Measurement of the cross section for electroweak production of Z gamma in association with two jets and constraints on anomalous quartic gauge couplings in proton-proton collisions at root s=8 TeV

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Physics

Letters

B

www.elsevier.com/locate/physletb

Measurement

of

the

cross

section

for

electroweak

production

of

Zγ

in

association

with

two

jets

and

constraints

on

anomalous

quartic

gauge

couplings

in

proton–proton

collisions

at

√

s

=

8 TeV

.TheCMS Collaboration CERN,Switzerland

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

Articlehistory:

Received10February2017 Receivedinrevisedform9April2017 Accepted27April2017

Availableonline2May2017 Editor:M.Doser Keywords: CMS Physics aQGC Electroweakproduction

A measurement is presented of the cross section for the electroweak production of a Z boson and a photon in association with two jets in proton–proton collisions at √s=8 TeV. The Z bosons are identified through their decays to electron or muon pairs. The measurement is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb−1_{. The electroweak} contribution has a significance of 3.0 standard deviations, and the measured fiducial cross section is 1.86+₋0₀._.90₇₅(stat)₋+₀0._.34₂₆(syst)±0.05 (lumi) fb, while the summed electroweak and quantum chromodynamic total cross section in the same region is observed to be 5.94+₋1₁._.53₃₅(stat)₋+₀0._.43₃₇(syst)±0.13 (lumi) fb. Both

measurements are consistent with the leading-order standard model predictions. Limits on anomalous quartic gauge couplings are set based on the Zγ mass distribution.

©2017 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3_.

1. Introduction

With the discovery of the Higgs boson at the CERN LHC [1, 2], the standard model (SM) became a great success. The high energy and luminosity of the LHC provides the opportunity to observe many processes that are predicted by the SM, includ-ing electroweak production of multiple gauge bosons (WVγ [3], Vγ γ [4–6]), vector boson scattering (VBS) (same charge W±W± scattering [7–9], γ γ →W+W− [10], EW Wγjj [11], W±Z [12]), andvector bosonfusion(VBF) (EWW(Z)jj [13–16]). Samecharge W±W± scattering has been observed by ATLAS, and the exclu-sive γ γ→W+W− processbyCMS,bothwithsignificanceslarger than3standarddeviations.Thetribosonfinal stateZγ γ hasbeen observedbyATLASandCMSwithasignificancelargerthan5 stan-dard deviations. The EW productionof a Z boson (decaying into two oppositely-charged leptons), a photon, and two jets (hence-forth denoted Zγjj) has never been studied before, and is the subjectof thispaper. While the crosssection forquantum chro-modynamic(QCD)inducedZγjj productionisordersofmagnitude largerthan theone forEW production,thelattercan be usedto perform important tests of the SM, and to search for

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

tions fromphysicsbeyondtheSM thatcouldmanifestthemselves asanomaloustrilinearorquarticgauge bosoncouplings(aTGCor aQGC[3–7,9–12]).

This letterpresentsameasurement oftheassociated EW pro-duction of Zγjj, using the 8 TeV proton–proton collision data recorded by the CMS detector. The major processes contributing to EWZγjj production arerepresentedby theFeynmandiagrams inFig. 1.Theyare(a) bremsstrahlung,(b) multiperipheral(or non-resonant)production,(c, d) VBFwitheithertwotrilineargauge bo-soncouplings(TGC),or(e) VBSwithquarticgaugebosoncouplings (QGC).TheVBSprocessesareparticularlyinterestingbecausethey involve QGCs(e.g.WWZγ). Itis not possible,however,to isolate theQGCprocessesfromtheothercontributions,such asthe dou-ble TGC processes that are topologically similar. The interference oftheVBS diagramsensuresunitarity ofthe VBScrosssection in theSMathighenergy.Wepresentmeasurementsofthecombined cross sections for all EW processes that result in the Zγjj final state. The main background sourceis Zγjj productionwhere the associatedjetsareproducedthroughQCD-inducedprocesses(such astheFeynman diagramgiveninFig. 1(f)).Otherbackgrounds in-cludejetsorleptonsmisidentifiedasphotons,dibosonprocessesin which aW orZbosondecaysintotwo jetsandthe photon orig-inates frominitialorfinal-state radiation,andcontributionsfrom topquarkpairsandsingletopquarkproduction.

http://dx.doi.org/10.1016/j.physletb.2017.04.071

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

Fig. 1. RepresentativediagramsforEWZγjj productionattheLHC:(a)bremsstrahlung,(b)multiperipheral,(c,d)VBFwithTGC,(e)VBSincludingQGC,and(f)Example diagramfortheQCDZγjj production.

2. TheCMSdetector

The central feature of the CMS apparatus is a superconduct-ingsolenoidof 6 minternal diameter,providing amagnetic field of3.8 T.Withinthesolenoidvolumeare asilicon pixelandstrip tracker,aleadtungstatecrystalelectromagneticcalorimeter(ECAL), andabrassandscintillatorhadroncalorimeter(HCAL),each com-posedofa barreland twoendcap sections.Forwardcalorimeters extendthepseudorapidity, η,coverage providedbythebarreland endcapdetectors.Muonsaremeasuredingas-ionizationdetectors embeddedinthesteelflux-returnyokeoutsidethesolenoid.

Theparticle-flow(PF)eventalgorithm[17,18]reconstructsand identifieseach individual particlewithan optimizedcombination of information from the various elements of the CMS detector. The energy of photons is directly obtainedfrom the ECAL mea-surement, corrected for zero-suppression effects. The energy of electrons is determined from a combinationof the electron mo-mentum at the primary interaction vertex as determined by the tracker,theenergyofthecorrespondingECALcluster,andthe en-ergysumofallbremsstrahlungphotonsspatially compatiblewith originatingfrom the electron track.The energy of muonsis ob-tainedfromthecurvatureofthecorresponding track.Theenergy ofchargedhadronsisdeterminedfromacombinationoftheir mo-mentummeasuredinthetrackerandthematchingECALandHCAL energydeposits,correctedforzero-suppressioneffectsandforthe responsefunctionofthecalorimeterstohadronicshowers.Finally, theenergyofneutralhadronsisobtainedfromthecorresponding correctedECALandHCALenergy.

InthebarrelsectionoftheECAL,anenergyresolutionofabout 1% isachievedfor unconverted orlate-converting photonsinthe tensofGeVenergyrange.Theresolutionforother photonsinthe barrel section is about 1.3% up to |η|=1, rising to about 2.5% at |η|=1.4. In the endcaps, the resolution for unconverted or late-converting photonsis about2.5%, andthe resolution forthe remainingphotonsintheendcapisbetween3%and4%[19].When combininginformationfromtheentiredetector,thejetenergy res-olutionistypically15%at10 GeV,8%at100 GeV,and4%at1 TeV. Muons are measured in the range of |η|<2.4, with detec-tionplanesutilizingthree technologies:drift tubes,cathode strip chambers,andresistive-platechambers.Matchingmuonstotracks

measuredinthesilicontrackerresultsinapTresolutionformuons

with20<pT<100 GeV of1.3–2.0%inthebarrelandbetterthan

6%intheendcaps.

