are generated with powheg(v2) [20–24], an event generator at NLO, with parton showering and hadronization described by pythia 8.2, using the CUETP8M1 tune and NNPDF3.0 PDF set. The tt category includes both semileptonic and dileptonic decay modes sam-ples. Single top quark production is generated inclusively with powheg_{(v2) in the tW-channel and with MadGraph5_aMC@NLO} matched to pythia8.2 using the FXFX algorithm [25], in the

s-and t-channels. Diboson (WW, WZ, andZZ) productionis gener-ated with pythia 8.2, tune CUETP8M1, andthe NNPDF2.3LO PDF set[26].

Backgroundfromjetsmisidentified aselectrons (referredtoas QCD multijet background in what follows) is largely rejected by theanalysisselectioncriteriadescribedinthenextsection,andthe residualcontributionisestimatedfromdatabyusingacontrol re-giondefinedby theelectronisolation andtheratio p

T/E miss T .This method ofestimating the QCD multijet contributionwas already usedinourpreviousanalysis[7]andisbasedonfourregions (iso-latedandnon-isolated signalandbackgroundevents) toestimate the normalizationandprovidethe templatedata.The probability tomisidentifyjetsasmuonsisnegligible.

For the signal events, the generation of SSM W→ ν sam-plesfortheelectronandmuon decaychannelsisperformedwith pythia8.2atLO,tuneCUETP8M1,andtheNNPDF3.0PDFset.A W mass-dependent K factor is applied based on NNLO QCD cross sections as calculated with fewz 3.1. The K factor varies from 1.3 to 1.1 for the range of W masses studied in this analysis, namelyfrom0.4to 5.8 TeV.The NNLO correctionsdecreasewith W boson masses up to around 4.5 TeV. For higher W masses, the phase space for production in pp collisions at 13 TeV de-creases,leadingtoagrowingfractionofnewbosonsproducedoff mass-shell,towardslowermasses.Inthosecases,the K factor in-creasesandbecomessimilar tothelow-massvalues.Theproduct of the NNLO signal production cross section and branching frac-tion, σWB(W→ ν), with=e or μ, stronglydepends on the Wmass,varyingfrom111 pbfor M(W)=0.4 TeV to0.151 fbfor

M(W)=5.8 TeV.ForthebenchmarkmassesofM(W)=2.4 and 3.6 TeV,usedlater forillustration, thevaluesare 59.8and4.4 fb, respectively.ThewidthoftheSSMWisafunctionofitsmass.

All generated signal and background events are processed through a full simulation of the CMS detector based on Geant4 [27], and including an emulation of the trigger. The simulated eventsare reconstructed withthesamecode usedto reconstruct thedata.

Thesimulationofparticleproductionfromadditionalcollisions in the sameor nearby bunch crossing (pileup) is includedin all eventsamplesby superimposing minimumbiasinteractions onto thesimulatedevents,withafrequencydistributionmatchingthat observed in data. The average number ofinteractions per bunch crossingintheselecteddatais10.

4. Object identification and event selection

Events withatleastonehigh-pT lepton areselected using in-clusiveleptontriggers.Single-electrontriggerswithtransverse en-ergythresholdsof105or115 GeVandlooseelectronidentification criteriaareused.Thesingle-muontriggersrequire pT>45 GeV for amuonpseudorapidity,|η|<2.1,or pT>50 GeV for|η|<2.4 (the limitofcoverageofthemuondetectors).Therelativelyhigh elec-trontriggerthresholdisrequiredinordertosuppressnon-prompt

electronsandmisidentifiedjets.Theofflinereconstructed pTmust be greater than 130 (53) GeV in the electron (muon) channel, where the triggerefficiency reaches a plateauof 0.99 (0.96) rel-ativetothefullanalysisrequirementsdescribedinthefollowing.

Leptonsandp_Tmiss arereconstructedusingaparticle-flow tech-nique [28,29], an algorithm that combines measurements from all components of the CMS detector in order to reconstruct and identify individual particles in the event. Requirements for iden-tifying goodquality and energeticleptons are applied,optimized forhigh-pTvalueswheretheanalysishasthelargestsensitivityto theexpectedsignals. Eventscontaining calorimeternoiseorlarge

Emiss_T duetoinstrumental effects,such asbeamhalo orjetsnear nonfunctioningchannelsinthecalorimeters[30],arenotused.The primaryvertexintheeventisdefinedasthevertexwiththe high-estp2_T,wherethesumisoverthetracksassociatedtoit.

Electrons are reconstructed from electromagnetic energy de-posits(clusters)intheECALacceptanceregion(barrel,|η|<1.444, endcaps, 1.566<|η|<2.5) matched to a track in the silicon tracker [31]. The transverse energy of a localized cluster is de-finedas ET=E sinθ,withθ thepolaranglerelativeto thebeam axis,and wherethe cluster energy E includes any deposits con-sistent withbremsstrahlungemission. The electron identification, optimized for high-pT values [32,33], includes requirements on theisolation andon thevariables describing theelectromagnetic shower shape. The electron isolation is computedusing the sum ofthreeterms,basedontracker,ECAL,andHCALinformation, af-tercorrection for thecontributions expected fromdetectornoise andpileup.Theelectron isolationinthetrackerisensuredby re-quiring the scalar pT sum of all tracks, within a cone of R =



(η)2_{+ (φ)}2_{=0.3 centered around thetrackof theelectron} candidateandoriginatingfromtheprimaryvertex,tobelessthan 5 GeV.TheECALisolationisdefinedasthe ET sumoftheenergy depositswithin aconeofR =0.3 aroundtheelectroncandidate tobe lessthan 3%ofthe electron ET.The HCALisolation consid-ersthesumofenergydepositsinthehadroniccalorimeterwithin aconeofR =0.15 aroundtheelectrondirectionwhichmustbe lessthan 5% ofthe electron energydeposit inthe ECAL.In each casethesumsexcludetheelectroncandidateitself.Inorderto dif-ferentiatebetweenelectrons andphotonconversions,theelectron trackisrequiredtohavenomorethanonehitmissinginthepixel layers,andthetransversedistancetotheprimaryvertexmustbe lessthan0.02 (0.05) cminthebarrel(endcap). Theelectron mo-menta for electrons with pT≈45 GeV from Z→ee decays are estimated by combining energymeasurements in the ECAL with momentum measurements in the tracker. For high-energy elec-tronsthemomentumscaleandresolutionare dominatedentirely bytheenergymeasurementintheECAL.Thediscriminating vari-able inthissearch, MT, is moresensitive to variations of energy scalethantouncertaintyinenergyresolution.Theenergyscalehas thereforebeencheckedusinghigh-massoffshelldielectronevents comingfromZ-bosondecays.

