Search for pair production of excited top quarks in the lepton + jets final state

Contents lists available atScienceDirect

Physics

Letters

B

www.elsevier.com/locate/physletb

Search

for

pair

production

of

excited

top

quarks

in

the

lepton

+

jets

final

state

Receivedinrevisedform16January2018 Accepted17January2018

Availableonline3February2018 Editor:M.Doser

Keywords: CMS Physics

Beyondtwogenerations Excitedtopquark

Asearchisperformedforthepairproductionofspin-3/2 excitedtopquarks,eachdecayingtoatopquark andagluon.ThesearchusesthedatacollectedwiththeCMSdetectorfromproton–protoncollisionsat acenter-of-mass energy of13 TeV,corresponding toan integratedluminosity of 35.9 fb−1.Eventsare selected byrequiring an isolatedmuon or electron, animbalance in the transverse momentum, and atleastsix jetsofwhichexactly twomustbe compatiblewith originatingfrom thefragmentationof abottom quark.No significantexcessoverthestandard model predictionsis found.Alower limitof 1.2 TeV issetat95%confidencelevelonthemassofthespin-3/2 excitedtopquarkinanextensionof the Randall–Sundrummodel,assuming a100% branchingfraction ofitsdecayintoatop quarkand a gluon.Thesearethebestlimitstodateinasearchforexcitedtopquarksandthefirstat13 TeV.

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

1. Introduction

Thestandardmodel(SM)ofparticlephysicsprovidesa success-fuldescription of the properties of the elementary particles and theirinteractions.Despiteitssuccess,theSMisassumedtobean effectivemodelofamorecompletetheory.Manyextensionsofthe SM predict that the top quark is a compositeparticle and not a fundamentalobject[1–4].Adirectconfirmationofthishypothesis couldbeachievedbythediscoveryofanexcitedtopquark(t∗).

In models that describe the proposed excited top quark [5, 6], weak isodoublets are used to represent both left- and right-handedcomponentsofthet∗ quark, allowingforadescriptionof finitemassespriortotheonsetofelectroweaksymmetrybreaking. Thus,incontrasttotheheavytopquarkfromasequential fourth-generation model, in these models the existence of t∗ quarks is notstronglyconstrainedbythediscoveryofaSM-likeHiggsboson [7–9]. In string realizations of the Randall–Sundrum (RS) model [10,11],the right-handed t∗ quark is expected to be the lightest spin-3/2 excitedstate[12].

Aspin-3/2 t∗ quark isdescribed bytheRarita–Schwinger [13] vector spinor Lagrangian. At the energy of LHC, the production crosssection ofspin-3/2 quarksis proportional tosˆ3,where ˆs is

thesquareoftheenergyintheparton–partoncollisionrestframe, ratherthan ˆs−1_{,asitisforspin-1/2 quarks[14].Therefore,when} integrating over the parton momentum fractions (x) in proton–

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

protoncollisions,spin-3/2 quarksreceiveacontributionatlarge x values that is greater than that fromspin-1/2 quarks. In the RS model,thespin-3/2 t∗ quarkisexpectedtohaveapairproduction cross sectionof theorder ofa fewpicobarns at√s=13TeV, for at∗ ofmassmt∗=1TeV[1,14,15],whichdominatesoversinglet∗ productionformostoftheparameterspaceinthemodel[12].The t∗ quark decays predominantlyto atop quark through the emis-sionofagluon[1,12,15,16].

InthisLetter, wepresentasearch forpair-producedt∗ quarks, where each t∗ quark decaysexclusively to a top quark (t)anda gluon (g). We use data recorded in 2016 with the CMS detec-tor in proton–proton (pp) collisions at √s=13TeV at the LHC, corresponding to an integratedluminosity of 35.9 fb−1. We con-sider the case where one top quark decays via a hadronically decaying W boson, and the W boson originating from the sec-ond top quark decays to an electron or muon and a neutrino: t∗t∗→ (tg)(tg)→ (Wbg)(Wbg)→ (qqbg)(νbg). We refer to the resultingfinal state(onereconstructed muonorelectron,missing transversemomentum,andmultiplejets)asthelepton+jets de-caytopology.

Asearchforpair-producedt∗ quarkswaspreviouslyperformed byCMSusingpp collisionsat√s=8TeV[17].ThisLetterpresents amoresensitivesearchbecauseofthehighercollisionenergyand thereforelarger signal crosssections,andthelarger datasample, whichisnearlytwicethesize.Inaddition,thesimulationhasbeen improvedby explicitlyincludingthe Rarita–SchwingerLagrangian inthe generator,resultingin thecorrectspin correlationsforthe signal.

https://doi.org/10.1016/j.physletb.2018.01.049

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

2. The CMS detector and simulated samples

The central feature of the CMS apparatus is a superconduct-ing solenoidof 6 m internal diameter, providinga magnetic field of3.8 T. Withinthe solenoidvolume area siliconpixel andstrip tracker,aleadtungstatecrystalelectromagneticcalorimeter(ECAL), andabrass andscintillatorhadroncalorimeter(HCAL),each com-posedof abarrel andtwo endcapsections.Forwardcalorimeters extendthepseudorapidity(η)coverageprovidedbythebarreland endcap detectors. Muons are measured in gas-ionization detec-torsembedded inthesteelflux-return yokeoutsidethesolenoid. A moredetaileddescription oftheCMSdetector,together witha definition of the coordinate system used and the relevant kine-maticvariables,canbefoundinRef.[18].

Simulated t∗t∗ signal events are generated in 100 GeV steps with mt∗ in the range 700–1600 GeV, using the MadGraph5_ amc@nlo [19] event generator and NNPDF3.0 [20] for the par-ton distribution functions (PDFs). The t∗t∗ production cross sec-tionrangesfrom≈5 pb atmt∗=700GeV,downto≈4 fb atmt∗= 1600GeV.Thiscrosssection iscalculatedatleading orderin per-turbationtheory,withthefactorizationandrenormalizationscales setto mt∗; thecalculation is cut offat 7mt∗ toprevent unitarity violation. TheRarita–Schwinger Lagrangian,included inthe Mad-Graph 5 generator, is used for simulating spin-3/2 t∗t∗ events. Thisimplementationandthecorrespondingphysicsparametersare providedbytheauthorsofRef.[14].Thewidthofthet∗ quark is assumedtobe10 GeV, whichismuchnarrowerthanthedetector resolution. Parton shower andhadronization processes are mod-eled using pythia 8.212[21].The generatedeventsare processed through asimulation ofthe CMSdetectorbased on Geant4[22], andarereconstructedusingthesamealgorithmsasusedfordata. We estimate SM backgrounds using a data-derived approach. SimulatedsamplesforSMprocessesareusedtostudythe model-ingofthebackgroundandtoprovideacross-checkoftheanalysis procedures. The simulated SM samples relevant to this analysis are: tt production;single topquark productionvia thes-channel, t-channel,andtWprocesses;W and Z boson productionin asso-ciationwithjets;thett+W, tt+H,andtt+Z processes.Thett and tt+H processesaresimulatedusing powheg 2.0[23–27],whilethe otherSM processesare simulatedusing MadGraph5_amc@nlo up tonext-to-leadingorder[19,28,29].Allsimulatedsamplesinclude theadditionalcontributionsfromoverlappingpp collisionswithin the same and nearby bunch crossings (“pileup”) at large instan-taneousluminosity.Simulatedeventsaregivenindividualweights tomatchthedistributionoftheaveragenumberofpileup interac-tionsindata.