Theelectronmomentumisestimatedbycombiningtheenergy measurement in the ECAL withthe momentum measurement in the tracker. The momentum resolution for electrons with trans-verse momentum pT≈45 GeV from Z→ee decays ranges from

1.7% for nonshowering electrons in the barrelregion to 4.5% for showering electrons in the endcaps. The dielectron mass resolu-tionforZ→ee decaysis1.9%whenbothelectronsareintheECAL barrel,and2.9%whenbothelectronsareintheendcaps.

AmoredetaileddescriptionoftheCMSdetector,togetherwith adefinitionofthe coordinatesystemusedandtherelevant kine-maticvariables,canbefoundinRef.[20].

3. Eventreconstructionandselection

Candidateeventsare selectedonlinewithtriggers thatrequire two muons or electrons, where the leading andsubleading lep-tonshavepT>17 and8 GeV respectively,with|η|<2.4 (muons)

or|η|<2.5 (electrons).Theoverall triggerefficiencyisabout94% and 90% formuons and electrons, respectively, witha small de-pendenceonpTand η.

Muonsarereconstructedwithaglobalfitusingboththeinner trackingsystemandthemuonspectrometer. Anisolation require-mentisappliedinordertosuppressthebackgroundfrommultijet events[21,22].Electroncandidatesarereconstructedby matching energydepositsintheECALwithreconstructedtracks;they must pass stringent quality criteriaand an isolation requirement [23]. Chargedleptons mustoriginate fromtheprimary vertex,whichis defined asthe vertex whose tracks havethe highest sum of p2_T. We require that each event has exactly two oppositely charged muons(electrons) with pT>20 GeV and |η|<2.4(2.5) andthat

theinvariantmassofthedileptonsystemmustsatisfy70<M<

110 GeV.Theselectionefficienciesforleptonsaremeasuredusing thetag-and-probemethod[24]andareapproximately96%forthe muons[25]and80%fortheelectrons[21].

Photon candidates are reconstructed from energy deposits in the ECALwith no associatedtrack. Quality selection criteria[19]

Table 1

Summaryofthethreedifferenteventcriteria:(1)selectionfortheEWsignalmeasurement;(2)thecrosssection measurement;and(3)theselectionfortheaQGCsearch.“j1”and“j2”representthejetsthathavethelargestand second-largestpT,“1”and“2”denotetheleptonandantileptonfromthedecayoftheZboson,y istherapidity, φZγ ,jjistheabsolutedifferencebetween φZγ and φj1j2,andtheangularseparation R=

 (η)2_{+ (φ)}2_. Common selection pj1T,j2>30 GeV,|ηj1,j2| <4.7 p_T1,2>20 GeV,|η1,2_{| <2} .4 |ηγ_{| <1.4442} Mjj>150 GeV 70<M<110 GeV

EW signal measurement Fiducial cross section aQGC search

pγT>25 GeV p γ T>20 GeV p γ T>60 GeV |ηjj| >1.6 |ηjj| >2.5 |ηjj| >2.5 Rj>0.3,Rjj,γj,γ >0.5 Rjj,γj,γ ,j>0.4 Rj>0.3,Rjj,γj,γ >0.5 |yZγ− (yj1+yj2)/2| <1.2 Mjj>400 GeV Mjj>400 GeV φZγ ,jj>2.0 radians

Mjj>400 GeV with two divided regions

400<Mjj<800 GeV and Mjj>800 GeV

are applied to the reconstructed photons to suppress the back-ground from hadrons misidentified as photons. The observables usedin thephoton selection are: (1) PF-basedisolation variables that are corrected for the contribution from additional proton– protoncollisionsinthe samebunchcrossing(pileup);(2) a small ratio of hadronic energy in the HCAL to electromagnetic energy in the ECAL matched in (η,φ) (where φ is azimuthal angle in radians); (3) thetransverse widthof theelectromagnetic shower along the η direction [19]; and (4) an electron track veto. We consideronlyphotonsintheECALbarrelregion(|η|<1.44) with pT>25 GeV.Eventswiththephotoncandidateinoneofthe

end-caps (|η|>1.57) are excluded from the selection because their signalpurityislowerandsystematicuncertaintiesarelarge.

Hadronic jets are formed from the particles reconstructed by thePFalgorithm,usingthe FastJet softwarepackage[26]andthe anti-kT jetclustering algorithm[27] withadistanceparameter of

0.5. To reduce the contamination from pileup,charged PF candi-datesinthetrackeracceptanceregion|η|<2.4,areexcludedfrom thejetclusteringprocedureifassociatedwithpileupvertices.The contributionofneutralparticles frompileupeventstothe jet en-ergyistakenintoaccountby meansofacorrectionbasedonthe projected area ofthe jet onthe front faceof thecalorimeter. Jet energycorrectionsarederivedfromameasurementofthepT

bal-anceindijetandphoton+jeteventsindata[28].Furtherresidual corrections as functionsof pT and η are applied to the data to

correctforthesmalldifferencesbetweendataandsimulation. Ad-ditionalquality criteriaare appliedtothejetsinordertoremove spurious jet-like features originatingfrom isolated noisepatterns in thecalorimeters or inthe tracker[29]. The two jetswiththe highest pT are taggedasthe signaljetsandare requiredtohave

pT>30 GeV and |η|<4.7. Since we are primarily interested in

theVBStopologies,werequirethat theinvariantmassofthetwo jets,Mjj>150 GeV.

Table 1presentsa summary ofthethree differentsection cri-teria that are used for(1) the SM EW signal search, (2) the SM fiducial cross section measurement, and (3) the aQGC searches. The criteria isolate events consistent with the VBS topology of two high-energy scatteredjetsseparated by a large rapidity gap. Thecrosssectionmeasurementaddstwovariablessensitivetothe VBSprocess:|yZγ− (yj1+yj2)/2|,whichensurestheZγ systems

is located between the scattered jets in eta; and φZγ,jj, which

requiresthe Zγ system transversemomentum is consistent with recoilingagainst the transversemomentum ofthe twocombined jets.The fiducialcrosssection criteriaconstraintheVBS topology withonly basickinematic cutsthat define the acceptance ofthe

CMS detectorand a simple two dimensionalrequirement on the rapidityseparationandinvariantmassofthejets.Atightpγ_T selec-tionisappliedtoreachahigherexpectedsignificanceinasearch forapossibleaQGCsignalintheEWZγjj process.

4. Dataandsimulation

WeusedatacollectedwiththeCMSdetector,correspondingto an integratedluminosityof19.7 fb−1,atproton–proton center-of-massenergyof8 TeV.