Muons are reconstructed by combining the information from thetrackerandthemuonsystems[34,35].Eachmuonisrequired tohaveatleastone hitinthepixel detector,hitsinatleastfour layersofthestriptracker,andsegmentsintwoormoremuon de-tectorchambers. Sinceconsecutivelayers inthemuon systemare separated by thick layers of steel, the latter requirement signifi-cantlyreduces the amount of hadronicpunch-through. To reduce backgroundfromcosmicraymuons,eachmuonisrequiredtohave a transverse impact parameter lessthan 0.02 cmand a longitu-dinal distance parameter less than 0.5 cm. Both parameters are definedrelativetotheprimaryvertex.Inordertosuppressmuons withmismeasured pT,an additional requirement σpT/pT<0.3 is

applied,where σpT istheuncertaintyinthe pTfromthetrack

re-construction. Muon isolation requires that the scalar pT sum of

all tracksoriginatingfromtheinteractionvertexwithin aconeof

R =0.3 around its direction,excluding the muontrack, be less than 10% of the muon pT. The muon pT reconstruction is opti-mized forthehigh-pT regionandits performancehasbeen stud-ied usingboth high-energycosmic raymuonsanddimuons from high-pT Zbosondecays[33].Therelative pT resolutionformuons with pT<200 GeV is 1.3–2.0%in the barreland better than 6% in theendcaps. Forhigh-pT muons(pT up to 1 TeV)the relative resolutioninthebarrelisbetterthan10%.

To reduce the Drell–Yan background in each decay channel, eventswithadditionalelectrons(muons)of pT>35 (25) GeVand in|η|<2.5(2.4)arerejected.

Onceeventscontainingahigh-pT leptonareselected,the two-body decay kinematics of the W→ ν process is exploited to furtherreducethebackground,byapplyingtwoadditional require-ments,|φ(p_T,p_Tmiss)|>2.5 and0.4<p_T/Emiss_T <1.5.

The signal efficiency for the selection procedure, with no re-quirement on the reconstructed MT in the event, is determined from simulated samples and is maximal (≈0.80 for both decay channels) fora W boson of mass 1.5 TeV and decreases gradu-allyforlargerandsmallermassesdownto≈0.65.

5. Systematic uncertainties

The sources of systematic uncertainties of experimental na-turecanbedividedintothosethatarechannel-specificandthose that are common to the electron and muon channels. For each source of uncertainty, upper andlower valuesare propagated to the kinematicquantitiesofthedifferentobjects (e, μ,and Emiss_T ) in each event, the selection re-applied, and new MT values ob-tained,whichareconsideredinthestatisticalanalysisofthedata, aspresentedinthenextsection.

Mismeasurements of theelectron energyscale and resolution are typicallysmallanddonot changethe MT shapesignificantly. Thesystematicuncertaintyintheelectronenergyscalewastaken to be 2% [33]. For the electron energy resolution, an additional Gaussiansmearingof2%isappliedtotheonefromMCsimulation, to matchthe measurements performed on data using dielectron eventsfromZbosondecays.Theuncertaintyintheelectron iden-tificationefficiencywhenextrapolatedtohigh ETis4%(6%)inthe barrel(endcaps).Scale factorsare appliedto thesimulation sam-ples toaccountforpossibledifferencesbetweendataand simula-tionfortriggerefficiency.Theyaredeterminedwithanuncertainty of 0.2%(0.5%) forbarrel(endcaps),andare consistent withunity fortheelectrons.

Inthemuondecaychannel,the pT scaleissensitivetoan im-perfectmodelingofthealignmentinthetrackerormuonsystems. Studiesareperformedonthecurvatureofmuontracksindifferent regions of η and φ using high-pT cosmic ray data and dimuon events from collisions, together with the corresponding simula-tion samples.Theyindicate theabsenceofasignificant curvature bias. The uncertainties associatedwiththese resultsare takenas contributions totheoverall systematicuncertainties.Forthe cen-tral region(|η|<1.2)the biasuncertaintyis 0.03/TeVandinthe forward region (1.2<|η|<2.4) the bias uncertaintyis 0.04/TeV. These uncertainties are propagated to the muon pT assignment and consequently, to the MT distribution. The pT resolution at high-pT valuesin datais well reproduced by the simulationand no further correction is applied. Muon trigger and identification efficiencies measuredindataareconsistentwiththosefrom sim-ulatedsampleswithintheprecisionoftheefficiencymeasurement allowed bytheamountofdatacollectedathighpT.Uncertainties ontheextrapolationtohigh pTvaluesareassigned,whichincrease from3%for pT<500 GeV to8.5%forpT>1 TeV.

Fig. 2. DistributionsfordataandexpectedSMbackgroundsintheelectronchannel: transversemassMT(upper)andtheassociatedintegraldistribution(totalnumber

ofeventsaboveagivenvalueofMT)(lower).Theexpectedsignalsfromthe

de-caysofW bosonswith massesM(W)=2.4 and3.6 TeVarealso showninthe upperfigure.ThelowerpanelsshowtheratioofdatatoSMpredictions,wherethe bandcentered aroundunityindicatesthesystematicuncertaintyintheexpected background,excludingthe2.7%uncertaintyintheluminosity.

The sources of uncertainty in the lepton pT translate directly intothe Emiss

T calculation,which inthesampleofeventsselected ismainlydeterminedby thehigh pT ofthelepton. Aseventsare allowedto includean arbitrarynumberof jets,which may origi-natefrominitialstateradiation,systematicuncertaintiesinthejet energyscaleandresolutionarepropagatedtothe Emiss

T variable. Commontoboth theelectronandmuon channelsarethe un-certaintiesonthetotalintegratedluminosity(2.7%)[36]andinthe reweightingprocedureappliedtosimulatedsamplestomatchthe pileup in data (5%). The application of K factors accounting for higher-ordercorrections, bothforthesignalsandthebackground, is also affected by systematic uncertainties. The uncertainty in the signal K factor arises from the choice of PDF and αS. The combined uncertainty is evaluated using the PDF4LHC prescrip-tion [37], where in the computation of each PDF set the strong

Fig. 3. DistributionsfordataandexpectedSMbackgroundsinthemuonchannel: transversemassMT(upper)andtheassociatedintegraldistribution(totalnumber

ofeventsaboveagivenvalueofMT)(lower).Theexpectedsignalsfromthe

de-caysofW bosonswithmassesM(W)=2.4 and3.6 TeVarealsoshowninthe upperfigure.ThelowerpanelsshowtheratioofdatatoSMpredictions,wherethe bandcenteredaroundunityindicatesthesystematicuncertaintyintheexpected background,excludingthe2.7%uncertaintyintheluminosity.

couplingconstant is varied. UncertaintiesfromdifferentPDF sets and αS variation areadded inquadrature.For thebackground K factor,auniformuncertaintyof5%,stemmingfromtheNNLO cor-rections, is applied in addition toa mass-dependentuncertainty. The latter is determined by comparing the results fromthe two possible procedures forcombiningthe QCD andelectroweak cor-rections: additive or factorized methods [7]. The theoretical un-certainty related to the choice ofthe PDF set in the background modelingis estimatedusingthe PDF4LHCprescriptionand domi-natesthetotaluncertaintyathigh MT inbothdecaychannels. 6. Results

Fig. 2showsthedistributionoftransversemass MT(upper)and theassociated integraldistribution(total numberofeventsabove a given value of MT) (lower) for the electron decay channel for

Table 1

NumbersofeventsintheelectrondecaychannelintegratedaboveMTthresholdsof

500,1000,and1500 GeV,fordata,SMbackground,andsignalswithM(W)=2.4 and3.6 TeV.Theuncertaintiesincludesystematicandstatisticaluncertainties,but donotincludethe2.7%uncertaintyintheintegratedluminosity.

