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https://www.sciencedirect.com/science/article/pii/S0370269318300571
DOI: 10.1016/j.physletb.2018.01.049
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©2018 by Elsevier. All rights reserved.
DIRETORIA DE TRATAMENTO DA INFORMAÇÃO Cidade Universitária Zeferino Vaz Barão Geraldo
CEP 13083-970 – Campinas SP Fone: (19) 3521-6493 http://www.repositorio.unicamp.br
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
.TheCMS Collaboration CERN, Switzerland a r t i c l e i n f o a b s t ra c t Article history: Received29November2017Receivedinrevisedform16January2018 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-mail address: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. TheCMSdetectorandsimulatedsamples
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. Eventreconstruction
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. Eventselection
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-tionof mt∗.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)×104 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 pmissT 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. Massreconstruction
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. Backgroundmodeling
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
Fig. 1. Kinematicdistributionsofselectedeventswithasingleleptonandsixormorejetsofwhichexactlytwoareb tagged.Dataevents(points),simulatedbackground processes(stackedhistograms),andasimulated800 GeV signalprocess(dashedline)areshown.Eventsselectedintheμ+jetfinalstateareshownontheleftwhilethose inthee+jetfinalstateareshownontheright.Fromuppertolower,thekinematicvariablesdisplayedarethelepton pT,thejet pTandthe mt+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. Systematicuncertainties
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 componentaredenotedby Kalland Kbkg,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 pmissT .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. Statisticalanalysisandextractionoflimits
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. Theexpectedandobserved95%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). References
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TheCMSCollaboration
A.M. Sirunyan,A. Tumasyan
Yerevan Physics Institute, 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
Institut für Hochenergiephysik, Wien, Austria
V. Chekhovsky, V. Mossolov,J. Suarez Gonzalez
Institute for Nuclear Problems, 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
Universiteit Antwerpen, 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
Vrije Universiteit Brussel, 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
Université Libre de Bruxelles, 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
Université Catholique de Louvain, 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
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, 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
Universidade do Estado do Rio de Janeiro, Rio de Janeiro, 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
aUniversidade Estadual Paulista, São Paulo, Brazil bUniversidade Federal do ABC, São Paulo, Brazil
A. Aleksandrov, R. Hadjiiska, P. Iaydjiev,M. Misheva, M. Rodozov, M. Shopova,G. Sultanov
Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Bulgaria
A. Dimitrov, L. Litov,B. Pavlov, P. Petkov
University of Sofia, Sofia, Bulgaria
W. Fang6, X. Gao6,L. Yuan
Beihang University, 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
Institute of High Energy Physics, Beijing, China
Y. Ban, G. Chen, J. Li,Q. Li, S. Liu, Y. Mao,S.J. Qian, D. Wang, Z. Xu
State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China
Y. Wang
Tsinghua University, Beijing, China
C. Avila,A. Cabrera, L.F. Chaparro Sierra, C. Florez, C.F. González Hernández,J.D. Ruiz Alvarez,
M.A. Segura Delgado
Universidad de Los Andes, Bogota, Colombia
B. Courbon, N. Godinovic, D. Lelas,I. Puljak, P.M. Ribeiro Cipriano, T. Sculac
University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia
Z. Antunovic, M. Kovac
University of Split, Faculty of Science, 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
University of Cyprus, Nicosia, Cyprus
M. Finger8,M. Finger Jr.8
Charles University, Prague, Czech Republic
E. Carrera Jarrin
Universidad San Francisco de Quito, Quito, Ecuador
E. El-khateeb9,S. Elgammal10,A. Mohamed11
Academy of Scientific Research and Technology of the Arab Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt
R.K. Dewanjee,M. Kadastik, L. Perrini, M. Raidal, A. Tiko,C. Veelken
National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
P. Eerola,H. Kirschenmann, J. Pekkanen,M. Voutilainen
Department of Physics, University of Helsinki, 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
Helsinki Institute of Physics, Helsinki, Finland
T. Tuuva
Lappeenranta University of Technology, 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, Université Paris-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
Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Université Paris-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
Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
S. Gadrat
Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique des Particules, 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
Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucléaire de Lyon, Villeurbanne, France
T. Toriashvili14
Z. Tsamalaidze8
Tbilisi State University, Tbilisi, Georgia
C. Autermann, L. Feld, M.K. Kiesel, K. Klein, M. Lipinski, M. Preuten,C. Schomakers, J. Schulz,