TheEWsignal, Zγjj,atleading-order(LO),andthemain back-ground, QCD Zγ with 0–3additionaljets, forwhich the next-to-leading-order(NLO)QCDpredictionhasbeentakenfromRef.[30], matched withparton shower based on the so-called “MLM pre-scription” [31,32], are simulated using MadGraph v5.1.3.30 [33] interfaced with pythia v6.424 [34] for hadronization and show-ering,usingaCTEQ6L1partondistributionfunction(PDF)set[35]. The second significant background contribution comes from pro-cesseswhereajetismisidentifiedasaphoton(fakephoton),and thiscontributionisestimatedfromdata.Otherbackground contri-butions come fromdibosonprocesses (WW/WZ/ZZ)simulatedby pythia,singletop processessimulatedby powheg,andttγ simu-latedusing MadGraph interfacedwith pythia.The next-to-leading-order QCD cross sections are used to normalizethese simulated samples,exceptforttγ whereanLOpredictionistaken.

All thesimulatedeventsare processedthrough a Geant4[36] simulation of the CMS detector. The tag-and-probe technique is usedtocorrectfordata-MonteCarlo(MC)differencesinthetrigger efficiency, aswell asthe reconstructionandselection efficiencies. Additional proton–protoninteractions are superimposed over the hard scattering interaction with the distribution of primary ver-ticesmatchingthatobtainedfromthecollisiondata.

5. Backgroundmodeling

The dominant source of backgroundto the EW signal isQCD Zγ +jets production.The shapeofthisbackgroundistakenfrom MC simulationandthenormalizationis evaluatedfromdataina control region,definedas150<Mjj<400 GeV,wherethe signal

contribution is below 1%. The simulated MC events correctly re-produce theyieldoftheseeventswithacorrectionfactorof1.00 ±0.22forthecombinedZ→μ+μ−andZ→e+e− channels.The value is comparable with the NLO QCD K factor from Ref. [30], whichisaround1.1forMjj<400 GeV.

Fig. 2. TheMjjdistributionsmeasuredin(top)muonand(bottom)electron

chan-nels.The data(solidsymbols witherror barsrepresentingthe statistical uncer-tainties)arecomparedtoadata-drivenbackgroundestimate,combinedwith MC predictionsforthesignalcontribution.Thehashedbandsrepresentthefull uncer-taintyinthepredictions,asdescribedinSection6.Thelastbinincludesoverflow events.

The background from fake photons arises mainly from Z+jets eventswhereone jetsatisfiesthe photonID criteria. The estima-tionisbasedoneventssimilartotheonesselectedwiththe base-lineselectiondescribedinTable 1,exceptthatthephotonmustfail thetightphoton IDandsatisfy alooserID requirementbasedon thechargedisolationvariable.Thisselectionensuresthatthe pho-tonarisesfromajet,butstillhaskinematicpropertiessimilartoa genuinephoton satisfyingthetight photonID.We selectgenuine photonsusing σηη , a photon identification variable that exploits thesmalllateralextension oftheelectromagneticshower[25,19]. Based on the difference between the σηη distributions for fake photonsandgenuinephotons,afitismadetonormalizethe num-ber of events with fake photons to the number of events with genuine photons andobtain the probability to have a fake pho-ton. The fake photon probability is calculated based on different pγ_T regionsinamannersimilartothatdescribedinRef.[37].

Other backgrounds, including top quark and diboson produc-tionprocessesareestimatedfromMCsimulationsandnormalized totheintegratedluminosity ofthedatasample. Thecontribution fromthesebackgroundsislessthan 10% afterapplyingthe kine-maticselection(Section3)andisnegligibleoncethefinalEWand aQGCselectioncriteria(Sections7and8)areapplied.

The Mjj distributions for the Z→μ+μ− and e+e− channels

aftertheselectionrequirementsdescribed inSection 3are shown inFig. 2.Theobserveddistributionsarecomparedtothecombined predictionofthebackgroundsandoftheEWZγjj signal.

Table 2

Summaryofthemajoruncertainties.

Source Uncertainty

QCDZγ+jetsnormalization 22%(400<Mjj<800 GeV)

24%(Mjj>800 GeV)

Fakephotonfromjet (pγT dependent)

15%(20–30 GeV) 22%(30–50 GeV) 49%(>50 GeV)

Triggerefficiency 1.2%(Z→μ+μ−),1.7%(Z →e+e−) Leptonselectionefficiency 1.9%(Z→μ+μ−),1.0%(Z →e+e−) Jetenergyscaleandresolution 14%(Mjj>400 GeV)

ttγ crosssection 20%[3] Pileupmodeling 1.0% Renormalization/factorization scale(signal) 9.0%(400<Mjj<800 GeV) 12% (Mjj>800 GeV)(SM) 14%(aQGC) PDF(signal) 4.2%(400<Mjj<800 GeV) 2.4% (Mjj>800 GeV)(SM) 4.3%(aQGC)

Interference(signal) 18%(400<Mjj<800 GeV)

11% (Mjj>800 GeV)(SM)

Luminosity 2.6%

6. Systematicuncertainties

The systematicuncertainty inthe QCD Zγ + jetsbackground estimationis22% forbothZ→μ+μ− andZ→e+e−;it is dom-inated by the large statistical uncertainty in the control region usedfornormalization.Theshapeuncertaintiesthatarerelatedto the extrapolationofthe normalizationfactorto thesignal region (Mjj>400 GeV) are determined by varying the renormalization

andfactorizationscalesaswellastheMLMmatchingscale[31,32] upanddownbyafactoroftwo.Finally,wecombineboththe nor-malizationfactoruncertaintyandtheshapeuncertaintytoobtain thetotaluncertainty.

Thesystematicuncertaintyinthe backgroundestimationfrom fakephotonsarisesfromthevariationinthechoiceofthecharged isolationsidebandandthe σηη distributionusedforestimatingthe fakephotonprobability.Thetotaluncertaintiesinthefakephoton background estimation can be found in Table 2. The theoretical uncertaintyinthetopquarkbackgroundis20%[3].

The systematic uncertainties in the estimation of the trigger efficiency, measured using the tag-and-probe technique, are 1.2% and 1.7% for the Z→μ+μ− and Z→e+e− channels, respec-tively.Using similar methods, the systematicuncertainties inthe efficienciesforleptonreconstructionandidentificationinthetwo channelsare1.9%and1.0%,respectively.Thesystematicuncertainty inthejetenergyscaleandresolutionisestimatedbyvarying the jet energy scale and resolution up and down within their pT

-and η-dependent uncertainties [28]. The uncertainty is 14% for Mjj>400 GeV. Anothersource ofuncertainty isthe modeling of

thepileup.Theinelasticcrosssectionisvariedby±5%inorderto evaluatethiscontribution.Theuncertaintyintheintegrated lumi-nosityis2.6%[38].

Therearealsothreesourcesoftheoreticaluncertaintiesapplied tothesignalonly.ThePDF uncertaintyforthesignalisestimated with the CT10 [39] PDF set, following the asymmetric Hessian methodintroduced inRefs. [40,41].The scaleuncertaintyis eval-uated by varying the renormalizationandfactorization scales in-dependentlybyafactoroftwo.Themagnitudeoftheinterference betweenQCDandEWZγjj processesisassignedassystematic un-certaintiesinthetwo Mjjranges.