MT>500 GeV MT>1000 GeV MT>1500 GeV

Data 230 11 1

SM background 246±18 14.3±1.2 1.9±0.2 SSM M(W)=2.4 TeV 66.1±5.5 58.4±5.2 46.3±4.4 SSM M(W)=3.6 TeV 5.5±0.7 4.9±0.7 4.3±0.6 Table 2

NumbersofeventsinthemuondecaychannelintegratedaboveMTthresholdsof

500,1000,and1500 GeV,fordata,SMbackground,andsignalswithM(W)=2.4 and3.6 TeV.Theuncertaintiesincludestatisticalandsystematicuncertainties,but donotincludethe2.7%uncertaintyintheintegratedluminosity.

MT>500 GeV MT>1000 GeV MT>1500 GeV

Data 229 11 0

SM background 255±20 12.8±1.2 1.8±0.2 SSM M(W)=2.4 TeV 95.1±5.2 83.2±5.0 64.1±6.0 SSM M(W)=3.6 TeV 6.4±0.5 5.7±0.5 5.0±0.5 MT>200 GeV.The corresponding distributions arepresented for the muon channel inFig. 3 for MT>120 GeV, where the lower trigger pT threshold enables the extension of the distribution to lowertransversemasses.Theincreasingbinsizeathigh MT values inthe muon distribution reflects the degrading muon pT resolu-tion.Thehighest MTvalueobservedintheelectron(muon) chan-nel is 2.0 (1.2) TeV. The expected signals from the decay of W bosonswithmassesM(W)=2.4 and3.6 TeVarealsoshown.The lowerpanelsinthe MTdistributionspresentthedata-to-prediction ratiosandindicatereasonableagreementbetweendataandSM ex-pectations.

Tables 1 and2summarizethenumberofeventsexpectedfrom SM processes, compared to data, when integrating above three representative MT thresholds (500, 1000, and 1500 GeV) forthe electron and muon decay channels, respectively. Also shown are the number of expected signal events for W signals withmass

M(W)=2.4 and3.6 TeV.

6.1. Exclusion limits on SSM Wbosons

Upperlimitsontheproduct σWB(W→ ν),with=e or μ, are determined using a Bayesian approach with a uniform prior probability distributionforthesignal crosssection inthecontext ofSSM W boson production[38]. Ashape analysis(binned like-lihood) is performed where the likelihood function is based on probabilitydensityfunctionsdescribedbythe MT distributionsfor the expectedbackground processes,signals, anddata. Systematic uncertainties discussed in Section 5 in the expected signal and backgroundyields areincludedthroughnuisanceparameterswith log-normalpriordistributions.

Expectedandobserved95%CLlimitsasafunctionofWmass areshowninFig. 4intheelectron(upper)andmuon(lower) chan-nels,for M(W)>400 GeV.The SSMW NNLO crosssectionasa functionoftheWmassisalsodisplayed,togetherwiththe uncer-taintyassociatedwiththechoiceofPDFand αS,whichisshownas ashadedband.Withthepresentdatasample,SSMWresonances of masses less than 3.6 TeV (3.6 TeV expected) in the electron channel and less than 3.9 TeV (3.8 TeV expected) in the muon channelareexcludedat95% CL.Theseresultsprovidetighter lim-its thanthose obtainedfromRun 1data [7]. The combinationof theelectronandmuonchannels,whichhavecomparable sensitiv-ity,improvesthelimitsuchthattheproductionofSSMWbosons withmassesbelow4.1 TeV(4.0 TeVexpected)areexcludedat95%

Fig. 4. Expected andobserved95%CLlimitsfor theelectron(upper) andmuon (lower) decay channels.The expected(observed)limit isdisplayed asa dashed (solid)lineand theassociatedinner(outer)bandsrepresenttheone(two) stan-darddeviation(s.d.)uncertainties.TheSSMWNNLOcrosssectionsaredisplayed asafunctionofM(W).

Fig. 5. Expectedandobserved95%CLlimitsforthecombinationoftheelectronand muondecaychannels.Theexpected(observed)limitisdisplayedasadashed(solid) lineandtheassociatedinner(outer)bandsrepresenttheone(two)standard devia-tion(s.d.)uncertainties.TheSSMWNNLOcrosssectionisdisplayedasafunction ofM(W).

CL,asshowninFig. 5.Inmaking thiscombination, allsystematic uncertaintiesthatarecommontobothchannelsareassumedtobe fullycorrelated.

6.2. Combination with Run 1 results

AsimilarsearchforaWbosonintheelectronandmuon chan-nels wasperformedusingRun1dataat8 TeVcenter-of-mass

en-Fig. 6. Ratioofthecrosssectionlowerlimittothetheoreticalcrosssectionshownin red(lightercurves)forthe8 TeVdata,blue(darkercurves)forthe13 TeVdata,and blackforthecombineddatasetsintheelectron(upper)andmuon(lower)channels. Theobservedlimitsareshownwithsolidlinesandexpectedlimitswithdashed lines.FortheWmassrange400–4000 GeV,wherethecombinationislimitedby the8 TeVdataset,theone- andtwo-standarddeviation(s.d.)uncertaintybandsfor thecombinedlimitsareshowningreenandyellow,respectively.(Forinterpretation ofthereferencestocolorinthisfigurelegend,thereaderisreferredtotheweb versionofthisarticle.)

ergy[7].Theseresultscan becombinedwiththepresentanalysis usingtheprescriptionfromRef.[39].Thesystematicuncertainties are assumed to be uncorrelated between Run1 andRun 2. The 95% CL limits on the product σWB(W→ ν) derived from the combinationofdataat√s=8 and13 TeVarepresentedinFig. 6 fortheelectron (upper)andthemuon(lower) decaychannels.In thiscase,thecrosssectionsarepresentedrelativetothepredicted NNLOcrosssection fortheSSMW productionateach center-of-mass energy. The sensitivity to exclude high-mass W bosons is dominatedbythe datasetat√s=13 TeV, andthesedata deter-minethelimit exclusivelyformassesabove4 TeV.ForW masses below2.2 TeV,thehigherintegratedluminositydatasetfromthe 8 TeV Run still makes the biggest contribution to the sensitiv-ity.Considering bothdata sets, SSMW bosons withmasses less than 3.7 (3.9) TeV are excluded in the electron (muon) channel. Combiningbothfinalstatechannelsusingthedataatboth center-of-massenergies the production of SSM W bosons with masses below4.1 TeVisexcludedat95%CL.

