Search for a heavy composite Majorana neutrino in the final state with two leptons and two quarks at $\sqrt{s}=13$ TeV

Contents lists available atScienceDirect

Physics

Letters

B

www.elsevier.com/locate/physletb

Search

for

a

heavy

composite

Majorana

neutrino

in

the

final

state

with

two

leptons

and

two

quarks

at

√

s

=

13

TeV

.TheCMS Collaboration

CERN,Switzerland

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

Articlehistory:

Received1July2017

Receivedinrevisedform14October2017 Accepted1November2017

Availableonline6November2017 Editor:M.Doser

Keywords:

CMS Exotica

A search for physics beyond the standard model in the final state with two same-flavour leptons (electronsormuons)andtwoquarksproducedinproton–protoncollisionsat√s=13TeV ispresented. The data were recorded by the CMS experiment atthe CERN LHC and correspond to an integrated luminosity of2.3fb−1_{.Theobserveddata areingoodagreementwiththestandardmodelbackground}

prediction. The resultsof the measurementare interpreted in the framework ofarecently proposed model in whichaheavy Majorana neutrino, N,stems from acomposite-fermion scenario. Exclusion

limits areset forthe firsttimeonthe massoftheheavy compositeMajorananeutrino,mN,andthe compositenessscale.ForthecasemN= ,theexistenceofNe(Nμ)isexcludedformassesupto4.60 (4.70) TeVat95%confidencelevel.

©2017TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/).FundedbySCOAP3_.

1. Introduction

Experimentalevidencehaspromoted thestandardmodel(SM) totheroleofthereferencetheoryforhigh-energyparticlephysics. Despiteitssuccesses,thereareseveralfundamentalaspectsof ob-servedparticlephysicsthatlackacompleteexplanationwithinthe SM. One of these is the mass hierarchy of fermions, for which a possiblesolution has beenoffered by composite-fermion mod-els[1–3].

Inthecomposite-fermionscenario, quarksandleptons are as-sumedtohaveaninternalsubstructurethatshouldmanifestitself atsomesufficientlyhighenergyscale,thecompositenessscale. Ordinary fermions are considered as bound states of some not yet observed fundamental constituents generically referred to as preons. Two model-independent properties [4–7] are experimen-tally relevant: the existence of a contact interaction, in addition to the gauge interaction, which represents an effective approach for describing the effects of the unknown internal dynamics of compositeness,and theexistence ofexcited statesof quarksand leptonswithmasseslowerthanorequalto.Aparticularcaseof suchexcitedstatescouldbeaheavycompositeMajorananeutrino (HCMN),N(=e, μ, τ)[8–11].

In this Letter we present, for the first time, the results of a search for heavy composite Majorana neutrinos predicted in the

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

framework of a newmodel described in Ref. [12]. In that refer-ence, the production and decay of N are analyzed, considering

bothgauge andcontactinteractions.Thetotal interactionisgiven by the coherentsumofthe contactandthe gauge contributions, asshowninFig. 1. Thecontribution ofthecontactinteractionto the productioncrosssection istwo to threeorders ofmagnitude highercomparedtothatofthegaugeinteraction[12].

Thecontactinteractionisdescribedbyaneffectivefour-fermion Lagrangianofthetype

LC= g2_∗ 2 1 2j μ_j μ, (1) with jμ=ηaLf¯LγμfL+ηbLf¯L∗γμfL∗+ηLcf¯L∗γμfL+h.c.+ (L→R), (2) where fL and fL∗ are the SM and excited left-handed fermion fields, g2

∗=4π,andthe η factors,which define the chiral struc-ture, areset equaltoone. Thegauge interactionbetweentheSM fermionsandtheexcitedfermionsisdescribedbyamagnetic-type coupling LG= 1 2L ∗ Rσμν  g f − →_τ 2 · − → Wμν+gfY Bμν  LL+h.c. (3) where L∗_R and LL are the right-handed excited doublet and left-handed SM doublet, g and g are the SU(2)L and U(1)Y gauge https://doi.org/10.1016/j.physletb.2017.11.001

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

Fig. 1. Leading orderdiagrams representingheavy composite Majorana neutrino production.Thetotalinteractionisthecoherentsumofthegaugeandcontact in-teractions.Charge-conjugatereactionsareimplied.SeeRef.[12].