M. Teroerde,V. Zhukov13
RWTH Aachen University, I. Physikalisches Institut, 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
RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany
G. Flügge, B. Kargoll, T. Kress, A. Künsken, T. Müller,A. Nehrkorn, A. Nowack, C. Pistone,O. Pooth,
A. Stahl15
RWTH Aachen University, III. Physikalisches Institut B, 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
Deutsches Elektronen-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
University of Hamburg, 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
Institut für Experimentelle Kernphysik, Karlsruhe, Germany
G. Anagnostou, G. Daskalakis,T. Geralis,A. Kyriakis, D. Loukas, I. Topsis-Giotis
Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece
G. Karathanasis,S. Kesisoglou, A. Panagiotou, N. Saoulidou
National and Kapodistrian University of Athens, 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
University of Ioánnina, Ioánnina, Greece
M. Csanad,N. Filipovic, G. Pasztor,O. Surányi, G.I. Veres19
MTA-ELTE Lendület CMS Particle and Nuclear Physics Group, Eötvös Loránd University, Budapest, Hungary
G. Bencze,C. Hajdu, D. Horvath20, Á. Hunyadi, F. Sikler,V. Veszpremi
Wigner Research Centre for Physics, Budapest, Hungary
N. Beni,S. Czellar, J. Karancsi21,A. Makovec,J. Molnar, Z. Szillasi
Institute of Nuclear Research ATOMKI, Debrecen, Hungary
M. Bartók19,P. Raics, Z.L. Trocsanyi, B. Ujvari
Institute of Physics, University of Debrecen, Debrecen, Hungary
S. Choudhury,J.R. Komaragiri
Indian Institute of Science (IISc), Bangalore, India
S. Bahinipati22,S. Bhowmik, P. Mal, K. Mandal, A. Nayak23, D.K. Sahoo22, N. Sahoo,S.K. Swain
National Institute of Science Education and Research, 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
Panjab University, 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
University of Delhi, 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
Saha Institute of Nuclear Physics, HBNI, Kolkata, India
P.K. Behera
Indian Institute of Technology Madras, Madras, India
R. Chudasama,D. Dutta, V. Jha, V. Kumar, A.K. Mohanty15, P.K. Netrakanti,L.M. Pant, P. Shukla,A. Topkar
Bhabha Atomic Research Centre, Mumbai, India
T. Aziz,S. Dugad, B. Mahakud, S. Mitra, G.B. Mohanty, N. Sur, B. Sutar
Tata Institute of Fundamental Research-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
Tata Institute of Fundamental Research-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
Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
M. Felcini,M. Grunewald
University College Dublin, 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
aINFN Sezione di Bari, Bari, Italy bUniversità di Bari, Bari, Italy cPolitecnico di Bari, 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
aINFN Sezione di Bologna, Bologna, Italy bUniversità di Bologna, Bologna, Italy
S. Albergoa,b,S. Costaa,b,A. Di Mattiaa,F. Giordanoa,b,R. Potenzaa,b,A. Tricomia,b,C. Tuvea,b
aINFN Sezione di Catania, Catania, Italy bUniversità di Catania, 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
aINFN Sezione di Firenze, Firenze, Italy bUniversità di Firenze, Firenze, Italy
L. Benussi, S. Bianco, F. Fabbri,D. Piccolo, F. Primavera15
INFN Laboratori Nazionali di Frascati, Frascati, Italy
V. Calvellia,b, F. Ferroa, F. Raveraa,b,E. Robuttia,S. Tosia,b
aINFN Sezione di Genova, Genova, Italy bUniversità di Genova, 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
aINFN Sezione di Milano-Bicocca, Milano, Italy bUniversità di Milano-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
aINFN Sezione di Napoli, Napoli, Italy bUniversità di Napoli ‘Federico II’, Napoli, Italy cUniversità della Basilicata, Potenza, Italy dUniversità G. 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
aINFN Sezione di Padova, Padova, Italy bUniversità di Padova, Padova, Italy cUniversità di Trento, 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
aINFN Sezione di Pavia, Pavia, Italy bUniversità di Pavia, 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
aINFN Sezione di Perugia, Perugia, Italy bUniversità di Perugia, 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
aINFN Sezione di Pisa, Pisa, Italy bUniversità di Pisa, Pisa, Italy
cScuola Normale Superiore di Pisa, 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. Rahatloua,b, C. Rovellia,F. Santanastasioa,b
aINFN Sezione di Roma, Rome, Italy bSapienza Università di Roma, 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
aINFN Sezione di Torino, Torino, Italy bUniversità di Torino, Torino, Italy
cUniversità del Piemonte Orientale, Novara, Italy
S. Belfortea,M. Casarsaa, F. Cossuttia,G. Della Riccaa,b, A. Zanettia
aINFN Sezione di Trieste, Trieste, Italy bUniversità di Trieste, 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
Kyungpook National University, Daegu, Republic of Korea
A. Lee
Chonbuk National University, Jeonju, Republic of Korea
H. Kim,D.H. Moon,G. Oh
Chonnam National University, Institute for Universe and Elementary Particles, Kwangju, Republic of Korea
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
Korea University, Seoul, Republic of Korea
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
Seoul National University, Seoul, Republic of Korea
H. Kim,J.H. Kim, J.S.H. Lee, I.C. Park
University of Seoul, Seoul, Republic of Korea
Y. Choi,C. Hwang, J. Lee, I. Yu
Sungkyunkwan University, Suwon, Republic of Korea
V. Dudenas, A. Juodagalvis,J. Vaitkus
Vilnius University, 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
National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, 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
Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico
S. Carrillo Moreno, C. Oropeza Barrera, F. Vazquez Valencia
Universidad Iberoamericana, Mexico City, Mexico
J. Eysermans, I. Pedraza, H.A. Salazar Ibarguen, C. Uribe Estrada
Benemerita Universidad Autonoma de Puebla, Puebla, Mexico
A. Morelos Pineda
Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
D. Krofcheck
University of Auckland, Auckland, New Zealand
P.H. Butler
University of Canterbury, Christchurch, New Zealand
A. Ahmad, M. Ahmad, Q. Hassan,H.R. Hoorani, A. Saddique, M.A. Shah, M. Shoaib, M. Waqas
National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan
H. Bialkowska, M. Bluj,B. Boimska, T. Frueboes,M. Górski, M. Kazana, K. Nawrocki, M. Szleper,
P. Zalewski
National Centre for Nuclear Research, 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
Laboratório de Instrumentação e Física Experimental de Partículas, 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
Joint Institute for Nuclear Research, 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
Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia
Yu. Andreev,A. Dermenev,S. Gninenko, N. Golubev, A. Karneyeu, M. Kirsanov,N. Krasnikov,
A. Pashenkov,D. Tlisov, A. Toropin
Institute for Nuclear Research, Moscow, Russia
V. Epshteyn,V. Gavrilov, N. Lychkovskaya,V. Popov, I. Pozdnyakov,G. Safronov, A. Spiridonov,
A. Stepennov, M. Toms,E. Vlasov, A. Zhokin
Institute for Theoretical and Experimental Physics, Moscow, Russia
T. Aushev,A. Bylinkin37
Moscow Institute of Physics and Technology, Moscow, Russia
M. Chadeeva40, O. Markin,P. Parygin, D. Philippov,S. Polikarpov, V. Rusinov
National Research Nuclear University ‘Moscow Engineering Physics Institute’ (MEPhI), Moscow, Russia
V. Andreev,M. Azarkin37,I. Dremin37, M. Kirakosyan37,A. Terkulov
P.N. Lebedev Physical Institute, 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
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
V. Blinov42, Y. Skovpen42,D. Shtol42
Novosibirsk State University (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
State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, Russia
P. Adzic43,P. Cirkovic, D. Devetak,M. Dordevic, J. Milosevic,V. Rekovic
University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, 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
Universidad Autónoma de Madrid, 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
Universidad de Oviedo, 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
Instituto de Física de Cantabria (IFCA), CSIC-Universidad de Cantabria, 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, European Organization for Nuclear Research, 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
Paul Scherrer Institut, 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
ETH Zurich – Institute for Particle Physics and Astrophysics (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
Universität Zürich, 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
National Central University, 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
Chulalongkorn University, Faculty of Science, Department of Physics, 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
Çukurova University, Physics Department, Science and Art Faculty, Adana, Turkey
G. Karapinar56, K. Ocalan57,M. Yalvac, M. Zeyrek
Middle East Technical University, Physics Department, Ankara, Turkey
E. Gülmez,M. Kaya58,O. Kaya59, S. Tekten, E.A. Yetkin60
Bogazici University, Istanbul, Turkey
M.N. Agaras,S. Atay, A. Cakir, K. Cankocak, I. Köseoglu
Istanbul Technical University, Istanbul, Turkey
B. Grynyov
Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine
L. Levchuk
National Scientific Center, Kharkov Institute of Physics and Technology, 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
University of Bristol, Bristol, United Kingdom
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
Rutherford Appleton Laboratory, Didcot, United Kingdom
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
Imperial College, London, United Kingdom
J.E. Cole, P.R. Hobson,A. Khan, P. Kyberd,I.D. Reid, L. Teodorescu, S. Zahid
Brunel University, Uxbridge, United Kingdom
A. Borzou,K. Call,J. Dittmann, K. Hatakeyama, H. Liu, N. Pastika, C. Smith
Baylor University, Waco, USA
R. Bartek,A. Dominguez
A. Buccilli, S.I. Cooper, C. Henderson, P. Rumerio,C. West
The University of Alabama, Tuscaloosa, USA
D. Arcaro, A. Avetisyan, T. Bose, D. Gastler, D. Rankin, C. Richardson,J. Rohlf, L. Sulak, D. Zou
Boston University, 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
Brown University, 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
University of California, 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
University of California, Los Angeles, 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
University of California, 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
University of California, San Diego, La Jolla, 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
University of California, Santa Barbara – Department of Physics, Santa Barbara, 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
California Institute of Technology, Pasadena, USA
M.B. Andrews,T. Ferguson, T. Mudholkar, M. Paulini, J. Russ, M. Sun, H. Vogel, I. Vorobiev,M. Weinberg
Carnegie Mellon University, Pittsburgh, USA
J.P. Cumalat, W.T. Ford,F. Jensen, A. Johnson, M. Krohn,S. Leontsinis, T. Mulholland, K. Stenson,
S.R. Wagner
University of Colorado Boulder, 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
Cornell University, 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,