All the systematicuncertainties described are appliedto both the signal significance measurement and the aQGC search. They are also propagated to the uncertainty in the measured fiducial

Table 3

SignalandbackgroundyieldsafterthefinalselectionfortheSMmeasurement,for thetwobinsof400 <Mjj<800 GeV (upper)andMjj>800 GeV (lower).Only

sta-tisticaluncertaintiesarereported.

400<Mjj<800 GeV Muon Electron

Fake photon from jet 3.4±0.8 1.7±0.5 Other background 0.1±0.1 0.1±0.1 QCD Zγjj 4.8±0.9 5.0±1.0 EW Zγjj 1.7±0.1 1.8±0.1 Total background 8.3±1.2 6.8±1.1

Data 13 8

Mjj>800 GeV Muon Electron

Fake photon from jet 0.4±0.3 0.1±0.1 Other background 0±0 0±0 QCD Zγjj 0.4±0.1 1.1±0.2 EW Zγjj 1.8±0.1 1.8±0.1 Total background 0.8±0.3 1.2±0.2

Data 5 2

crosssection,withtheexceptionofthetheoreticaluncertainty as-sociatedwiththesignalcrosssection.

AlltheuncertaintiesinouranalysisaresummarizedinTable 2.

7. Measurementofthesignalsignificanceandfiducialcross section

As shown in Table 1, in addition to the common selection, we apply three further requirements to isolate the EW signal: |yZγ− (yj1+yj2)/2|<1.2,|ηjj|>1.6,andφZγ,jj>2.0 radians.

Theselectionrequirementsarechosenbyoptimizingtheexpected significance. We apply the CLs criterion described in Refs. [42,

43] to assess the signal significance, based on the binned Mjj

distribution, usingonly the two rightmost bins corresponding to 400<Mjj<800 GeV and Mjj>800 GeV. We consider QCD Zγjj

production and events without Zγ as background and EW Zγjj productionassignal.

Table 3 summarizes the numberof events predictedfor each processwiththenumberofeventsobserved.ForEWZγjj produc-tion, the observations are found to be compatiblewith expecta-tions in the differentchannels. By combining both channels, we find evidencefor EW Zγjj production withan observed and ex-pectedsignificanceof3.0and2.1standarddeviations,respectively. We determine the ratio of the observed signal to that expected from the SM for LO EW Zγjj production as μˆ =1.5+₋0₀._.9₆ using a binned likelihood fit over the two ranges of the Mjj

distribu-tion.

Applying the same criteria, we can also measure the signifi-cance of the combined EW and QCD Zγjj process. As shown in Table 3,withthetwo decaychannelscombinedinthe search re-gion,ofthesignal events7.0(38.4%)areestimatedtocome from EWproductionandtheremaining11.3fromQCDproduction.Asa result, theobserved(expected)significance forthecombinedEW andQCDZγjj processis5.7(5.5)standarddeviations.

TodeterminethecrosssectionforEWZγjj productionwe use a fiducial kinematic region based on the acceptance of the CMS detectorwithaminimalselectionontheMjjandηjjvariablesto

selecttheVBStopology.Thefiducialregionisdefinedasdescribed in Table 1. We define the cross section in the fiducial region as σf =σgμ αˆ g f where σg is the cross section for generated sig-nal events, μˆ is the signal strength, and αg f is the acceptance forthegeneratedeventsinthefiducial region,evaluatedthrough simulation. The fiducial cross section for EW Zγjj production is 1.86₋+0_0..90₇₅(stat)+₋0_0..34₂₆(syst)±0.05(lumi) fb,consistentwiththe the-oreticalpredictionatLOof1.27±0.11(scale)±0.05(PDF)fb cal-culatedusing MadGraph.

The cross section for all processes that produce the Zγjj fi-nal state can be compared to theoretical predictions. The fidu-cial region studied here lies in a particularly interesting region of phase space because of the substantial contribution to Zγjj from EW production. By restrictingthe phase space to the fidu-cial region for the EW process as defined before, the expected fractionofEWeventsinthecombinedsampleofEWandQCD sig-nal eventsis26%, andthecross sectionof thecombinedprocess is 5.94₋+₁1._.53₃₅(stat)+₋₀0_..43₃₇(syst)±0.13(lumi) fb, which is consistent withthetheoreticalpredictionatLOcalculatedusing MadGraph: 5.05±1.22(scale)±0.31(PDF)fb.

8. Searchforanomalousquarticgaugecouplings

TheeffectsofanynewphysicsbetweentheTeVandthePlanck scalemightbesignificantinthehighenergytailsofmeasurements attheLHCandcanbeparameterizedviaeffectiveanomalous cou-plings.WiththediscoveryoftheHiggsboson,higher-dimensional operatorscanbeintroducedinalinearway[44]:

LaQGC= fM0 4 Tr  WμνWμν×  (Dβ )†Dβ  + fM1 4 Tr  WμνWνβ×  (Dβ )†Dμ  + fM2 4  BμνBμν×  (Dβ )†Dβ  + fM3 4  BμνBνβ  ×(Dβ )†Dμ  + fT0 4T r[ ˆWμνWˆ μν_{] ×T r[ ˆW} αβWˆαβ] + fT2 4 T r[ ˆWαμWˆ μβ_{] ×T r[ ˆW} βνWˆνα] + fT8 4BμνB μν_B αβBαβ+ fT9 4BαμB μβ_B βνBνα, (1)

where fM0,1,2,3 and fT0,2,8,9 are coefficients ofrelevant effective

operators, andrepresents thescale ofnewphysics responsible for anomalous couplings. The Lagrangian of the aQGCsis imple-mentedwithinthe MadGraph package.

Westudythedistributionofthemassofthedileptonand pho-ton system, MZγ ,tosearch forcontributionsfromaQGCs.The ef-fectsof newphysicswouldbe seen athigherenergyandmodify the interference of VBS diagrams. To select the region sensitive to new physics, we require pγ_T >60 GeV. The selection for the aQGC analysisis described in Table 1. The Zγ mass distribution is shown in Fig. 3, where the last bin includes all events with MZγ>420 GeV.Becausenosignificantexcessisseen intheMZγ distribution, we usetheshape ofthe MZγ distributionto extract limitsonaQGCcontributions.

Withtheparameterizationofsignalsandrelatedsystematic un-certainties, foreach aQGC parameter, we reweight theSM signal shapetotheaQGCshape.Thefollowingteststatisticisused:

tαtest= −2 ln

L(αtest, ˆˆθ )

L(αˆ, ˆθ ) , (2)

where the likelihood function (L) is constructed for both lepton channelsandcombined,usingabin-wisePoissondistributionwith profiled nuisanceparameters (θ). αtest represents theaQGC point

being tested. The symbol ˆˆθ represents the values corresponding tothemaximumofthelikelihoodatthepoint αtest,whileαˆ and

ˆθ correspond to the globalmaximum ofthe likelihood. This test statistic isassumed tofollow a χ2 _{distribution [45], fromwhich}

Fig. 3. TheinvariantmassdistributionoftheZγ systemforeventsthatpassthe aQGCselection.Thehighestmassbinincludeseventswith MZγ>420 GeV.Error

barsrepresentthestatisticaluncertaintyinthedata,whilethesystematic uncer-taintiesintheaQGCsignalandbackgroundestimateareshownashatchedbands.