3. Event reconstruction

EventreconstructionisbasedontheCMSparticle-flow(PF) al-gorithm[30],whichtakesintoaccountinformationfromall subde-tectors,includingmeasurementsfromthetrackingsystem, energy deposits in the ECAL and HCAL, and tracks reconstructed in the muon detectors.Giventhisinformation,all particles inthe event are reconstructed as electrons, muons, photons, and charged or neutralhadrons.PhotonsareidentifiedasECALenergyclustersnot linkedtotheextrapolationofanycharged-particletrajectorytothe ECAL.Muonsareidentifiedasatrackinthecentraltracker consis-tent witheither atrack orseveralhits inthe muon system, and not associatedwithenergyclustersin thecalorimeters.Electrons areidentifiedasaprimarychargedparticletrackthatextrapolates to atleastone ECAL energycluster. The trackmaybe associated withbremsstrahlungphotonsemitted alongthe waythroughthe trackermaterial.Chargedhadronsareidentifiedascharged-particle tracksneitheridentifiedaselectrons,norasmuons.Finally,neutral

hadrons areidentified asHCAL energyclustersnot linked to any charged-hadron trajectory, orto ECAL and HCAL energyexcesses withrespecttotheexpectedchargedhadronenergydeposits.

Foreachevent,jetsfromthesereconstructedparticlesare clus-tered withthe infrared andcollinear safeanti-kT algorithm [31], using a distance parameter R=0.4. Charged hadrons associated withpileup verticesareexcluded fromjet reconstruction.The jet momentum isthe vectorial sum ofthe momenta ofall particles containedinthejet.Thereconstructedjetmomentumisfoundin simulationtobewithin 5to10%ofthetruemomentumoverthe whole pTspectrumanddetectoracceptance.Jetenergycorrections are derived from the simulation and measurements in collision data [32]. The jet energy resolution amounts typically to 15% at 10 GeV, 8%at100 GeV, and4% at1 TeV[32].The jetenergy reso-lutioninsimulationisdegradedtomatchthatobservedindata.

Jetsare identifiedasoriginatingfromabottom quark through a combined secondary vertexalgorithm CSVv2 [33,34].The algo-rithmusesamultivariatediscriminatortocombineinformationon the significance ofthe impact parameter, the jet kinematics,and the locationof thesecondary vertex.A workingpointof the dis-criminator with ≈70% b quark identification efficiency and ≈1% mistagefficiencyforlight quarksandgluonsis usedinthis anal-ysis. Small differences in b tagging efficiencies and mistag rates betweendataandsimulatedeventsareaccountedforbyapplying additionalcorrectionstosimulation.

Themissingtransversemomentumvectorisdefinedasthe neg-ativevectorsumofthemomentaofallreconstructedPFcandidates inan eventprojected ontotheplaneperpendicular tothebeams. Itsmagnitudeisreferredtoaspmiss

T .

4. Event selection

Thisanalysissearchesfort∗t∗production,witheacht∗decaying to t+g and thett pairintheeventreconstructedinthelepton+ jetsfinalstate.Eventsarerequiredtocontainexactlyone isolated lepton, pmiss

T , andatleastsixjets, exactlytwo of whichmust be b tagged.

Eventscontainingamuonareselectedwithasingle-muon trig-gerthatrequiresthepresenceofanisolatedmuonwithtransverse momentum pT>27GeV. Events containing an electron are se-lected withasingle-electrontriggerthat requiresthepresenceof anisolatedelectronwithpT>32GeV.Thebackgroundrateforthe single electrontriggerwasmuch higherthanforthesingle muon trigger, requiringmorestringentselection criteriafortheelectron channel.Adeterministicannealingalgorithmisusedtoreconstruct the candidate primary vertices [35]; the vertex withthe highest trackmultiplicityisselectedastheprimary eventvertex.Selected eventsarerequiredtohavethisprimaryvertexwithin2 cm ofthe center ofthe detector inthe x– y plane, andwithin 24 cm along thez-direction.

Offline,muonsarerequiredtohave pT>30GeV and |η|<2.1. The trackassociatedwitha muon isrequired tohavehitsin the pixel and muon detectors,a good quality fit, andtransverse and longitudinalimpactparameterswithrespecttotheprimaryvertex smallerthan2and5 mm,respectively.Anisolation factorI is de-fined asthescalarsum, dividedby themuon pT,ofthe pT ofall photons, chargedhadrons,andneutralhadronswithinan angular cone of R≡(η)2_{+ (φ)}2_{<0.4 (where φ is theazimuthal} angle)aroundthetrack,correctedfortheeffectsofpileup[36].An isolationselectionI<0.15,correspondingtoanefficiencyof≈95% isused.

ElectronsarerequiredtohavepT>35GeV andtobewithinthe region|η|<2.1.Electronswithin1.44<|η|<1.56,corresponding to theECALbarrel–endcaptransitionregion,arerejectedtoavoid poor reconstruction performance. Electrons are selected using a

Table 1

Expectednumbersofselectedeventsforthesimulatedsignalprocessasa func-tionofmt∗.AlsoshownaretheexpectednumbersofeventspredictedbytheSM, togetherwith thesystematicuncertaintiesdiscussedinSection7andthe uncer-taintiesinthecrosssectionsofthevariousprocesses,aswellasthenumbersof selectedeventsobservedindata.

μ+jet final state e+jet final state t∗t∗signal, mt∗ 700 GeV 3670 2730 800 GeV 1230 1010 900 GeV 483 369 1000 GeV 200 148 1100 GeV 92 69 1200 GeV 40 29 1300 GeV 20 15 1400 GeV 9 7 1500 GeV 4 4 1600 GeV 2 2 SM processes (4.66±0.38)×104 _{(3.07±0.23)×10}4 Data 44 573 28 942

cutoff-basedselectionmethod[37]basedontheshowershape,the trackquality,thespatialmatchbetweenthetrackandthe electro-magneticcluster, thefractionoftotalcluster energyintheHCAL, andtheresulting levelof activityinthe surroundingtracker and calorimeterregions. Thecriteria imposed intheseelectron selec-tionalgorithmshaveacombinedefficiencyof≈70%.

Inadditiontotheselectionsabove,theleptonsarerequiredto havean angularseparation R<0.1 withrespect to the lepton reconstructedbythetriggersystem. Theleptonselection efficien-ciesfordataandsimulationaremeasuredusingthetag-and-probe method [37]. Additional corrections are applied to simulation to account forobserved differencesinthe efficiencies betweendata andsimulation.

The pmiss_T isrequiredtobe greaterthan20GeV,whilethejets arerequiredtohavepT>30GeV,|η|<2.4,andangularseparation R>0.4 with respect to well-identified electrons ormuons. In orderto reject misreconstructed, poorly reconstructed, and noisy jets,thefractional energycontributionfrombothECALandHCAL mustbenon-zeroandnon-unity. Exactlytwo jetsarerequiredto passtheb taggingcriteria.

The expected yields after event selection are summarized in Table 1. Simulated signal events pass the selection criteriawith acceptance times efficiency of 1.4–2.2%, depending on the chan-nelandonthesignal mass.Aftertheapplicationofall selections, 44573 events are observed in the μ + jetschannel and 28942 eventsinthee+jetschannel.Theyieldspredictedfromthe sim-ulatedSMbackgroundprocessesare46600 eventsinthe μ+jets channeland30700 eventsinthee+jetschannel.

Small differences between data and the SM predictions are within the estimated uncertainties of the simulation, with the dominantuncertaintybeingthechoiceoftherenormalizationand factorizationscalesusedinthegeneratorofthett events.Detailsof theuncertaintiesaregiveninSection7.Furthermore,the differen-tialdistributionsofkinematicvariablesofsimulatedSMprocesses arealsoinagreementwithdata,asshowninFig. 1.Inparticular, thedistributionofthe invariant massofa t + jetsystem(mt+jet, seeSection 5 fordetails) indata isin agreement withthe back-groundestimation.