6.3. Model-independent cross section limits

A cross section limit that is independent of the MT depen-denceexpectedin anygivenmodelis determined by performing asingle-bincountingexperimentinatransversemassrangeabove athreshold,denoted Mmin

T .Theresultsfortheelectronandmuon

Fig. 7. Expected(dashedline)andobserved(solidline)95%CLlimitforthe model-independentcrosssectionlimitasafunctionofthelowerMTthreshold,denoted

Mmin

T ,fortheelectronchannel(upperplot),themuonchannel(middleplot),and

thecombinedchannels(lowerplot).Theinner (outer)bandsrepresentthe one-(two-)standarddeviation(s.d.)uncertainties.

channels are shown in Fig. 7 along with the combination. Val-uesoftheproductofcrosssection andbranchingfractionsabove thesolid curve areexcluded. Theobservedcross sectionlimit in-cludesthefiducialacceptance, A, definedbythelepton geometri-cal acceptanceand the offline pT thresholds (Section4), aswell as detector effects and kinematic selection (back-to-back topol-ogy),denotedas .Bothquantitiesareevaluatedrelativetoevents generated with a transverse mass above the Mmin

T threshold.The fiducialacceptanceforverymassiveSSMWbosonsisoftheorder

of1,sincetheproducts oftheirdecayaremainlyemittedatvery highanglesrelativetothebeamdirection.

In order to compare a specific new model to the given cross sectionlimits,theeffectofthethreshold Mmin

T onthesignal accep-tancehastobetakenintoaccountbydeterminingtheratio( fMT)

ofthenumberofeventswith MT>Mmin_T tothenumberofevents generated.Forthe MTrangeshowninFig. 7thereconstruction ef-ficiencyisconstant andthe impactofthe MT resolutioneffectis negligible.Therefore fMT canbe evaluated atgenerator level.For

lower MT averysmall(<1%)differenceisexpectedbecauseofthe singlelepton triggerthreshold(130 GeVforelectrons,50 GeVfor muons).

Alimitontheproductofthecrosssectionandbranching frac-tion (σBA )excl can be obtainedby dividing theexcluded cross sectionofthemodel-independentlimit(σBA )MI giveninFig. 7 bythecalculatedfraction fMT(M

min T ): (σBA)excl= (σBA)MI(Mmin_T ) fMT(M min T ) .

Anydeviationinthevalueoftheproductofthefiducial accep-tanceandsignalefficiencyofthenewmodelfromthatappliedto the W inFig. 7would need tobe taken into consideration.The latter has a value of 0.83±0.03, where the quoted uncertainty correspondsto theestimatedvariation asa functionof Mmin_T .For apredictedmassivestatedecaying intotwoback-to-backleptons, thushavingsimilarkinematicpropertiestothose ofa genericW boson,thedeviationwouldbesmallandnoadditionalcorrection wouldberequired.

The validity of the model-independent limit procedure was checkedby applyingittoan SSMW bosonof3.6 TeV massand the results obtained are consistent with those presented in Sec-tion6.1usingthededicatedanalysis. Itshould benotedthatthis approachcorrespondstoasingle-binlimit,whichisexpectedtobe slightlylesssensitivethanthatobtainedfromadedicatedanalysis exploitingthefull MT shape.

7. Summary

A search has been performed for sequential standard model W bosons in final states containing a single energetic electron ormuon andlargemissingtransverse momentum,using proton– proton collision data at √s=13 TeV, corresponding to an inte-grated luminosity of2.3 fb−1. No deviationfromthe background expectationshas beenobserved andexclusionlimitsat 95% con-fidence level have been extracted on the mass of a W boson. Massesbelow 3.6 (3.9) TeVare excluded inthe electron (muon) decay channel analysis, significantly improving upon the results obtainedwiththe√s=8 TeV data.Thissearchhasbeencombined withtheearlierone conductedat8 TeV,wherethe sensitivityof thesearchisdominatedbythe13 TeVdata,yieldingalowermass limit of 4.1 TeV for W bosons when combining data from both decaychannelsandcenter-of-massenergies.Finally,genericlimits onthe productionofW resonanceswiththe sameleptonic final stateshavebeenobtainedusingamodel-independentapproach.

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,wegratefullyacknowledgethecomputingcentersand personneloftheWorldwideLHCComputingGridfordeliveringso effectivelythe computinginfrastructureessential to ouranalyses.

Finally, we acknowledge the enduring support for the construc-tion andoperationofthe LHCandtheCMSdetectorprovided by 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, andUASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland);FCT(Portugal);JINR(Dubna);MON,RosAtom,RAS,RFBR andRAEP(Russia);MESTD(Serbia);SEIDIandCPAN(Spain);Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA(Thailand); TÜBITAK and TAEK (Turkey); NASU andSFFR(Ukraine);STFC(UnitedKingdom);DOEandNSF(USA).

Individuals have received support from the Marie-Curie pro-gram and the European Research Council and EPLANET (Euro-pean Union); the Leventis Foundation; the A.P. Sloan Founda-tion; the Alexander von Humboldt Foundation; the Belgian Fed-eral 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 Technolo-gie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Scientific and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund, the Mobility Plus program of the Ministry of Science and Higher Education, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and 2015/19/B/ST2/ 02861, Sonata-bis 2012/07/E/ST2/01406; the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; the Na-tional Priorities Research Program by Qatar National Research Fund; the Programa Clarín-COFUND del Principado de Asturias; theRachadapisekSompotFundforPostdoctoralFellowship, Chula-longkornUniversityandtheChulalongkornAcademic intoIts2nd Century Project Advancement Project (Thailand); and the Welch Foundation,contractC-1845.

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The CMS Collaboration

V. Khachatryan,A.M. Sirunyan, A. Tumasyan YerevanPhysicsInstitute,Yerevan,Armenia

W. Adam, E. Asilar,T. Bergauer, J. Brandstetter, E. Brondolin, M. Dragicevic, J. Erö,M. Flechl, M. Friedl, R. Frühwirth1, V.M. Ghete, C. Hartl, N. Hörmann, J. Hrubec,M. Jeitler1,A. König, I. Krätschmer, D. Liko, T. Matsushita,I. Mikulec, D. Rabady, N. Rad, B. Rahbaran,H. Rohringer, J. Schieck1,J. Strauss,

W. Waltenberger, C.-E. Wulz1 InstitutfürHochenergiephysik,Wien,Austria

O. Dvornikov,V. Makarenko, V. Zykunov InstituteforNuclearProblems,Minsk,Belarus

V. Mossolov,N. Shumeiko,J. Suarez Gonzalez NationalCentreforParticleandHighEnergyPhysics,Minsk,Belarus

S. Alderweireldt, E.A. De Wolf,X. Janssen, J. Lauwers,M. Van De Klundert, H. Van Haevermaet, P. Van Mechelen, N. Van Remortel,A. Van Spilbeeck

UniversiteitAntwerpen,Antwerpen,Belgium

S. Abu Zeid,F. Blekman, J. D’Hondt, N. Daci, I. De Bruyn, K. Deroover, S. Lowette,S. Moortgat, L. Moreels, A. Olbrechts,Q. Python, 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, A. Léonard,J. Luetic, T. Maerschalk,A. Marinov, A. Randle-conde, T. Seva,

C. Vander Velde, P. Vanlaer, R. Yonamine,F. Zenoni, F. Zhang2 UniversitéLibredeBruxelles,Bruxelles,Belgium

A. Cimmino, T. Cornelis,D. Dobur, A. Fagot,G. Garcia,M. Gul, I. Khvastunov, D. Poyraz, S. Salva, R. Schöfbeck, A. Sharma,M. Tytgat, W. Van Driessche, E. Yazgan, N. Zaganidis