Table 4

Observedandexpectedshape-basedexclusionlimitsforeachaQGC param-eterat95%CL,withoutaformfactorapplied.

Observed limits (TeV−4_{) Expected limits (TeV}−4₎ −71<fM0/4<75 −109<fM0/4<111 −190<fM1/4<182 −281<fM1/4<280 −32<fM2/4<31 −47<fM2/4<47 −58<fM3/4<59 −87<fM3/4<87 −3.8<fT0/4<3.4 −5.1<fT0/4<5.1 −4.4<fT1/4<4.4 −6.5<fT1/4<6.5 −9.9<fT2/4<9.0 −14.0<fT2/4<14.5 −1.8<fT8/4<1.8 −2.7<fT8/4<2.7 −4.0<fT9/4<4.0 −6.0<fT9/4<6.0

couplingparameterisvaried overasetofdiscretevalues,keeping theotherparametersfixedtozero.

An effective theory is only valid at energies lower than the scaleofnewphysics,andhigh-dimensionaloperatorswithnonzero aQGCvaluescanleadtounitarityviolationatsufficientlyhigh en-ergies.ForeachaQGClistedinTable 4,wecheckedthestated up-perlimitagainsttheunitarybound[46]obtainedwith vbfnlo[47]. Ingeneral,wefindthelimitsonallaQGCparametersaresetinthe unitaryunsaferegion,exceptfor fT9 wheretheunitarityboundis

upto6 TeV.Formfactorscan beintroducedtounitarizethehigh energycontribution,howeveritisdifficulttocompareresultsfrom differentexperimentsanditisnottheoreticallywellmotivated.In thisstudyall ofthe aQGC limitsshown are evaluated without a formfactor, and can be directly compared to limits set in refer-ences[3–7,9–12].

9. Conclusions

Themeasurementofthecrosssectionfortheelectroweak pro-duction ofa Z boson anda photon in association withtwo jets, wherethe Z boson decaysinto electronor muonpairs, was pre-sented.The measurement isbasedon asample ofproton–proton collisions collected with the CMS detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb−1_{.Wefindevidence forEWZγjj productionwithan}

ob-served(expected)significanceof3.0(2.1)standarddeviations.The fiducial cross section forEW Zγjj production is measured to be 1.86₋+0_0..90₇₅(stat)+₋0_0..34₂₆(syst)±0.05(lumi) fb,consistentwiththe the-oreticalprediction.ThefiducialcrosssectionforcombinedEWand QCD Zγjj production is5.94+₋1_1..₃₅53(stat)+₋0₀._.43₃₇(syst)±0.13(lumi) fb, whichisalsoconsistentwiththeleading-ordertheoretical predic-tion.

Intheframework ofdimension-eight effectivefieldtheory op-erators,limitsontheaQGCparameters fM0,1,2,3 and fT0,1,2,8,9are

setat95%confidencelevel.Thisisthefirstconstraintsonthe neu-tralaQGCparameters fT8.

Acknowledgements

WecongratulateourcolleaguesintheCERNaccelerator depart-ments for the excellent performance of the LHC and thank the technicalandadministrative staffsatCERN 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-tionandoperation oftheLHC andtheCMSdetectorprovidedby 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);MOEandUM (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);SEIDI,CPAN, PCTIandFEDER (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-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) ofthe Czech Republic;the Council ofScience and Indus-trial Research, India; the HOMING PLUS program of the Foun-dation for Polish Science, cofinanced from European Union, Re-gional 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-bis2012/07/E/ST2/01406;theNationalPriorities Re-search Program by Qatar National Research Fund; the Programa Clarín-COFUND del Principado de Asturias; the Thalis and Aris-teia programs cofinanced by EU-ESF and the Greek NSRF; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chula-longkornUniversityandtheChulalongkornAcademic intoIts2nd Century Project Advancement Project (Thailand); and the Welch Foundation,contractC-1845.

References

[1] ATLASCollaboration,Observationofanewparticleinthesearchforthe Stan-dardModelHiggsbosonwiththeATLASdetectorattheLHC,Phys.Lett.B716 (2012)1,http://dx.doi.org/10.1016/j.physletb.2012.08.020,arXiv:1207.7214. [2] CMSCollaboration,Observationofanewboson atamassof125GeVwith

theCMSexperimentattheLHC,Phys.Lett.B716(2012)30,http://dx.doi.org/ 10.1016/j.physletb.2012.08.021,arXiv:1207.7235.

[3] CMS Collaboration, A search for W Wγ and W Zγ production and con-straintsonanomalousquarticgaugecouplingsinppcollisionsat√s=8 TeV, Phys.Rev.D90(2014)032008,http://dx.doi.org/10.1103/PhysRevD.90.032008, arXiv:1404.4619.

[4] ATLASCollaboration, EvidenceofWγ γ productioninppcollisionsat√s=

8 TeV andlimitsonanomalousquarticgaugecouplingswiththeATLAS detec-tor,Phys.Rev.Lett.115(2015)031802,http://dx.doi.org/10.1103/PhysRevLett. 115.031802,arXiv:1503.03243.

[5] ATLASCollaboration,MeasurementsofZγ and Zγ γ productioninpp colli-sionsat√s=8 TeV withtheATLASdetector,Phys.Rev.D93(2016)112002,

http://dx.doi.org/10.1103/PhysRevD.93.112002,arXiv:1604.05232.

[6] CMSCollaboration,Measurementsofthepp→W±γ γ andpp→Zγ γ Cross SectionsandLimitsonDimension-8EffectiveAnomalousGaugeCouplingsat

√

s=8 TeV,CMSPhysicsAnalysisSummaryCMS-PAS-SMP-15-008,2016,URL:

http://cds.cern.ch/record/2130360.

[7] ATLASCollaboration,EvidenceforelectroweakproductionofW±W±jjinpp

collisionsat√s=8 TeV withtheATLASdetector,Phys.Rev.Lett.113(2014) 141803,http://dx.doi.org/10.1103/PhysRevLett.113.141803,arXiv:1405.6241. [8]ATLAS Collaboration, Measurement of W±W± vector-boson scatteringand

limitsonanomalousquarticgaugecouplingswith theATLASdetector,Phys. Rev.D(2016),arXiv:1611.02428,submittedforpublication.

[9] CMSCollaboration,Studyofvectorbosonscatteringandsearchfornewphysics ineventswithtwosame-signleptonsandtwojets,Phys.Rev.Lett.114(2014) 051801,http://dx.doi.org/10.1103/PhysRevLett.114.051801,arXiv:1410.6315. [10] CMSCollaboration,Evidenceforexclusiveγ γtoW+W−productionand

con-straintsonanomalousquarticgaugecouplingsat√s=7 and8 TeV,J.High EnergyPhys.08(2016)119,http://dx.doi.org/10.1007/JHEP08(2016)119,arXiv: 1604.04464.