5. Mass reconstruction

SincethedominantbackgroundisSMtt productionwithextra jets,thereconstructedinvariantmassspectrumofthet+jet sys-temsisusedtodistinguishbetweent∗t∗signalandtt background. The pmiss

T isassumedto becarriedaway entirelybytheneutrino

from theleptonically decaying W boson (Wlep). We assume that the parent W boson is on shell andthe neutrino is massless in ordertodeterminethelongitudinalmomentumoftheneutrino.

Giventhehighjetmultiplicityoftheeventselection,ameasure was designed for evaluating different associations of the recon-structedjetswiththepartonobjectsinthefinalstate.Forthejets, the sixjetswiththe highest pT values are takeninto considera-tion.Theb taggedjetsareassignedtooneoftheb quarkpartons, andtheotherjetsareassociatedwiththedecaydaughtersofthe hadronicallydecayingW (Whad)orwiththegluonsfromt∗ decay. Thequalityofthejet-partonassignmentforasingleeventis evalu-atedwithan S valuebasedonhowwelltheintermediatephysical objectsarereconstructed:

S=  mqq−mW σW 2 + _m qqb−mt σt,had 2 +  mνlb−mt σt,lep 2 +  mqqbg−mνlbg σt∗ 2 , (1)

where mqq is the invariant mass of the jets assigned to Whad daughters. Invariant masses of the physical objects assigned to hadronically and leptonically decaying t (t∗) quarks are denoted bymqqb (mqqbg) andmνlb (mqqbg), respectively.mW andmt are themass oftheW bosonandtop quark recordedbythe particle datagroup [38],being80.4and173.34 GeV, respectively.The ex-pecteddetectorresolutionsoftheintermediateparticles σW, σt,had,

σt,lepand σt∗ areestimatedtobe24,34,30,and230 GeV, respec-tively.Theseestimates areobtainedby reconstructing thet∗t∗, tt andWhad inthedecaytopologyusingthetruthinformationfrom simulatedsignal samples.Additionalstudies haveshownthatthe massreconstructionisinsensitivetochangesinthedetector reso-lutionvalues.

Thejet-partonassignmentwiththesmallestS valueistakento representthe decay topology ofa single event, underthe t∗ hy-pothesis.Theaveragevalueofthemqqbg andmνlbg computedfor thisassignmentistakentorepresentthereconstructedt∗ massof anevent,notatedasmt+jet.Therateatwhichallsixjetsareall cor-rectly assignedis around11%, withthe maindifficulty being the correctassignmentofthejetsfromthehadronicallydecaying W.

6. Background modeling

Todeterminethepresenceofsignaleventsindata,anunbinned extended maximum likelihood fit of a signal-plus-background modelisperformedonthemt+jet>400GeV spectrum.

Themasstemplateofthet∗t∗signalisconstructedby smooth-ingthemassdistributionfromsimulations,usinganadaptive ker-nel estimation [39] with a Gaussian kernel and withno restric-tionontheboundary.Thesmoothnessparameter ρ introducedin Ref. [39] isdetermined by the square rootof the standard devi-ation ofthesignal distributionoverthe subsetwith≥4 correctly assignedpartons.

The background distribution is modeled using a log-normal function(uptoanormalizationfactor):

fbkg(m)= 1 m√2π exp  −a2ln2  m m0  , (2)

wherem isthemass,anda2andm0aretheparametersthat deter-minetheshapeofthebackground.Duringthefittotheobserved data,thenumber ofbackgroundevents,aswellasthe shape pa-rametersofthebackgroundfunction,arefreeparameters.

Toverifywhetherthefitissensitivetothepresenceoft∗t∗ sig-nal,apseudo-datasetisgeneratedwiththemt+jetspectrumofthe simulatedbackgroundsandtheninjectedwiththeexpectedmt+jet

Fig. 1. Kinematic distributionsofselectedeventswithasingleleptonandsixormorejetsofwhichexactlytwoareb tagged.Dataevents(points),simulatedbackground processes(stackedhistograms),andasimulated800 GeV signalprocess(dashedline)areshown.Eventsselectedintheμ+jetfinalstateareshownontheleftwhilethose inthee+jetfinalstateareshownontheright.Fromuppertolower,thekinematicvariablesdisplayedaretheleptonpT,thejetpTandthemt+jet.Theshadedregionisthe totaluncertaintyofthesimulatedbackgroundprocesses,whichincludesstatisticalandsystematicuncertainties.(Forinterpretationofthereferencestocolorinthisfigure, thereaderisreferredtothewebversionofthisarticle.)

signalspectrumforvarioushypothesesofthesignalcrosssection. Performing the same fit over multiple sets of pseudo-data with varyingsignalcrosssectionsshowednoevidenceofbias.

To ensure that the log-normal function is sufficient to model thebackground,a likelihoodratiotestisconductedbycomparing theresultsoffittingthespectrumofthesimulatedSMbackground toanextendedlog-normalfunctionsoftheform:

fbkg,N(m)= 1 m√2π exp  −a2ln2  m m0  −a3ln3  m m0  − . . . −aNlnN  m m0  . (3)

Increasing the number of parameters does not improve the de-scriptionofthebackground.

Theresultsofthefitperformedondatawiththe800 GeV signal spectrumareshowninFig. 2.Thedistributionofeventsindatais in agreementwitha nullhypothesis. Based onthe resultsof the Kolmogorov–Smirnovtests,thesignal+backgroundmodelandthe background-onlymodelbothyieldgoodfitstothedata.

7. Systematic uncertainties

The impact of experimental and theoretical sources of uncer-taintiesisconsideredandsummarizedinTable 2.Foreachsource

Fig. 2. The mt+jetspectrumfordata(points),thesignal+backgroundfit(green),thebackgroundcomponentofthesignal+backgroundfit(blue),andtheexpectedspectrum forasimulated800 GeV signalprocess(red dashed)normalizedtotheintegrated luminosityofdata.Since thereisnosignificantexcessofsignalfoundindata, the signal+backgroundcurveoverlapsthe background-onlycomponent.The distributionsfortheμ +jetsdataareshown ontheleftwhilethosefor e+jetsdataare shownontheright.TheprobabilitiesoftheKolmogorov–Smirnovtestbetweenthedataversusthesignal+backgroundmodelandbetweenthedataversusthebackground componentaredenotedbyKallandKbkg,respectively.(Forinterpretationofthereferencestocolorinthisfigurelegend,thereaderisreferredtothewebversionofthis article.)

Table 2

Sourcesofsystematicuncertaintiesandthemethodsusedtoevaluatetheireffect onthesimulatedsignalsample.

Source of uncertainty Implementation on simulated signal sample Integrated luminosity Normalization shift by±2.5%

Statistical uncertainty Normalization shift by±1 s.d. Jet correction Correction factor varied by±1 s.d. Jet resolution Jet resolution shift by±1 s.d. b tagging SF SF varied by±1 s.d. Lepton efficiency SF SF varied by±1 s.d.

Pileup pp inelastic cross section shifted by±4.6%[41]

Modeling Smoothing parameterρvaried over range[1.17,1.66] PDF uncertainty Generator parameter varied by±1 s.d.

Scale uncertainty Generator parameter varied by±1 s.d. s.d.:standarddeviation,SF:correctionscalefactor.

ofuncertainty, alternative templates for thedistribution of mt+jet aregeneratedbyadjustingtherelevantparameters inthe simula-tion.

The uncertainties in the jet energy scale and jet resolutions depend on the pT and η of the jets. Alternative mass templates aregeneratedbyrescalingthenominaljetfour-momentuminthe simulationby±1 standarddeviation(s.d.)oftheassociated uncer-taintiesinenergyscaleandresolution.Suchuncertaintiesarealso coherentlypropagatedto all observables,including pmiss_T .Varying the jet energy used forreconstruction has<0.1% impact on the signalacceptance.