GhentUniversity,Ghent,Belgium

H. Bakhshiansohi,C. Beluffi3, O. Bondu,S. Brochet,G. Bruno, A. Caudron, S. De Visscher, C. Delaere, M. Delcourt, B. Francois,A. Giammanco, A. Jafari,P. Jez, M. Komm, V. Lemaitre, A. Magitteri,A. Mertens, M. Musich, C. Nuttens, K. Piotrzkowski,L. Quertenmont, M. Selvaggi, M. Vidal Marono, S. Wertz

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

UniversitédeMons,Mons,Belgium

W.L. Aldá Júnior, F.L. Alves,G.A. Alves, L. Brito,C. Hensel,A. Moraes, M.E. Pol, P. Rebello Teles CentroBrasileirodePesquisasFisicas,RiodeJaneiro,Brazil

E. Belchior Batista Das Chagas, W. Carvalho,J. Chinellato4,A. Custódio, E.M. Da Costa, G.G. Da Silveira5, D. De Jesus Damiao,C. De Oliveira Martins, S. Fonseca De Souza, L.M. Huertas Guativa, H. Malbouisson, D. Matos Figueiredo, C. Mora Herrera,L. Mundim, H. Nogima,W.L. Prado Da Silva, A. Santoro,

A. Sznajder,E.J. Tonelli Manganote4, A. Vilela Pereira UniversidadedoEstadodoRiodeJaneiro,RiodeJaneiro,Brazil

S. Ahujaa, C.A. Bernardesb, S. Dograa,T.R. Fernandez Perez Tomeia, E.M. Gregoresb, P.G. Mercadanteb, C.S. Moona, 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. Rodozov, S. Stoykova, G. Sultanov, M. Vutova InstituteforNuclearResearchandNuclearEnergy,Sofia,Bulgaria

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

W. Fang6

BeihangUniversity,Beijing,China

M. Ahmad, J.G. Bian, G.M. Chen, H.S. Chen,M. Chen, Y. Chen7,T. Cheng, C.H. Jiang, D. Leggat, Z. Liu, F. Romeo,S.M. Shaheen, A. Spiezia, J. Tao, C. Wang,Z. Wang, H. Zhang, J. Zhao

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,J.P. Gomez, C.F. González Hernández, J.D. Ruiz Alvarez, J.C. Sanabria

UniversidaddeLosAndes,Bogota,Colombia

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,S. Micanovic, L. Sudic,T. Susa InstituteRudjerBoskovic,Zagreb,Croatia

A. Attikis, G. Mavromanolakis,J. Mousa, C. Nicolaou, F. Ptochos,P.A. Razis, H. Rykaczewski, D. Tsiakkouri UniversityofCyprus,Nicosia,Cyprus

M. Finger8,M. Finger Jr.8 CharlesUniversity,Prague,CzechRepublic E. Carrera Jarrin

UniversidadSanFranciscodeQuito,Quito,Ecuador

A.A. Abdelalim9,10,Y. Mohammed11,E. Salama12,13

AcademyofScientificResearchandTechnologyoftheArabRepublicofEgypt,EgyptianNetworkofHighEnergyPhysics,Cairo,Egypt B. Calpas,M. Kadastik, M. Murumaa, 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, J. Tuominiemi,E. Tuovinen, L. Wendland

HelsinkiInstituteofPhysics,Helsinki,Finland J. Talvitie,T. Tuuva

LappeenrantaUniversityofTechnology,Lappeenranta,Finland

M. Besancon,F. Couderc, M. Dejardin, D. Denegri,B. Fabbro, J.L. Faure, C. Favaro, F. Ferri, S. Ganjour, S. Ghosh,A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry, I. Kucher, E. Locci,M. Machet, J. Malcles,J. Rander, A. Rosowsky, M. Titov, A. Zghiche

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

A. Abdulsalam,I. Antropov, S. Baffioni, F. Beaudette, P. Busson, L. Cadamuro, E. Chapon,C. Charlot, O. Davignon,R. Granier de Cassagnac, M. Jo, S. Lisniak,P. Miné, M. Nguyen, C. Ochando, G. Ortona, P. Paganini,P. Pigard, S. Regnard, R. Salerno,Y. Sirois, T. Strebler, Y. Yilmaz, A. Zabi

J.-L. Agram14, J. Andrea, A. Aubin, D. Bloch,J.-M. Brom, M. Buttignol,E.C. Chabert, N. Chanon, C. Collard, E. Conte14, X. Coubez, J.-C. Fontaine14,D. Gelé, U. Goerlach,A.-C. Le Bihan, K. Skovpen,P. Van Hove InstitutPluridisciplinaireHubertCurien(IPHC),UniversitédeStrasbourg,CNRS-IN2P3,France

S. Gadrat

CentredeCalculdel’InstitutNationaldePhysiqueNucleaireetdePhysiquedesParticules,CNRS/IN2P3,Villeurbanne,France

S. Beauceron,C. Bernet, G. Boudoul, E. Bouvier, C.A. Carrillo Montoya, R. Chierici,D. Contardo, B. Courbon, P. Depasse, H. El Mamouni, J. Fan, J. Fay, S. Gascon, M. Gouzevitch, G. Grenier, B. Ille, F. Lagarde, I.B. Laktineh,M. Lethuillier, L. Mirabito,A.L. Pequegnot, S. Perries, A. Popov15, D. Sabes, V. Sordini,M. Vander Donckt, P. Verdier,S. Viret

UniversitédeLyon,UniversitéClaudeBernardLyon1,CNRS-IN2P3,InstitutdePhysiqueNucléairedeLyon,Villeurbanne,France T. Toriashvili16

GeorgianTechnicalUniversity,Tbilisi,Georgia Z. Tsamalaidze8

TbilisiStateUniversity,Tbilisi,Georgia

C. Autermann, S. Beranek,L. Feld, A. Heister, M.K. Kiesel, K. Klein, M. Lipinski, A. Ostapchuk, M. Preuten, F. Raupach, S. Schael, C. Schomakers,J. Schulz, T. Verlage,H. Weber, V. Zhukov15

RWTHAachenUniversity,I.PhysikalischesInstitut,Aachen,Germany

A. Albert, F.F. Bispinck, M. Brodski, 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,L. Sonnenschein, D. Teyssier, S. Thüer

RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

V. Cherepanov, G. Flügge, F. Hoehle, B. Kargoll, T. Kress, A. Künsken,J. Lingemann, T. Müller, A. Nehrkorn, A. Nowack,I.M. Nugent, C. Pistone, O. Pooth,A. Stahl17

RWTHAachenUniversity,III.PhysikalischesInstitutB,Aachen,Germany

M. Aldaya Martin,T. Arndt, C. Asawatangtrakuldee, K. Beernaert,O. Behnke, U. Behrens,A.A. Bin Anuar, K. Borras18,A. Campbell, P. Connor, C. Contreras-Campana, F. Costanza, C. Diez Pardos,G. Dolinska, G. Eckerlin, D. Eckstein, T. Eichhorn, E. Eren, E. Gallo19,J. Garay Garcia, A. Geiser, A. Gizhko,