[11]CMS Collaboration, Measurement of electroweak-induced production of W gamma with two jets in pp collisions at √(s)=8 TeV and constraints on anomalous quartic gauge couplings, J. High Energy Phys. (2016), arXiv:1612.09256,submittedforpublication.

[12] ATLASCollaboration,MeasurementsofW±Z productioncrosssectionsinpp

collisionsat √s=8 TeVwiththeATLAS detectorand limitsonanomalous gaugebosonself-couplings,Phys.Rev.D93(2016)092004,http://dx.doi.org/ 10.1103/PhysRevD.93.092004,arXiv:1603.02151.

[13] CMSCollaboration,MeasurementofthehadronicactivityineventswithaZ andtwojetsandextractionofthecrosssectionfortheelectroweakproduction ofaZwithtwojetsinppcollisionsat√s=7 TeV,J.HighEnergyPhys.10 (2013)062,http://dx.doi.org/10.1007/JHEP10(2013)062,arXiv:1305.7389. [14] CMS Collaboration, Measurement ofelectroweak production of two jetsin

associationwith aZ bosoninproton–protoncollisions at √s=8 TeV, Eur. Phys.J.C75(2014)2,http://dx.doi.org/10.1140/epjc/s10052-014-3232-5,arXiv: 1410.3153.

[15] ATLASCollaboration,Measurementoftheelectroweakproductionofdijetsin association with a Z -bosonand distributions sensitive to vector boson fu-sion inproton–proton collisions at √s=8 TeV using the ATLAS detector, J. HighEnergyPhys.04(2013)031,http://dx.doi.org/10.1007/JHEP04(2014)031, arXiv:1401.7610.

[16] CMS Collaboration, Measurement ofelectroweak production of a Wboson andtwoforwardjetsinproton–protoncollisionsat√s=8 TeV,J. High En-ergy Phys. 11 (2016) 147, http://dx.doi.org/10.1007/JHEP11(2016)147, arXiv: 1607.06975.

[17] CMS Collaboration, Particle–Flow Event Reconstruction in CMSand Perfor-manceforJets,Taus,andEmiss

T ,CMSPhysicsAnalysisSummary

CMS-PAS-PFT-09-001,2009,URL:http://cds.cern.ch/record/1194487.

[18] CMS Collaboration, Commissioning of the Particle-Flow Event Reconstruc-tion with the First LHC Collisions Recorded in the CMS Detector, CMS PhysicsAnalysisSummaryCMS-PAS-PFT-10-001,2010,URL:http://cds.cern.ch/ record/1247373.

[19] CMSCollaboration, Performanceof photonreconstruction and identification withtheCMSdetectorinproton–protoncollisionsat√s=8 TeV,J.Instrum. 10 (2015) P08010, http://dx.doi.org/10.1088/1748-0221/10/08/P08010, arXiv: 1502.02702.

[20] CMSCollaboration,TheCMSexperimentattheCERNLHC,J.Instrum.3(2008) S08004,http://dx.doi.org/10.1088/1748-0221/3/08/S08004.

[21] CMS Collaboration, Performance of CMS muon reconstruction in pp colli-sion events at √s=7 TeV,J. Instrum. 7 (2012) P10002, http://dx.doi.org/ 10.1088/1748-0221/7/10/P10002,arXiv:1206.4071.

[22] CMS Collaboration, Measurementofthe Zγ production cross sectionin pp collisionsat 8TeV andsearch foranomalous triplegaugebosoncouplings, J. HighEnergyPhys.04(2015)164,http://dx.doi.org/10.1007/JHEP04(2015)164, arXiv:1502.05664.

[23] CMSCollaboration,EnergycalibrationandresolutionoftheCMS electromag-neticcalorimeterinppcollisionat√s=7 TeV,J.Instrum.8(2013)P09009,

http://dx.doi.org/10.1088/1748-0221/8/09/P09009,arXiv:1306.2016.

[24] CMSCollaboration,Measurementofthe inclusiveWandZproduction cross sectionsinpp collisionsat √s=7 TeV,J.HighEnergy Phys.10(2011)132,

http://dx.doi.org/10.1007/JHEP10(2011)132,arXiv:1107.4789.

[25] CMSCollaboration,Performanceofelectronreconstructionandselectionwith the CMS detector in proton–proton collisions at √s=8 TeV, J. Instrum. 10 (2015) P06005, http://dx.doi.org/10.1088/1748-0221/10/06/P06005, arXiv: 1502.02701.

[26] M.Cacciari,G.P.Salam,G.Soyez,FastJetusermanual,Eur.Phys.J.C72(2012) 1896,http://dx.doi.org/10.1140/epjc/s10052-012-1896-2,arXiv:1111.6097. [27] M.Cacciari,G.P.Salam,G.Soyez,Theanti-kTjetclusteringalgorithm,J.High

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

[28] CMSCollaboration,Determinationofjetenergycalibrationandtransverse mo-mentumresolution in CMS,J. Instrum. 6(2011) P11002, http://dx.doi.org/ 10.1088/1748-0221/6/11/P11002,arXiv:1107.4277.

[29] CMSCollaboration,JetPerformanceinppCollisionsat√s=7 TeV,CMSPhysics Analysis Summary CMS-PAS-JME-10-003, 2010, URL: http://cdsweb.cern.ch/ record/1279362.

[30] F.Campanario,M.Kerner,L.D.Ninh,D.Zeppenfeld,Zγ productionin associa-tionwithtwojetsatnext-to-leadingorderQCD,Eur.Phys.J.C74(2014)3085,

http://dx.doi.org/10.1140/epjc/s10052-014-3085-y,arXiv:1407.7857.

[31] M.L.Mangano,M.Moretti,F.Piccinini,M.Treccani,Matchingmatrixelements andshowerevolutionfortop-quarkproductioninhadroniccollisions,J.High EnergyPhys.01(2007)013,http://dx.doi.org/10.1088/1126-6708/2007/01/013, arXiv:hep-ph/0611129.

[32] J.Alwall,S.Höche,F.Krauss,N.Lavesson,L.Lönnblad,F.Maltoni,M.L.Mangano, M.Moretti,C.G.Papadopoulos,F.Piccinini,S.Schumann,M.Treccani,J.Winter, M.Worek,Comparativestudyofvariousalgorithmsforthemergingofparton showersandmatrixelementsinhadroniccollisions,Eur.Phys.J.C53(2008) 473,http://dx.doi.org/10.1140/epjc/s10052-007-0490-5,arXiv:0706.2569. [33] J.Alwall, M. Herquet,F.Maltoni, O.Mattelaer, T. Stelzer,MadGraph5:

go-ing beyond,J. High Energy Phys. 06 (2011) 128, http://dx.doi.org/10.1007/ JHEP06(2011)128,arXiv:1106.0522.

[34] T. Sjöstrand, S.Mrenna, P.Skands, PYTHIA6.4 physicsand manual, J.High EnergyPhys.05(2006)026,http://dx.doi.org/10.1088/1126-6708/2006/05/026, arXiv:hep-ph/0603175.