The b tagging and lepton selection scale factors for residual differencesbetweendataandsimulationhavetheirrespective sys-tematicandstatisticaluncertainties.Alternativetemplatesare gen-eratedbyshiftingthe correctionscalefactorsby ±1 s.d. fortheir respectiveuncertainties.Onaverage,theb taggingscalefactorand lepton scalefactors affect the signal acceptanceby 2.8 and2.5%, respectively.

Becauseofuncertaintiesinthe totalinelasticpp crosssection, whencalculating the data pileup scenario alternative pileup cor-rectionsaremadewiththeinelasticcrosssectionscaledby±1 s.d. Variationsinthepileupcorrectionshaveanaverageimpactonthe signalacceptanceof0.7%.Thenumberofsignal eventsisalso af-fectedby the uncertainty on the integrated luminosity,which is knowntoaprecisionof2.5%[40].

The theoretical uncertainties considered are those associated withthe choice of the PDF, andthe renormalization and factor-izationscalesusedbytheeventgenerator.Theeffectsofthe

theo-retical uncertaintiesareobtainedbychangingthevarious genera-torparameterswithintheirestimateduncertaintiesandgenerating newmt+jetfittemplatesthatareusedtocalculatenewsensitivities. In addition to the statisticaluncertainty originating fromthe signal+backgroundfit,systematicuncertaintiesareintroducedto coverthechoiceofmodeling.Alternativesignaltemplatesare gen-erated withdifferent choicesof ρ by changing the subset to re-quire≥3 and≥5 correctlyassignedpartons.Thebackgroundshape isdeterminedfromdata.Simulatedeventswithdifferent configu-rations,aswellasseveralalternativemodelshavebeentested.The chosen model, with the parameters floated in the limit compu-tation, has proven to describe the dataand cover theassociated systematicuncertaintiessufficientlywell.

8. Statistical analysis and extraction of limits

No excessaboveSM backgroundisobserved.Wesetan upper bound on the t∗t∗ production cross section usingthe asymptotic modified frequentist CLs criterion [42–45]. The null hypothesis likelihoodfunctionistakenfromthebackgroundcomponentofthe signal+backgroundfitdescribedinSection6.Fortheuncertainties describedinSection7,ajointtemplateisused,wherethenominal template islinearly interpolatedto thetemplates generatedwith therelevantparametersshiftedby ±1 standarddeviation.Eachof theinterpolationvariablesistakenasanuisanceparameterwitha standardGaussianprior.

Thefitisperformedseparatelyinthemuonandelectron chan-nels, andthe resultsofboth are usedto obtain combinedlimits. Fig. 3showstheobservedandexpectedupperlimitsat95% confi-dencelevelfortheproductofthet∗t∗productioncrosssectionand thesquareofthebranchingfraction,asafunctionofthet∗ mass. The lowerlimit formt∗ isgivenbythe valueatwhich theupper limit intersects with the theoretical cross section from Ref. [14]. Both theobservedandexpectedlower limitsofmt∗ forthe com-binedmuonandelectrondataare1.2 TeV,withinuncertainties.

9. Summary

A search has been conducted forpair production of spin-3/2 excited top quarks t∗ inproton–protoninteractions, witheach t∗ decaying exclusivelyto a standard modeltop quark and agluon. Eventsthathaveasinglemuonorelectronandatleastsixjets, ex-actlytwoofwhichmustbeidentifiedasoriginatingfromabottom

Fig. 3. The expectedandobserved95%confidencelevelupperlimitsfortheproduct oftheproductioncrosssectionoft∗t∗andthesquareofthebranchingfraction,as afunctionofthet∗mass,forthecombinedlepton+jetsanalysis.Thetheoretical productioncrosssectionassuminga100%t∗→tg branchingfractionisshownalong withitsuncertainties,describedinSection7.(Forinterpretationofthereferences tocolorinthisfigure,thereaderisreferredtothewebversionofthisarticle.) quark,areselectedfortheanalysis.Assumingt∗t∗ production,the final-state objects are associated withthe t∗ candidates in each event. No significant deviations fromstandard model predictions are observed inthe t + jet system, and an upperlimit is set at 95%confidence levelonthepairproduction crosssectionof t∗t∗, asafunctionofthet∗ mass.Interpretingtheresultsinthe frame-workofaspin-3/2 t∗ model,assuminga100% branchingfraction ofitsdecayintoatopquarkandagluon,t∗ massesbelow1.2 TeV are excluded. These are the best limits to date on the mass of spin-3/2 excitedtopquarksandthefirstat13 TeV.

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,wegratefullyacknowledgethecomputingcentresand personneloftheWorldwideLHCComputingGridfordeliveringso effectivelythe computinginfrastructureessential to ouranalyses. Finally, we acknowledge the enduring support for the construc-tionandoperation oftheLHCandthe CMSdetectorprovidedby thefollowingfundingagencies:BMWFWandFWF(Austria);FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MOST, and NSFC (China); COLCIEN-CIAS(Colombia);MSESandCSF(Croatia);RPF(Cyprus);SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of Fin-land,MEC,andHIP(Finland);CEAandCNRS/IN2P3(France);BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hun-gary);DAEandDST(India);IPM(Iran);SFI(Ireland);INFN(Italy); MSIPandNRF(RepublicofKorea);LAS (Lithuania);MOE andUM (Malaysia); BUAP, CINVESTAV,CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland);FCT(Portugal);JINR(Dubna);MON,ROSATOM, RAS,and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand);TUBITAK and TAEK (Turkey);NASU andSFFR(Ukraine);STFC(UnitedKingdom);DOEandNSF(USA).