J.M. Grados Luyando, P. Gunnellini, A. Harb, J. Hauk, M. Hempel20,H. Jung, A. Kalogeropoulos, O. Karacheban20,M. Kasemann, J. Keaveney, C. Kleinwort,I. Korol, D. Krücker,W. Lange, A. Lelek,

J. Leonard, K. Lipka,A. Lobanov, W. Lohmann20,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.Ö. Sahin,P. Saxena, T. Schoerner-Sadenius,C. Seitz, S. Spannagel, N. Stefaniuk, G.P. Van Onsem,R. Walsh, C. Wissing

DeutschesElektronen-Synchrotron,Hamburg,Germany

V. Blobel, M. Centis Vignali, A.R. Draeger,T. Dreyer, E. Garutti, D. Gonzalez, J. Haller, M. Hoffmann, A. Junkes, R. Klanner, R. Kogler,N. Kovalchuk, V. Kutzner, T. Lapsien, T. Lenz, I. Marchesini,D. Marconi, M. Meyer, M. Niedziela, D. Nowatschin, F. Pantaleo17,T. Peiffer, A. Perieanu, J. Poehlsen,C. Sander, C. Scharf, P. Schleper, A. Schmidt, S. Schumann,J. Schwandt,H. Stadie, G. Steinbrück, F.M. Stober, M. Stöver, H. Tholen, D. Troendle,E. Usai, L. Vanelderen,A. Vanhoefer, B. Vormwald

M. Akbiyik, C. Barth,S. Baur, C. Baus, J. Berger,E. Butz, R. Caspart,T. Chwalek, F. Colombo, W. De Boer, A. Dierlamm,S. Fink, B. Freund,R. Friese, M. Giffels,A. Gilbert,P. Goldenzweig, D. Haitz,

F. Hartmann17, S.M. Heindl,U. Husemann, I. Katkov15,S. Kudella, P. Lobelle Pardo, H. Mildner,

M.U. Mozer,Th. Müller, M. Plagge, G. Quast, K. Rabbertz, S. Röcker, F. Roscher,M. Schröder, I. Shvetsov, G. Sieber,H.J. Simonis, R. Ulrich, J. Wagner-Kuhr, 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, E. Tziaferi NationalandKapodistrianUniversityofAthens,Athens,Greece

I. Evangelou,G. Flouris, C. Foudas, P. Kokkas, N. Loukas, N. Manthos,I. Papadopoulos, E. Paradas UniversityofIoánnina,Ioánnina,Greece

N. Filipovic

MTA-ELTELendületCMSParticleandNuclearPhysicsGroup,EötvösLorándUniversity,Budapest,Hungary

G. Bencze,C. Hajdu, P. Hidas,D. Horvath21, F. Sikler,V. Veszpremi, G. Vesztergombi22, A.J. Zsigmond WignerResearchCentreforPhysics,Budapest,Hungary

N. Beni,S. Czellar, J. Karancsi23,A. Makovec,J. Molnar, Z. Szillasi InstituteofNuclearResearchATOMKI,Debrecen,Hungary

M. Bartók22,P. Raics, Z.L. Trocsanyi, B. Ujvari InstituteofPhysics,UniversityofDebrecen,Hungary

S. Bahinipati, S. Choudhury24,P. Mal, K. Mandal, A. Nayak25,D.K. Sahoo, N. Sahoo,S.K. Swain NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

S. Bansal,S.B. Beri, V. Bhatnagar, R. Chawla, U. Bhawandeep, A.K. Kalsi,A. Kaur, M. Kaur, R. Kumar, P. Kumari,A. Mehta, M. Mittal, J.B. Singh, G. Walia

PanjabUniversity,Chandigarh,India

Ashok Kumar,A. Bhardwaj, B.C. Choudhary, R.B. Garg,S. Keshri, S. Malhotra,M. Naimuddin, N. Nishu, K. Ranjan,R. Sharma, V. Sharma

UniversityofDelhi,Delhi,India

R. Bhattacharya,S. Bhattacharya, K. Chatterjee, 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,Kolkata,India P.K. Behera

IndianInstituteofTechnologyMadras,Madras,India

R. Chudasama,D. Dutta, V. Jha, V. Kumar, A.K. Mohanty17, P.K. Netrakanti,L.M. Pant, P. Shukla,A. Topkar BhabhaAtomicResearchCentre,Mumbai,India

T. Aziz, S. Dugad,G. Kole, B. Mahakud, S. Mitra, G.B. Mohanty, B. Parida, N. Sur, B. Sutar TataInstituteofFundamentalResearch-A,Mumbai,India

S. Banerjee, S. Bhowmik26,R.K. Dewanjee, S. Ganguly, M. Guchait,Sa. Jain, S. Kumar, M. Maity26, G. Majumder, K. Mazumdar,T. Sarkar26, N. Wickramage27

TataInstituteofFundamentalResearch-B,Mumbai,India

S. Chauhan,S. Dube, V. Hegde, A. Kapoor, K. Kothekar, S. Pandey, A. Rane, S. Sharma IndianInstituteofScienceEducationandResearch(IISER),Pune,India

H. Behnamian,S. Chenarani28,E. Eskandari Tadavani,S.M. Etesami28, A. Fahim29, M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi30,F. Rezaei Hosseinabadi, B. Safarzadeh31, 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, L. Fiorea,G. Iasellia,c, 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,L. Silvestrisa,17, R. Vendittia,b, P. Verwilligena

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

G. Abbiendia,C. Battilana, D. Bonacorsia,b, S. Braibant-Giacomellia,b, L. Brigliadoria,b, R. Campaninia,b, P. Capiluppia,b,A. Castroa,b,F.R. Cavalloa,S.S. Chhibraa,b, G. Codispotia,b, M. Cuffiania,b,

G.M. Dallavallea,F. Fabbria, A. Fanfania,b, 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,b,17

a_{INFNSezionediBologna,Bologna,Italy} b_{UniversitàdiBologna,Bologna,Italy}

S. Albergoa,b,M. Chiorbolia,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, V. Ciullia,b,C. Civininia, R. D’Alessandroa,b,E. Focardia,b,V. Goria,b, P. Lenzia,b, M. Meschinia, S. Paolettia,G. Sguazzonia,L. Viliania,b,17

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

L. Benussi, S. Bianco, F. Fabbri,D. Piccolo, F. Primavera17 INFNLaboratoriNazionalidiFrascati,Frascati,Italy

V. Calvellia,b, F. Ferroa, M. Lo Veterea,b, M.R. Mongea,b,E. Robuttia,S. Tosia,b

a_{INFNSezionediGenova,Genova,Italy} b_{UniversitàdiGenova,Genova,Italy}

L. Brianza17, M.E. Dinardoa,b,S. Fiorendia,b,17,S. Gennaia, A. Ghezzia,b, P. Govonia,b, M. Malberti, S. Malvezzia, R.A. Manzonia,b,17,D. Menascea,L. Moronia, M. Paganonia,b,D. Pedrinia, S. Pigazzini, S. Ragazzia,b,T. Tabarelli de Fatisa,b

a_{INFNSezionediMilano-Bicocca,Milano,Italy} b_{UniversitàdiMilano-Bicocca,Milano,Italy}