[35] J. Pumplin, D.R. Stump, J. Huston, H.-L. Lai,P. Nadolsky, W.-K. Tung, New generationofpartondistributionswithuncertaintiesfromglobalQCD analy-sis,J.HighEnergyPhys.07(2002)012,http://dx.doi.org/10.1088/1126-6708/ 2002/07/012,arXiv:hep-ph/0201195.

[36] S.Agostinelli,et al.,GEANT4,GEANT4—asimulationtoolkit,Nucl.Instrum. MethodsA506(2003)250,http://dx.doi.org/10.1016/S0168-9002(03)01368-8. [37] CMS Collaboration, Measurement of Wγ and Zγ production in pp

colli-sionsat√s=7 TeV,Phys.Lett.B701(2011)535,http://dx.doi.org/10.1016/ j.physletb.2011.06.034,arXiv:1105.2758.

[38] CMSCollaboration,CMSLuminosityBasedonPixelClusterCounting— Sum-mer2013Update,CMSPhysicsAnalysisSummaryCMS-PAS-LUM-13-001,2013, URL:http://cds.cern.ch/record/1598864.

[39]M.Guzzi,P.Nadolsky,E.Berger,H.-L.Lai,F.Olness,C.-P.Yuan,CT10parton dis-tributionsandotherdevelopmentsintheglobalQCDanalysis,arXiv:1101.0561, 2011.

[40] A.D. Martin, W.J. Stirling, R.S. Thorne, G. Watt, Parton distributions for the LHC, Eur. Phys. J. C 63 (2009) 189, http://dx.doi.org/10.1140/epjc/ s10052-009-1072-5,arXiv:0901.0002.

[41] H.-L. Lai, J. Huston, Z. Li, P. Nadolsky, J. Pumplin, D. Stump, C.P. Yuan, Uncertaintyinduced byQCD coupling in the CTEQ global analysis of par-tondistributions, Phys. Rev. D82 (2010) 054021, http://dx.doi.org/10.1103/ PhysRevD.82.054021,arXiv:1004.4624.

[42] A.L.Read,Presentationofsearchresults:theC Lstechnique,J.Phys.G28(2002)

2693,http://dx.doi.org/10.1088/0954-3899/28/10/313.

[43] T. Junk, Confidence level computation for combining searches with small statistics,Nucl.Instrum.MethodsA434(1999)435,http://dx.doi.org/10.1016/ S0168-9002(99)00498-2,arXiv:hep-ex/9902006.

[44] O.J.P. Éboli, M.C. Gonzalez-Garcia, J.K. Mizukoshi, pp → j je±μ±νν and

j je±μ∓ννato(α6

em)ando(αem4 αs2)forthestudyofthequarticelectroweak

gaugeboson vertexat CERN LHC,Phys. Rev.D 74 (2006) 073005, http:// dx.doi.org/10.1103/PhysRevD.74.073005,arXiv:hep-ph/0606118.

[45] S.S. Wilks,The large-sample distribution ofthe likelihood ratiofor testing compositehypotheses,Ann.Math.Stat.9(1938)60,http://dx.doi.org/10.1214/ aoms/1177732360.

[46] G.J. Gounaris, J. Layssac, F.M. Renard, Unitarity constraints for transverse gaugebosonsatLEPandsupercolliders,Phys.Lett.B332(1994)146,http:// dx.doi.org/10.1016/0370-2693(94)90872-9,arXiv:hep-ph/9311370.

[47]J.Baglio,J.Bellm,F.Campanario,B.Feigl,J.Frank,T.Figy,M.Kerner,L.D.Ninh, S.Palmer,M.Rauch,R.Roth,F.Schissler,O.Schlimpert,D.Zeppenfeld,Release Note—VBFNLO2.7.0,arXiv:1404.3940,2014.

TheCMSCollaboration

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. Treberer-Treberspurg,W. Waltenberger, C.-E. Wulz1

InstitutfürHochenergiephysik,Wien,Austria

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, N. Heracleous,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, C. Caillol, 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, D. Poyraz,S. Salva, R. Schöfbeck, M. Tytgat,

W. Van Driessche, E. Yazgan,N. Zaganidis

GhentUniversity,Ghent,Belgium

C. Beluffi3, O. Bondu,S. Brochet,G. Bruno, A. Caudron, L. Ceard,S. De Visscher, C. Delaere, M. Delcourt,

L. Forthomme,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 Silveira,

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

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

C.S. Moona,5,S.F. Novaesa,Sandra S. Padulaa, D. Romero Abadb, J.C. Ruiz Vargas

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

InstituteofHighEnergyPhysics,Beijing,China

Y. Ban, Q. Li, S. Liu,Y. Mao, S.J. Qian, D. Wang,Z. Xu, D. Yang,Z. Zhang

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

UniversityofSplit,FacultyofElectricalEngineering,MechanicalEngineeringandNavalArchitecture,Split,Croatia

Z. Antunovic, M. Kovac

UniversityofSplit,FacultyofScience,Split,Croatia

V. Brigljevic,D. Ferencek, K. Kadija,S. Micanovic, L. Sudic

InstituteRudjerBoskovic,Zagreb,Croatia

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

UniversityofCyprus,Nicosia,Cyprus

M. Finger8, M. Finger Jr.8

CharlesUniversity,Prague,CzechRepublic

E. Carrera Jarrin

UniversidadSanFranciscodeQuito,Quito,Ecuador

S. Elgammal9,A. Mohamed10, Y. Mohammed11,E. Salama9,12

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

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

T. Peltola,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, I.N. Naranjo, M. Nguyen,C. Ochando,

G. Ortona,P. Paganini, P. Pigard,S. Regnard, R. Salerno, Y. Sirois, T. Strebler, Y. Yilmaz,A. Zabi

LaboratoireLeprince-Ringuet,EcolePolytechnique,IN2P3-CNRS,Palaiseau,France

J.-L. Agram13,J. Andrea, A. Aubin,D. Bloch, J.-M. Brom,M. Buttignol, E.C. Chabert,N. Chanon, C. Collard,

E. Conte13,X. Coubez, J.-C. Fontaine13, D. Gelé, U. Goerlach,A.-C. Le Bihan, J.A. Merlin14, 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

A. Khvedelidze8

GeorgianTechnicalUniversity,Tbilisi,Georgia

I. Bagaturia16

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.F. Schulte,J. Schulz, T. Verlage,H. Weber, V. Zhukov15