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The CMS Collaboration

A.M. Sirunyan,A. Tumasyan

YerevanPhysicsInstitute,Yerevan,Armenia

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

A. Escalante Del Valle,M. Flechl, M. Friedl,R. Frühwirth1,V.M. Ghete, J. Grossmann, J. Hrubec,

M. Jeitler1,A. König, N. Krammer, I. Krätschmer,D. Liko, T. Madlener, I. Mikulec,E. Pree, N. Rad,

H. Rohringer,J. Schieck1, R. Schöfbeck, M. Spanring, D. Spitzbart,W. Waltenberger, J. Wittmann,

C.-E. Wulz1,M. Zarucki

InstitutfürHochenergiephysik,Wien,Austria

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

InstituteforNuclearProblems,Minsk,Belarus

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

P. Van Mechelen,N. Van Remortel

UniversiteitAntwerpen,Antwerpen,Belgium

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

S. Lowette,I. Marchesini, S. Moortgat, L. Moreels,Q. Python, K. Skovpen, S. Tavernier,W. Van Doninck,

P. Van Mulders,I. Van Parijs

VrijeUniversiteitBrussel,Brussel,Belgium

D. Beghin,B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker,H. Delannoy, B. Dorney, G. Fasanella,L. Favart,

R. Goldouzian, A. Grebenyuk,A.K. Kalsi,T. Lenzi, J. Luetic, T. Maerschalk,A. Marinov, T. Seva, E. Starling,

C. Vander Velde, P. Vanlaer,D. Vannerom, R. Yonamine,F. Zenoni, F. Zhang2

UniversitéLibredeBruxelles,Bruxelles,Belgium

T. Cornelis,D. Dobur, A. Fagot,M. Gul, I. Khvastunov3,D. Poyraz, C. Roskas, S. Salva, M. Tytgat,

W. Verbeke,N. Zaganidis

H. Bakhshiansohi,O. Bondu, S. Brochet,G. Bruno, C. Caputo, A. Caudron, P. David, S. De Visscher,

C. Delaere, M. Delcourt, B. Francois,A. Giammanco, M. Komm, G. Krintiras,V. Lemaitre, A. Magitteri,

A. Mertens, M. Musich, K. Piotrzkowski,L. Quertenmont, A. Saggio, M. Vidal Marono, S. Wertz,J. Zobec

UniversitéCatholiquedeLouvain,Louvain-la-Neuve,Belgium

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

P. Rebello Teles

CentroBrasileirodePesquisasFisicas,RiodeJaneiro,Brazil

E. Belchior Batista Das Chagas, W. Carvalho,J. Chinellato4,E. Coelho, E.M. Da Costa, G.G. Da Silveira5,

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

C. Mora Herrera,L. Mundim, H. Nogima,L.J. Sanchez Rosas, A. Santoro,A. Sznajder, M. Thiel,

E.J. Tonelli Manganote4,F. Torres Da Silva De Araujo, A. Vilela Pereira

UniversidadedoEstadodoRiodeJaneiro,RiodeJaneiro,Brazil

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

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

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

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

InstituteforNuclearResearchandNuclearEnergy,BulgarianAcademyof Sciences,Sofia,Bulgaria

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

UniversityofSofia,Sofia,Bulgaria

W. Fang6, X. Gao6,L. Yuan

BeihangUniversity,Beijing,China

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

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

InstituteofHighEnergyPhysics,Beijing,China

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

StateKeyLaboratoryofNuclearPhysicsandTechnology,PekingUniversity,Beijing,China

Y. Wang

TsinghuaUniversity,Beijing,China

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

M.A. Segura Delgado

UniversidaddeLosAndes,Bogota,Colombia

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

UniversityofSplit,FacultyofElectricalEngineering,MechanicalEngineeringandNavalArchitecture,Split,Croatia

Z. Antunovic, M. Kovac

UniversityofSplit,FacultyofScience,Split,Croatia

V. Brigljevic,D. Ferencek, K. Kadija,B. Mesic, A. Starodumov7, T. Susa

M.W. Ather,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

E. El-khateeb9,S. Elgammal10,A. Mohamed11

AcademyofScientificResearchandTechnologyoftheArabRepublicofEgypt,EgyptianNetworkofHighEnergyPhysics,Cairo,Egypt

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

NationalInstituteofChemicalPhysicsandBiophysics,Tallinn,Estonia

P. Eerola,H. Kirschenmann, J. Pekkanen,M. Voutilainen

DepartmentofPhysics,UniversityofHelsinki,Helsinki,Finland

J. Havukainen, J.K. Heikkilä, T. Järvinen,V. Karimäki, R. Kinnunen, T. Lampén, K. Lassila-Perini,S. Laurila,

S. Lehti,T. Lindén, P. Luukka, H. Siikonen, E. Tuominen, J. Tuominiemi

HelsinkiInstituteofPhysics,Helsinki,Finland

T. Tuuva

LappeenrantaUniversityofTechnology,Lappeenranta,Finland

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

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

J. Rander,A. Rosowsky, M.Ö. Sahin, M. Titov

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

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

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

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

A. Zabi,A. Zghiche

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

J.-L. Agram12,J. Andrea, D. Bloch,J.-M. Brom, M. Buttignol,E.C. Chabert, N. Chanon, C. Collard,

E. Conte12,X. Coubez, J.-C. Fontaine12, D. Gelé, U. Goerlach,M. Jansová, A.-C. Le Bihan, N. Tonon,

P. Van Hove

UniversitédeStrasbourg,CNRS,IPHCUMR7178,F-67000Strasbourg,France

S. Gadrat

CentredeCalculdel’InstitutNationaldePhysiqueNucleaireetdePhysiquedesParticules,CNRS/IN2P3,Villeurbanne,France

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

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

A.L. Pequegnot, S. Perries,A. Popov13,V. Sordini, M. Vander Donckt, S. Viret

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

T. Toriashvili14

Z. Tsamalaidze8

TbilisiStateUniversity,Tbilisi,Georgia

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

M. Teroerde,V. Zhukov13

RWTHAachenUniversity,I.PhysikalischesInstitut,Aachen,Germany

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

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

S. Mukherjee,T. Pook, M. Radziej, H. Reithler,M. Rieger, F. Scheuch,D. Teyssier, S. Thüer

RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

G. Flügge, B. Kargoll, T. Kress, A. Künsken, T. Müller,A. Nehrkorn, A. Nowack, C. Pistone,O. Pooth,

A. Stahl15

RWTHAachenUniversity,III.PhysikalischesInstitutB,Aachen,Germany

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

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

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

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

A. Harb,J. Hauk, M. Hempel18,H. Jung,M. Kasemann, J. Keaveney, C. Kleinwort,I. Korol, D. Krücker,

W. Lange, A. Lelek, T. Lenz,J. Leonard, K. Lipka,W. Lohmann18, R. Mankel, I.-A. Melzer-Pellmann,

A.B. Meyer, G. Mittag, J. Mnich, A. Mussgiller, E. Ntomari,D. Pitzl, A. Raspereza,M. Savitskyi, P. Saxena,

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

DeutschesElektronen-Synchrotron,Hamburg,Germany

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

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

D. Marconi,M. Meyer, M. Niedziela, D. Nowatschin, F. Pantaleo15, T. Peiffer, A. Perieanu,C. Scharf,

P. Schleper, A. Schmidt, S. Schumann,J. Schwandt, J. Sonneveld,H. Stadie,G. Steinbrück, F.M. Stober,

M. Stöver, H. Tholen, D. Troendle,E. Usai, A. Vanhoefer, B. Vormwald

UniversityofHamburg,Hamburg,Germany

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

A. Dierlamm, N. Faltermann,B. Freund, R. Friese,M. Giffels,M.A. Harrendorf, F. Hartmann15,

S.M. Heindl,U. Husemann, F. Kassel15,S. Kudella, H. Mildner, M.U. Mozer, Th. Müller, M. Plagge,

G. Quast, K. Rabbertz,M. Schröder, I. Shvetsov, G. Sieber,H.J. Simonis, R. Ulrich, S. Wayand, M. Weber,

T. Weiler, S. Williamson,C. Wöhrmann, R. Wolf

InstitutfürExperimentelleKernphysik,Karlsruhe,Germany

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

InstituteofNuclearandParticlePhysics(INPP),NCSRDemokritos,AghiaParaskevi,Greece

G. Karathanasis,S. Kesisoglou, A. Panagiotou, N. Saoulidou

NationalandKapodistrianUniversityofAthens,Athens,Greece

K. Kousouris

I. Evangelou,C. Foudas, P. Gianneios, P. Katsoulis, P. Kokkas, S. Mallios,N. Manthos, I. Papadopoulos,

E. Paradas, J. Strologas,F.A. Triantis, D. Tsitsonis

UniversityofIoánnina,Ioánnina,Greece

M. Csanad,N. Filipovic, G. Pasztor,O. Surányi, G.I. Veres19

MTA-ELTELendületCMSParticleandNuclearPhysicsGroup,EötvösLorándUniversity,Budapest,Hungary