S. Buontempoa, N. Cavalloa,c,G. De Nardo, S. Di Guidaa,d,17,M. Espositoa,b,F. Fabozzia,c, F. Fiengaa,b, A.O.M. Iorioa,b,G. Lanzaa,L. Listaa, S. Meolaa,d,17, P. Paoluccia,17, C. Sciaccaa,b, F. Thyssena,b

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

P. Azzia,17,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. Dossellia,F. Gasparinia,b,U. Gasparinia,b, A. Gozzelinoa, S. Lacapraraa,M. Margonia,b,

A.T. Meneguzzoa,b,J. Pazzinia,b,N. Pozzobona,b,P. Ronchesea,b, F. Simonettoa,b,E. Torassaa, M. Zanettia,b,P. Zottoa,b,G. Zumerlea,b

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

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

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

L. Alunni Solestizia,b, G.M. Bileia,D. Ciangottinia,b,L. Fanòa,b, P. Laricciaa,b, R. Leonardia,b, G. Mantovania,b, M. Menichellia,A. Sahaa,A. Santocchiaa,b

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

K. Androsova,32,P. Azzurria,17,G. Bagliesia,J. Bernardinia,T. Boccalia,R. Castaldia, M.A. Cioccia,32, R. Dell’Orsoa,S. Donatoa,c,G. Fedi, A. Giassia,M.T. Grippoa,32,F. Ligabuea,c, T. Lomtadzea, L. Martinia,b, A. Messineoa,b, F. Pallaa,A. Rizzia,b,A. Savoy-Navarroa,33, 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, D. Del Rea,b,17, M. Diemoza, S. Gellia,b, E. Longoa,b, F. Margarolia,b, B. Marzocchia,b,P. Meridiania, G. Organtinia,b,R. Paramattia, F. Preiatoa,b, S. Rahatloua,b,C. Rovellia, F. Santanastasioa,b

a_{INFNSezionediRoma,Roma,Italy} b_{UniversitàdiRoma,Roma,Italy}

N. Amapanea,b,R. Arcidiaconoa,c,17,S. Argiroa,b,M. Arneodoa,c,N. Bartosika,R. Bellana,b, C. Biinoa, N. Cartigliaa,M. Costaa,b, R. Covarellia,b,A. Deganoa,b,N. Demariaa, L. Fincoa,b, 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, V. Solaa,A. Solanoa,b,A. Staianoa,P. Traczyka,b, P.P. Trapania,b

a_{INFNSezionediTorino,Torino,Italy} b_{UniversitàdiTorino,Torino,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, Y.D. Oh, S. Sekmen,D.C. Son, Y.C. Yang KyungpookNationalUniversity,Daegu,RepublicofKorea

A. Lee

ChonbukNationalUniversity,Jeonju,RepublicofKorea H. Kim

ChonnamNationalUniversity,InstituteforUniverseandElementaryParticles,Kwangju,RepublicofKorea J.A. Brochero Cifuentes, T.J. Kim

HanyangUniversity,Seoul,RepublicofKorea

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

KoreaUniversity,Seoul,RepublicofKorea

J. Almond, J. Kim,H. Lee, S.B. Oh,B.C. Radburn-Smith, S.h. Seo, U.K. Yang, H.D. Yoo,G.B. Yu SeoulNationalUniversity,Seoul,RepublicofKorea

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

Y. Choi,J. Goh, C. Hwang, J. Lee,I. Yu SungkyunkwanUniversity,Suwon,RepublicofKorea

V. Dudenas, A. Juodagalvis,J. Vaitkus VilniusUniversity,Vilnius,Lithuania

I. Ahmed,Z.A. Ibrahim, J.R. Komaragiri, M.A.B. Md Ali34,F. Mohamad Idris35,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 Cruz36,A. Hernandez-Almada, R. Lopez-Fernandez, R. Magaña Villalba, J. Mejia Guisao,A. Sanchez-Hernandez

CentrodeInvestigacionydeEstudiosAvanzadosdelIPN,MexicoCity,Mexico

S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia UniversidadIberoamericana,MexicoCity,Mexico

S. Carpinteyro, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada BenemeritaUniversidadAutonomadePuebla,Puebla,Mexico

A. Morelos Pineda

UniversidadAutónomadeSanLuisPotosí,SanLuisPotosí,Mexico D. Krofcheck

P.H. Butler

UniversityofCanterbury,Christchurch,NewZealand

A. Ahmad, M. Ahmad, Q. Hassan,H.R. Hoorani, W.A. Khan,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. Byszuk37,K. Doroba, A. Kalinowski, M. Konecki,J. Krolikowski, M. Misiura, M. Olszewski,M. Walczak

InstituteofExperimentalPhysics,FacultyofPhysics,UniversityofWarsaw,Warsaw,Poland

P. Bargassa,C. Beirão Da Cruz E Silva, A. Di Francesco, P. Faccioli,P.G. Ferreira Parracho, M. Gallinaro, J. Hollar,N. Leonardo, L. Lloret Iglesias, M.V. Nemallapudi, J. Rodrigues Antunes,J. Seixas, O. Toldaiev, D. Vadruccio,J. Varela, P. Vischia

LaboratóriodeInstrumentaçãoeFísicaExperimentaldePartículas,Lisboa,Portugal

P. Bunin,M. Gavrilenko, I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin, G. Kozlov,A. Lanev,

A. Malakhov,V. Matveev38,39, V. Palichik,V. Perelygin, M. Savina, S. Shmatov, N. Skatchkov, V. Smirnov, N. Voytishin, A. Zarubin

JointInstituteforNuclearResearch,Dubna,Russia

L. Chtchipounov,V. Golovtsov, Y. Ivanov, V. Kim40, E. Kuznetsova41,V. Murzin, V. Oreshkin, V. Sulimov, 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, M. Toms, E. Vlasov,A. Zhokin

InstituteforTheoreticalandExperimentalPhysics,Moscow,Russia A. Bylinkin39

MoscowInstituteofPhysicsandTechnology,Moscow,Russia M. Chadeeva42, E. Popova,E. Tarkovskii

NationalResearchNuclearUniversity‘MoscowEngineeringPhysicsInstitute’(MEPhI),Moscow,Russia

V. Andreev,M. Azarkin39,I. Dremin39, M. Kirakosyan, A. Leonidov39,S.V. Rusakov, A. Terkulov P.N.LebedevPhysicalInstitute,Moscow,Russia

A. Baskakov,A. Belyaev, E. Boos,M. Dubinin43,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. Blinov44, Y. Skovpen44,D. Shtol44

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. Adzic45, P. Cirkovic, D. Devetak,M. Dordevic, J. Milosevic, V. Rekovic UniversityofBelgrade,FacultyofPhysicsandVincaInstituteofNuclearSciences,Belgrade,Serbia