RWTHAachenUniversity,I.PhysikalischesInstitut,Aachen,Germany

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

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

S. Mukherjee,M. Olschewski, K. Padeken,P. Papacz, T. Pook,M. Radziej, H. Reithler, M. Rieger,

F. Scheuch,L. Sonnenschein, D. Teyssier,S. Thüer

RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

V. Cherepanov, Y. Erdogan,G. Flügge, F. Hoehle, B. Kargoll, T. Kress, A. Künsken, J. Lingemann,

A. Nehrkorn, A. Nowack,I.M. Nugent, C. Pistone,O. Pooth, A. Stahl14

M. Aldaya Martin,C. Asawatangtrakuldee, I. Asin, K. Beernaert, O. Behnke,U. Behrens,A.A. Bin Anuar,

K. Borras17,A. Campbell, P. Connor, C. Contreras-Campana, F. Costanza, C. Diez Pardos,G. Dolinska,

G. Eckerlin, D. Eckstein, E. Gallo18, J. Garay Garcia, A. Geiser, A. Gizhko, J.M. Grados Luyando,

P. Gunnellini, A. Harb, J. Hauk, M. Hempel19,H. Jung,A. Kalogeropoulos,O. Karacheban19,M. Kasemann,

J. Keaveney, J. Kieseler, C. Kleinwort,I. Korol, W. Lange, A. Lelek, J. Leonard,K. Lipka, A. Lobanov,

W. Lohmann19, 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,K.D. Trippkewitz, G.P. Van Onsem, R. Walsh, C. Wissing

DeutschesElektronen-Synchrotron,Hamburg,Germany

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

M. Hoffmann, A. Junkes,R. Klanner,R. Kogler, N. Kovalchuk,T. Lapsien,T. Lenz,I. Marchesini, D. Marconi,

M. Meyer, M. Niedziela,D. Nowatschin, J. Ott, F. Pantaleo14,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

UniversityofHamburg,Hamburg,Germany

C. Barth,C. Baus, J. Berger,E. Butz, T. Chwalek, F. Colombo, W. De Boer, A. Dierlamm,S. Fink, R. Friese,

M. Giffels,A. Gilbert, D. Haitz, F. Hartmann14, S.M. Heindl,U. Husemann, I. Katkov15, P. Lobelle Pardo,

B. Maier, H. Mildner, M.U. Mozer, T. Müller,Th. Müller, M. Plagge, G. Quast, K. Rabbertz, S. Röcker,

F. Roscher,M. Schröder, 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

A. Agapitos, 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. Horvath20, F. Sikler,V. Veszpremi, G. Vesztergombi21,A.J. Zsigmond

WignerResearchCentreforPhysics,Budapest,Hungary

N. Beni, S. Czellar, J. Karancsi22,A. Makovec, J. Molnar,Z. Szillasi

InstituteofNuclearResearchATOMKI,Debrecen,Hungary

M. Bartók21,P. Raics, Z.L. Trocsanyi, B. Ujvari

InstituteofPhysics,UniversityofDebrecen,Hungary

S. Bahinipati, S. Choudhury23,P. Mal, K. Mandal, A. Nayak24, D.K. Sahoo,N. Sahoo, S.K. Swain

NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

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

R. Kumar,A. Mehta, M. Mittal, J.B. Singh, G. Walia

Ashok Kumar,A. Bhardwaj, B.C. Choudhary, R.B. Garg,S. Keshri, A. Kumar,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. Mohanty14, 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, N. Sur, B. Sutar

TataInstituteofFundamentalResearch-A,Mumbai,India

S. Banerjee, S. Bhowmik25,R.K. Dewanjee, S. Ganguly,M. Guchait, Sa. Jain, S. Kumar, M. Maity25,

G. Majumder,K. Mazumdar, B. Parida,T. Sarkar25, N. Wickramage26

TataInstituteofFundamentalResearch-B,Mumbai,India

S. Chauhan,S. Dube, A. Kapoor, K. Kothekar, A. Rane, S. Sharma

IndianInstituteofScienceEducationandResearch(IISER),Pune,India

H. Bakhshiansohi,H. Behnamian,S. Chenarani27,E. Eskandari Tadavani, S.M. Etesami27, A. Fahim28,

M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi,F. Rezaei Hosseinabadi,

B. Safarzadeh29, 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,14,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. Fasanella}a,b_{, P. Giacomelli}a_{, C. Grandi}a_{, L. Guiducci}a,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,14

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,14

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

L. Benussi, S. Bianco, F. Fabbri,D. Piccolo, F. Primavera14

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. Brianza,M.E. Dinardoa,b, S. Fiorendia,b,S. Gennaia,A. Ghezzia,b, P. Govonia,b,S. Malvezzia,

R.A. Manzonia,b,14, B. Marzocchia,b,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,14, M. Espositoa,b, F. Fabozzia,c,

A.O.M. Iorioa,b, G. Lanzaa,L. Listaa, S. Meolaa,d,14,M. Merolaa,P. Paoluccia,14, C. Sciaccaa,b, F. Thyssen

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

P. Azzia,14, 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,14, N. Pozzobona,b,P. Ronchesea,b, F. Simonettoa,b,E. Torassaa, M. Zanetti,P. Zottoa,b,A. Zucchettaa,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,30_{,P. Azzurri}a,14_{, G. Bagliesi}a_{, J. Bernardini}a_{, T. Boccali}a_{, R. Castaldi}a_{,M.A. Ciocci}a,30_, R. Dell’Orsoa,S. Donatoa,c,G. Fedi, A. Giassia, M.T. Grippoa,30, F. Ligabuea,c,T. Lomtadzea,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,G. D’imperioa,b,14,D. Del Rea,b,14,M. Diemoza,S. Gellia,b, C. Jordaa,E. Longoa,b,F. Margarolia,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,14,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, L. Fincoa,b, B. Kiania,b, C. Mariottia, S. Masellia,E. Migliorea,b, V. Monacoa,b, E. Monteila,b, 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, C. La Licataa,b, A. Schizzia,b, A. Zanettia

a_{INFNSezionediTrieste,Trieste,Italy} b_{UniversitàdiTrieste,Trieste,Italy}

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

KyungpookNationalUniversity,Daegu,RepublicofKorea

H. Kim,A. Lee

ChonbukNationalUniversity,Jeonju,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, S.B. Oh,S.h. Seo, U.K. Yang,H.D. Yoo, G.B. Yu

SeoulNationalUniversity,Seoul,RepublicofKorea

M. Choi,H. Kim, 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, D. Kim,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 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,A. Hernandez-Almada,

R. Lopez-Fernandez,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

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, W.A. Khan, 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, 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,I. Golutvin, I. Gorbunov, A. Kamenev, V. Karjavin, V. Korenkov,A. Lanev, A. Malakhov,

V. Matveev36,37, V.V. Mitsyn,P. Moisenz, V. Palichik,V. Perelygin, S. Shmatov, S. Shulha,N. Skatchkov,

V. Smirnov, E. Tikhonenko,A. Zarubin

JointInstituteforNuclearResearch,Dubna,Russia

L. Chtchipounov,V. Golovtsov, Y. Ivanov, V. Kim38, E. Kuznetsova39,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

M. Chadeeva40, M. Danilov40,O. Markin

NationalResearchNuclearUniversity‘MoscowEngineeringPhysicsInstitute’(MEPhI),Moscow,Russia

V. Andreev,M. Azarkin37, I. Dremin37,M. Kirakosyan, A. Leonidov37, S.V. Rusakov,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