G. Bencze,C. Hajdu, D. Horvath20, Á. Hunyadi, F. Sikler,V. Veszpremi

WignerResearchCentreforPhysics,Budapest,Hungary

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

InstituteofNuclearResearchATOMKI,Debrecen,Hungary

M. Bartók19,P. Raics, Z.L. Trocsanyi, B. Ujvari

InstituteofPhysics,UniversityofDebrecen,Debrecen,Hungary

S. Choudhury,J.R. Komaragiri

IndianInstituteofScience(IISc),Bangalore,India

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

NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

S. Bansal,S.B. Beri, V. Bhatnagar, R. Chawla, N. Dhingra,A. Kaur, M. Kaur, S. Kaur,R. Kumar, P. Kumari,

A. Mehta,J.B. Singh, G. Walia

PanjabUniversity,Chandigarh,India

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

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

UniversityofDelhi,Delhi,India

R. Bhardwaj,R. Bhattacharya, S. Bhattacharya, U. Bhawandeep, S. Dey,S. Dutt, S. Dutta, S. Ghosh,

N. Majumdar, A. Modak, K. Mondal, S. Mukhopadhyay, S. Nandan,A. Purohit, A. Roy, S. Roy Chowdhury,

S. Sarkar,M. Sharan, S. Thakur

SahaInstituteofNuclearPhysics,HBNI,Kolkata,India

P.K. Behera

IndianInstituteofTechnologyMadras,Madras,India

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

BhabhaAtomicResearchCentre,Mumbai,India

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

TataInstituteofFundamentalResearch-A,Mumbai,India

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

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

TataInstituteofFundamentalResearch-B,Mumbai,India

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

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

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

InstituteforResearchinFundamentalSciences(IPM),Tehran,Iran

M. Felcini,M. Grunewald

UniversityCollegeDublin,Dublin,Ireland

M. Abbresciaa,b, C. Calabriaa,b,A. Colaleoa,D. Creanzaa,c, L. Cristellaa,b,N. De Filippisa,c,

M. De Palmaa,b, F. Erricoa,b, L. Fiorea, G. Iasellia,c, S. Lezkia,b, G. Maggia,c,M. Maggia, G. Minielloa,b, S. Mya,b, S. Nuzzoa,b,A. Pompilia,b,G. Pugliesea,c, R. Radognaa,A. Ranieria, G. Selvaggia,b, A. Sharmaa, L. Silvestrisa,15,R. Vendittia,P. Verwilligena

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

G. Abbiendia,C. Battilanaa,b,D. Bonacorsia,b,L. Borgonovia,b,S. Braibant-Giacomellia,b,

R. Campaninia,b, P. Capiluppia,b,A. Castroa,b,F.R. Cavalloa, S.S. Chhibraa,G. Codispotia,b,M. Cuffiania,b, G.M. Dallavallea,F. Fabbria, A. Fanfania,b, D. Fasanellaa,b,P. Giacomellia,C. Grandia,L. Guiduccia,b, S. Marcellinia, G. Masettia, A. Montanaria, F.L. Navarriaa,b,A. Perrottaa, A.M. Rossia,b,T. Rovellia,b, G.P. Sirolia,b,N. Tosia

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

S. Albergoa,b,S. Costaa,b,A. Di Mattiaa,F. Giordanoa,b,R. Potenzaa,b,A. Tricomia,b,C. Tuvea,b

a_{INFNSezionediCatania,Catania,Italy} b_{UniversitàdiCatania,Catania,Italy}

G. Barbaglia, K. Chatterjeea,b,V. Ciullia,b,C. Civininia, R. D’Alessandroa,b, E. Focardia,b,P. Lenzia,b,

M. Meschinia, S. Paolettia,L. Russoa,29, G. Sguazzonia, D. Stroma, L. Viliania

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

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

INFNLaboratoriNazionalidiFrascati,Frascati,Italy

V. Calvellia,b, F. Ferroa, F. Raveraa,b,E. Robuttia,S. Tosia,b

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

A. Benagliaa, A. Beschib, L. Brianzaa,b, F. Brivioa,b, V. Cirioloa,b,15,M.E. Dinardoa,b,S. Fiorendia,b, S. Gennaia, A. Ghezzia,b,P. Govonia,b, M. Malbertia,b,S. Malvezzia,R.A. Manzonia,b, D. Menascea, L. Moronia,M. Paganonia,b, K. Pauwelsa,b, D. Pedrinia,S. Pigazzinia,b,30, S. Ragazzia,b,

T. Tabarelli de Fatisa,b

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

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

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

P. Azzia,L. Benatoa,b, D. Biselloa,b, A. Bolettia,b, R. Carlina,b, A. Carvalho Antunes De Oliveiraa,b,

S. Lacapraraa,P. Lujan, M. Margonia,b, A.T. Meneguzzoa,b,M. Passaseoa, N. Pozzobona,b, P. Ronchesea,b, R. Rossina,b, F. Simonettoa,b,E. Torassaa,S. Venturaa, M. Zanettia,b, P. Zottoa,b

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

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

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

L. Alunni Solestizia,b, M. Biasinia,b, G.M. Bileia,C. Cecchia,b,D. Ciangottinia,b, L. Fanòa,b,R. Leonardia,b, E. Manonia,G. Mantovania,b,V. Mariania,b,M. Menichellia, A. Rossia,b,A. Santocchiaa,b, D. Spigaa

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

K. Androsova, P. Azzurria,15,G. Bagliesia,T. Boccalia,L. Borrello, R. Castaldia, M.A. Cioccia,b, R. Dell’Orsoa,G. Fedia, L. Gianninia,c, A. Giassia, M.T. Grippoa,29,F. Ligabuea,c, T. Lomtadzea,

E. Mancaa,c,G. Mandorlia,c, A. Messineoa,b, F. Pallaa,A. Rizzia,b, A. Savoy-Navarroa,31,P. Spagnoloa, R. Tenchinia,G. Tonellia,b, A. Venturia,P.G. Verdinia

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

c_{ScuolaNormaleSuperiorediPisa,Pisa,Italy}

L. Baronea,b, F. Cavallaria,M. Cipriania,b, N. Dacia,D. Del Rea,b,15,E. Di Marcoa,b,M. Diemoza,

S. Gellia,b, E. Longoa,b, F. Margarolia,b,B. Marzocchia,b, P. Meridiania,G. Organtinia,b,R. Paramattia,b, F. Preiatoa,b_{,S. Rahatlou}a,b_{, C. Rovelli}a_{,F. Santanastasio}a,b

a_{INFNSezionediRoma,Rome,Italy} b_{SapienzaUniversitàdiRoma,Rome,Italy}

N. Amapanea,b,R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c,N. Bartosika,R. Bellana,b,C. Biinoa, N. Cartigliaa,F. Cennaa,b, M. Costaa,b,R. Covarellia,b,A. Deganoa,b,N. Demariaa, B. Kiania,b,

C. Mariottia, S. Masellia,E. Migliorea,b, V. Monacoa,b, E. Monteila,b, M. Montenoa,M.M. Obertinoa,b, L. Pachera,b,N. Pastronea, M. Pelliccionia,G.L. Pinna Angionia,b,A. Romeroa,b,M. Ruspaa,c, R. Sacchia,b, K. Shchelinaa,b, V. Solaa,A. Solanoa,b,A. Staianoa,P. Traczyka,b

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

c_{UniversitàdelPiemonteOrientale,Novara,Italy}

S. Belfortea,M. Casarsaa, F. Cossuttia,G. Della Riccaa,b, A. Zanettia

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

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

KyungpookNationalUniversity,Daegu,RepublicofKorea

A. Lee

ChonbukNationalUniversity,Jeonju,RepublicofKorea

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

ChonnamNationalUniversity,InstituteforUniverseandElementaryParticles,Kwangju,RepublicofKorea