J. Alcaraz Maestre, M. Barrio Luna,E. Calvo,M. Cerrada, M. Chamizo Llatas, 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, E. Navarro De Martino, A. Pérez-Calero Yzquierdo, J. Puerta Pelayo, A. Quintario Olmeda, I. Redondo,L. Romero,M.S. Soares CentrodeInvestigacionesEnergéticasMedioambientalesyTecnológicas(CIEMAT),Madrid,Spain

J.F. de Trocóniz, M. Missiroli, D. Moran UniversidadAutónomadeMadrid,Madrid,Spain

J. Cuevas, J. Fernandez Menendez,I. Gonzalez Caballero, J.R. González Fernández, E. Palencia Cortezon, S. Sanchez Cruz, I. Suárez Andrés,J.M. Vizan Garcia

UniversidaddeOviedo,Oviedo,Spain

I.J. Cabrillo, A. Calderon, J.R. Castiñeiras De Saa, E. Curras, M. Fernandez,J. Garcia-Ferrero, G. Gomez, A. Lopez Virto,J. Marco, C. Martinez Rivero, F. Matorras,J. Piedra 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, G. Auzinger, M. Bachtis,P. Baillon, A.H. Ball, D. Barney, P. Bloch, A. Bocci, A. Bonato, C. Botta,T. Camporesi, R. Castello, M. Cepeda, G. Cerminara, M. D’Alfonso,D. d’Enterria, A. Dabrowski,V. Daponte, A. David, M. De Gruttola, A. De Roeck, E. Di Marco46,M. Dobson, B. Dorney, T. du Pree,D. Duggan, M. Dünser, N. Dupont,A. Elliott-Peisert, S. Fartoukh, G. Franzoni, J. Fulcher, W. Funk, D. Gigi, K. Gill,M. Girone, F. Glege, D. Gulhan, S. Gundacker, M. Guthoff, J. Hammer, P. Harris, J. Hegeman,V. Innocente, P. Janot, J. Kieseler, H. Kirschenmann, V. Knünz,A. Kornmayer17,

M.J. Kortelainen, K. Kousouris,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. Milenovic47,F. Moortgat,

S. Morovic, 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. Rolandi48, M. Rovere,M. Ruan,H. Sakulin, J.B. Sauvan, C. Schäfer, C. Schwick,M. Seidel, A. Sharma,P. Silva, P. Sphicas49, J. Steggemann,M. Stoye, Y. Takahashi, M. Tosi,D. Treille, A. Triossi,A. Tsirou, V. Veckalns50, G.I. Veres22,N. Wardle, H.K. Wöhri, A. Zagozdzinska37,W.D. Zeuner

CERN,EuropeanOrganizationforNuclearResearch,Geneva,Switzerland

W. Bertl,K. Deiters, W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski,U. Langenegger, T. Rohe

PaulScherrerInstitut,Villigen,Switzerland

F. Bachmair, L. Bäni, L. Bianchini, B. Casal, G. Dissertori, M. Dittmar, M. Donegà, C. Grab, C. Heidegger, D. Hits, J. Hoss,G. Kasieczka, P. Lecomte†, W. Lustermann,B. Mangano, M. Marionneau,

P. Martinez Ruiz del Arbol, M. Masciovecchio, 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. Rossini, M. Schönenberger, A. Starodumov51,V.R. Tavolaro, K. Theofilatos,R. Wallny

T.K. Aarrestad, C. Amsler52, L. Caminada,M.F. Canelli,A. De Cosa, C. Galloni, A. Hinzmann, T. Hreus, B. Kilminster,J. Ngadiuba, D. Pinna,G. Rauco, P. Robmann, D. Salerno, Y. Yang, A. Zucchetta

UniversitätZürich,Zurich,Switzerland

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

NationalCentralUniversity,Chung-Li,Taiwan

Arun Kumar, P. Chang,Y.H. Chang, Y.W. Chang,Y. Chao, K.F. Chen, P.H. Chen, C. Dietz, F. Fiori, W.-S. Hou, Y. Hsiung, Y.F. Liu,R.-S. Lu, M. Miñano Moya,E. Paganis, A. Psallidas, J.f. Tsai, Y.M. Tzeng

NationalTaiwanUniversity(NTU),Taipei,Taiwan

B. Asavapibhop,G. Singh, N. Srimanobhas, N. Suwonjandee ChulalongkornUniversity,FacultyofScience,DepartmentofPhysics,Bangkok,Thailand

A. Adiguzel, S. Damarseckin, Z.S. Demiroglu, C. Dozen, E. Eskut, S. Girgis, G. Gokbulut, Y. Guler, I. Hos, E.E. Kangal53,O. Kara, A. Kayis Topaksu, U. Kiminsu,M. Oglakci, G. Onengut54,K. Ozdemir55,

S. Ozturk56,A. Polatoz, B. Tali57,S. Turkcapar,I.S. Zorbakir, C. Zorbilmez CukurovaUniversity- PhysicsDepartment,ScienceandArtFaculty,Adana,Turkey

B. Bilin,S. Bilmis, B. Isildak58,G. Karapinar59, M. Yalvac, M. Zeyrek MiddleEastTechnicalUniversity,PhysicsDepartment,Ankara,Turkey

E. Gülmez,M. Kaya60,O. Kaya61, E.A. Yetkin62, T. Yetkin63 BogaziciUniversity,Istanbul,Turkey

A. Cakir,K. Cankocak, S. Sen64 IstanbulTechnicalUniversity,Istanbul,Turkey B. Grynyov

InstituteforScintillationMaterialsofNationalAcademyofScienceofUkraine,Kharkov,Ukraine L. Levchuk,P. Sorokin

NationalScientificCenter,KharkovInstituteofPhysicsandTechnology,Kharkov,Ukraine

R. Aggleton,F. Ball, L. Beck, J.J. Brooke, D. Burns,E. Clement, D. Cussans, H. Flacher,J. Goldstein, M. Grimes, G.P. Heath, H.F. Heath,J. Jacob, L. Kreczko, C. Lucas, D.M. Newbold65, S. Paramesvaran, A. Poll, T. Sakuma,S. Seif El Nasr-storey, D. Smith,V.J. Smith

UniversityofBristol,Bristol,UnitedKingdom

K.W. Bell,A. Belyaev66,C. Brew, R.M. Brown, L. Calligaris,D. Cieri, D.J.A. Cockerill, J.A. Coughlan,

K. Harder,S. Harper, E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea,I.R. Tomalin, T. Williams RutherfordAppletonLaboratory,Didcot,UnitedKingdom

M. Baber,R. Bainbridge, O. Buchmuller, A. Bundock,D. Burton, S. Casasso,M. Citron, D. Colling, L. Corpe, P. Dauncey,G. Davies, A. De Wit, M. Della Negra, R. Di Maria, P. Dunne, A. Elwood, D. Futyan,Y. Haddad, G. Hall,G. Iles, T. James, R. Lane, C. Laner, R. Lucas65,L. Lyons, A.-M. Magnan,S. Malik, L. Mastrolorenzo, J. Nash, A. Nikitenko51,J. Pela, B. Penning, M. Pesaresi, D.M. Raymond, A. Richards,A. Rose,C. Seez, S. Summers,A. Tapper, K. Uchida, M. Vazquez Acosta67, T. Virdee17, J. Wright,S.C. Zenz