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

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

KoreaUniversity,Seoul,RepublicofKorea

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

H.D. Yoo,G.B. Yu

SeoulNationalUniversity,Seoul,RepublicofKorea

H. Kim,J.H. Kim, J.S.H. Lee, I.C. Park

UniversityofSeoul,Seoul,RepublicofKorea

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

SungkyunkwanUniversity,Suwon,RepublicofKorea

V. Dudenas, A. Juodagalvis,J. Vaitkus

VilniusUniversity,Vilnius,Lithuania

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

Z. Zolkapli

NationalCentreforParticlePhysics,UniversitiMalaya,KualaLumpur,Malaysia

R. Reyes-Almanza,G. Ramirez-Sanchez, M.C. Duran-Osuna, H. Castilla-Valdez, E. De La Cruz-Burelo,

I. Heredia-De La Cruz34, R.I. Rabadan-Trejo, R. Lopez-Fernandez,J. Mejia Guisao, A. Sanchez-Hernandez

CentrodeInvestigacionydeEstudiosAvanzadosdelIPN,MexicoCity,Mexico

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

UniversidadIberoamericana,MexicoCity,Mexico

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

BenemeritaUniversidadAutonomadePuebla,Puebla,Mexico

A. Morelos Pineda

UniversidadAutónomadeSanLuisPotosí,SanLuisPotosí,Mexico

D. Krofcheck

UniversityofAuckland,Auckland,NewZealand

P.H. Butler

UniversityofCanterbury,Christchurch,NewZealand

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

NationalCentreforPhysics,Quaid-I-AzamUniversity,Islamabad,Pakistan

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

P. Zalewski

NationalCentreforNuclearResearch,Swierk,Poland

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

M. Olszewski, A. Pyskir,M. Walczak

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

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

LaboratóriodeInstrumentaçãoeFísicaExperimentaldePartículas,Lisboa,Portugal

S. Afanasiev,V. Alexakhin,P. Bunin, M. Gavrilenko, A. Golunov, I. Golutvin, N. Gorbounov, V. Karjavin,

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

V. Smirnov,A. Zarubin

JointInstituteforNuclearResearch,Dubna,Russia

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

V. Sulimov,L. Uvarov, S. Vavilov, A. Vorobyev

PetersburgNuclearPhysicsInstitute,Gatchina(St.Petersburg),Russia

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

A. Pashenkov,D. Tlisov, A. Toropin

InstituteforNuclearResearch,Moscow,Russia

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

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

InstituteforTheoreticalandExperimentalPhysics,Moscow,Russia

T. Aushev,A. Bylinkin37

MoscowInstituteofPhysicsandTechnology,Moscow,Russia

M. Chadeeva40, O. Markin,P. Parygin, D. Philippov,S. Polikarpov, V. Rusinov

NationalResearchNuclearUniversity‘MoscowEngineeringPhysicsInstitute’(MEPhI),Moscow,Russia

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

P.N.LebedevPhysicalInstitute,Moscow,Russia

A. Baskakov,A. Belyaev, E. Boos,V. Bunichev, M. Dubinin41, L. Dudko, V. Klyukhin, N. Korneeva,

I. Lokhtin,I. Miagkov, S. Obraztsov,M. Perfilov, S. Petrushanko,V. Savrin, A. Snigirev

SkobeltsynInstituteofNuclearPhysics,LomonosovMoscowStateUniversity,Moscow,Russia

V. Blinov42, Y. Skovpen42,D. Shtol42

NovosibirskStateUniversity(NSU),Novosibirsk,Russia

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

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

StateResearchCenterofRussianFederation,InstituteforHighEnergyPhysics,Protvino,Russia

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

UniversityofBelgrade,FacultyofPhysicsandVincaInstituteofNuclearSciences,Belgrade,Serbia

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

C. Fernandez Bedoya,J.P. Fernández Ramos, J. Flix, M.C. Fouz,O. Gonzalez Lopez, S. Goy Lopez,

J.M. Hernandez, M.I. Josa,D. Moran, A. Pérez-Calero Yzquierdo, J. Puerta Pelayo, A. Quintario Olmeda,

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

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

UniversidadAutónomadeMadrid,Madrid,Spain

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

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

UniversidaddeOviedo,Oviedo,Spain

I.J. Cabrillo, A. Calderon, B. Chazin Quero,E. Curras, J. Duarte Campderros, M. Fernandez,

J. Garcia-Ferrero,G. Gomez, A. Lopez Virto, J. Marco,C. Martinez Rivero, P. Martinez Ruiz del Arbol,

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, B. Akgun,E. Auffray, P. Baillon,A.H. Ball, D. Barney, J. Bendavid,M. Bianco, P. Bloch,

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

A. Dabrowski,V. Daponte, A. David, M. De Gruttola, A. De Roeck, N. Deelen,M. Dobson, T. du Pree,

M. Dünser,N. Dupont, A. Elliott-Peisert,P. Everaerts, F. Fallavollita,G. Franzoni, J. Fulcher, W. Funk,

D. Gigi,A. Gilbert, K. Gill,F. Glege, D. Gulhan, P. Harris,J. Hegeman, V. Innocente, A. Jafari, P. Janot,

O. Karacheban18,J. Kieseler, V. Knünz, A. Kornmayer,M.J. Kortelainen, M. Krammer1,C. Lange, P. Lecoq,

C. Lourenço,M.T. Lucchini, L. Malgeri,M. Mannelli, A. Martelli,F. Meijers, J.A. Merlin, S. Mersi, E. Meschi,

P. Milenovic44, F. Moortgat, M. Mulders, H. Neugebauer,J. Ngadiuba, S. Orfanelli, L. Orsini, L. Pape,

E. Perez,M. Peruzzi, A. Petrilli, G. Petrucciani,A. Pfeiffer, M. Pierini,D. Rabady, A. Racz,T. Reis,

G. Rolandi45, M. Rovere, H. Sakulin, C. Schäfer, C. Schwick,M. Seidel, M. Selvaggi,A. Sharma,P. Silva,

P. Sphicas46, A. Stakia,J. Steggemann, M. Stoye,M. Tosi, D. Treille, A. Triossi,A. Tsirou, V. Veckalns47,

M. Verweij, W.D. Zeuner

CERN,EuropeanOrganizationforNuclearResearch,Geneva,Switzerland

W. Bertl†, L. Caminada48, K. Deiters,W. Erdmann, R. Horisberger, Q. Ingram, H.C. Kaestli, D. Kotlinski,

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

PaulScherrerInstitut,Villigen,Switzerland

M. Backhaus, L. Bäni, P. Berger, L. Bianchini, B. Casal, G. Dissertori,M. Dittmar, M. Donegà, C. Dorfer,

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

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

F. Pauss,G. Perrin, L. Perrozzi,M. Quittnat, M. Reichmann, D.A. Sanz Becerra,M. Schönenberger,

L. Shchutska,V.R. Tavolaro, K. Theofilatos, M.L. Vesterbacka Olsson, R. Wallny, D.H. Zhu

ETHZurich–InstituteforParticlePhysicsandAstrophysics(IPA),Zurich,Switzerland

T.K. Aarrestad, C. Amsler49, M.F. Canelli,A. De Cosa, R. Del Burgo, S. Donato, C. Galloni, T. Hreus,

B. Kilminster, D. Pinna,G. Rauco, P. Robmann, D. Salerno, K. Schweiger, C. Seitz, Y. Takahashi,

A. Zucchetta

UniversitätZürich,Zurich,Switzerland

V. Candelise,Y.H. Chang, K.y. Cheng,T.H. Doan, Sh. Jain,R. Khurana, C.M. Kuo, W. Lin, A. Pozdnyakov,

S.S. Yu

NationalCentralUniversity,Chung-Li,Taiwan

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

R.-S. Lu, E. Paganis, A. Psallidas,A. Steen, J.f. Tsai

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

ChulalongkornUniversity,FacultyofScience,DepartmentofPhysics,Bangkok,Thailand

M.N. Bakirci50,A. Bat, F. Boran,S. Cerci51, S. Damarseckin, Z.S. Demiroglu, C. Dozen, E. Eskut, S. Girgis,

G. Gokbulut,Y. Guler, I. Hos52, E.E. Kangal53,O. Kara, U. Kiminsu, M. Oglakci,G. Onengut54,

K. Ozdemir55,S. Ozturk50,U.G. Tok, H. Topakli50,S. Turkcapar, I.S. Zorbakir, C. Zorbilmez

ÇukurovaUniversity,PhysicsDepartment,ScienceandArtFaculty,Adana,Turkey

G. Karapinar56, K. Ocalan57,M. Yalvac, M. Zeyrek

MiddleEastTechnicalUniversity,PhysicsDepartment,Ankara,Turkey

E. Gülmez,M. Kaya58,O. Kaya59, S. Tekten, E.A. Yetkin60

BogaziciUniversity,Istanbul,Turkey

M.N. Agaras,S. Atay, A. Cakir, K. Cankocak, I. Köseoglu

IstanbulTechnicalUniversity,Istanbul,Turkey

B. Grynyov

InstituteforScintillationMaterialsofNationalAcademyofScienceofUkraine,Kharkov,Ukraine

L. Levchuk

NationalScientificCenter,KharkovInstituteofPhysicsandTechnology,Kharkov,Ukraine

F. Ball, L. Beck, J.J. Brooke,D. Burns, E. Clement, D. Cussans,O. Davignon, H. Flacher,J. Goldstein,

G.P. Heath, H.F. Heath,L. Kreczko, D.M. Newbold61, S. Paramesvaran,T. Sakuma, S. Seif El Nasr-storey,

D. Smith,V.J. Smith

UniversityofBristol,Bristol,UnitedKingdom

K.W. Bell,A. Belyaev62,C. Brew, R.M. Brown, L. Calligaris,D. Cieri, D.J.A. Cockerill, J.A. Coughlan,

K. Harder,S. Harper, J. Linacre, E. Olaiya,D. Petyt, C.H. Shepherd-Themistocleous, A. Thea, I.R. Tomalin,

T. Williams

RutherfordAppletonLaboratory,Didcot,UnitedKingdom

G. Auzinger, R. Bainbridge,J. Borg,S. Breeze, O. Buchmuller, A. Bundock,S. Casasso, M. Citron,D. Colling,

L. Corpe,P. Dauncey, G. Davies, A. De Wit, M. Della Negra, R. Di Maria, A. Elwood, Y. Haddad, G. Hall,

G. Iles, T. James, R. Lane, C. Laner, L. Lyons, A.-M. Magnan,S. Malik, L. Mastrolorenzo, T. Matsushita,

J. Nash, A. Nikitenko7,V. Palladino, M. Pesaresi, D.M. Raymond, A. Richards,A. Rose, E. Scott,C. Seez,

A. Shtipliyski,S. Summers,A. Tapper, K. Uchida, M. Vazquez Acosta63,T. Virdee15,N. Wardle,

D. Winterbottom,J. Wright, S.C. Zenz

ImperialCollege,London,UnitedKingdom

J.E. Cole, P.R. Hobson,A. Khan, P. Kyberd,I.D. Reid, L. Teodorescu, S. Zahid

BrunelUniversity,Uxbridge,UnitedKingdom

A. Borzou,K. Call,J. Dittmann, K. Hatakeyama, H. Liu, N. Pastika, C. Smith

BaylorUniversity,Waco,USA

R. Bartek,A. Dominguez

A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio,C. West

TheUniversityofAlabama,Tuscaloosa,USA

D. Arcaro, A. Avetisyan, T. Bose, D. Gastler, D. Rankin, C. Richardson,J. Rohlf, L. Sulak, D. Zou

BostonUniversity,Boston,USA

G. Benelli, D. Cutts, A. Garabedian, M. Hadley,J. Hakala, U. Heintz, J.M. Hogan, K.H.M. Kwok,E. Laird,

G. Landsberg, J. Lee,Z. Mao, M. Narain, J. Pazzini, S. Piperov,S. Sagir, R. Syarif, D. Yu

BrownUniversity,Providence,USA

R. Band,C. Brainerd, R. Breedon, D. Burns,M. Calderon De La Barca Sanchez, M. Chertok, J. Conway,

R. Conway, P.T. Cox, R. Erbacher,C. Flores, G. Funk, W. Ko, R. Lander, C. Mclean, M. Mulhearn, D. Pellett,

J. Pilot, S. Shalhout, M. Shi,J. Smith, D. Stolp, K. Tos, M. Tripathi,Z. Wang

UniversityofCalifornia,Davis,Davis,USA

M. Bachtis,C. Bravo, R. Cousins,A. Dasgupta, A. Florent,J. Hauser, M. Ignatenko, N. Mccoll, S. Regnard,

D. Saltzberg, C. Schnaible, V. Valuev

UniversityofCalifornia,LosAngeles,USA

E. Bouvier, K. Burt, R. Clare, J. Ellison,J.W. Gary, S.M.A. Ghiasi Shirazi,G. Hanson, J. Heilman,

G. Karapostoli,E. Kennedy, F. Lacroix, O.R. Long, M. Olmedo Negrete, M.I. Paneva,W. Si, L. Wang, H. Wei,

S. Wimpenny,B.R. Yates

UniversityofCalifornia,Riverside,Riverside,USA

J.G. Branson, S. Cittolin, M. Derdzinski, R. Gerosa, D. Gilbert, B. Hashemi, A. Holzner, D. Klein,G. Kole,

V. Krutelyov, J. Letts, M. Masciovecchio, D. Olivito,S. Padhi, M. Pieri, M. Sani, V. Sharma, M. Tadel,

A. Vartak, S. Wasserbaech64,J. Wood, F. Würthwein,A. Yagil, G. Zevi Della Porta

UniversityofCalifornia,SanDiego,LaJolla,USA

N. Amin, R. Bhandari, J. Bradmiller-Feld, C. Campagnari, A. Dishaw,V. Dutta, M. Franco Sevilla,

L. Gouskos,R. Heller, J. Incandela, A. Ovcharova, H. Qu,J. Richman, D. Stuart, I. Suarez,J. Yoo

UniversityofCalifornia,SantaBarbara–DepartmentofPhysics,SantaBarbara,USA

D. Anderson,A. Bornheim, J.M. Lawhorn,H.B. Newman, T. Nguyen, C. Pena,M. Spiropulu, J.R. Vlimant,

S. Xie, Z. Zhang, R.Y. Zhu

CaliforniaInstituteofTechnology,Pasadena,USA

M.B. Andrews,T. Ferguson, T. Mudholkar, M. Paulini, J. Russ, M. Sun, H. Vogel, I. Vorobiev,M. Weinberg

CarnegieMellonUniversity,Pittsburgh,USA

J.P. Cumalat, W.T. Ford,F. Jensen, A. Johnson, M. Krohn,S. Leontsinis, T. Mulholland, K. Stenson,

S.R. Wagner

UniversityofColoradoBoulder,Boulder,USA

J. Alexander, J. Chaves,J. Chu, S. Dittmer, K. Mcdermott, N. Mirman, J.R. Patterson,D. Quach,

A. Rinkevicius, A. Ryd,L. Skinnari, L. Soffi, S.M. Tan,Z. Tao, J. Thom, J. Tucker, P. Wittich, M. Zientek

CornellUniversity,Ithaca,USA

S. Abdullin,M. Albrow, M. Alyari, G. Apollinari,A. Apresyan,A. Apyan, S. Banerjee, L.A.T. Bauerdick,

A. Beretvas,J. Berryhill, P.C. Bhat, G. Bolla†,K. Burkett, J.N. Butler,A. Canepa, G.B. Cerati, H.W.K. Cheung,