Fig. 2. Productioncrosssectioninppcollisionsat√s=13TeV oftheheavy compos-iteMajorananeutrinoviagaugeandcontactinteractionsasafunctionofMajorana massat=9TeV (top)anddecaywidthoftheheavycompositeMajorananeutrino for=9TeV asafunctionofitsmass(bottom).ThefiguresillustrateLOresultsof calculationsbasedonRef.[12].

couplings,−→Wμν andBμν arethefieldstrengthsfortheSU(2)Land U(1)_Ygaugefields,respectively,−→τ arethePaulimatrices, Y isthe weakhypercharge,and f and f aredimensionlesscouplings, as-sumedtobe1[7].

From the Lagrangians in Eqs. (1) and (3) we can infer that the higher the value of , the lower the production cross sec-tion of the heavy composite Majorana neutrino. Since N is its

ownantiparticle,itcanbeproducedeitherasaneutrinooran an-tineutrino.In ppcollisionsit canbeproduced inassociationwith aleptonthrough quark–antiquarkannihilation(qq→ +N). This

processcanoccurviabothgaugeandcontactinteractions.The lat-terisdominantforawiderangeofvalues,includingtheonesto whichwearesensitiveinthissearch.Fig. 2(top)showsthe lead-ing order (LO) production cross section, as a function of the N

mass,forthe case=9 TeV, whichis oneof thevalues consid-eredinthisLetterwhosecalculationisbasedonRef.[12].

The heavy composite Majorana neutrino can decay through bothgaugeandcontactinteractions.Inthiscase,eitherthegauge orthecontactinteractionisdominant,dependingonandonthe massofN,asillustratedinFig. 2(bottom).

BeingaMajoranaparticle,N candecayeitherasaneutrinoor

anantineutrinowithpossibledecaymodes:

N→ qq, N→ +−ν(ν), N→ν(ν)qq,

where the parenthesesindicate that the decayproduct can be a neutrinooranantineutrino.Thepossiblefinalstatesare:

qq, ν(ν), ν(ν)qq.

In thisLetter,the final state qq is considered,asit hasthe highestsensitivity.We focusonthecasesinwhich iseitheran electronoramuon,givingrisetothechannelseeqqand μμqq.

Forour analysisweuse adata sample ofproton–proton colli-sions at √s=13TeV recordedin 2015withthe CMSdetectorat the CERN LHC,which corresponds to an integratedluminosity of 2.3fb−1 [13].

Previous searchesforcompositeness modelshavebeencarried outatpp,pp,e+e−,andepcolliders.Themostrecentresults,from the ATLAS and CMS Collaborations, are given in [14,15] and ex-clude theexistence ofexcited electrons (muons) up tomassesof 2.45(2.47) TeVat95%confidencelevel(CL),forthecasem∗= .

The search performed in the context of Ref. [12], which is dis-cussed below, can reach a sensitivity for the existence of heavy compositeMajorananeutrinosup tomassesof4.55(4.77) TeVfor Ne(Nμ),forthecasem∗= .

Direct searches for heavy neutrinos have been performed by theATLAS[16,17]andCMS[18–21]Collaborations.Theseprevious searcheshavebeenperformedintheqq(=e, μ, τ)channels, consideringtwoleptonsandtwospatiallyseparatedjets.However, inourcase, thisselectionhaslimitedacceptanceforgauge boson mediated decays,forwhich thetwo jetsare expectedtooverlap, as they originate fromhighly Lorentz-boostedhadronic W boson decay products. We overcome thisconstraint by selecting events withatleastone jetwithangularradiuslarge enoughto contain a merged pairof partons.Such a requirementis alsohighly effi-cient forheavy compositeMajorananeutrinodecaysmediated by thecontactinteraction,whereweselectonlyoneofthetwodecay jets,asdescribedlaterinthispaper.Thisfinalselection,considered for thefirst time in a search forheavy neutrinos,could improve thesensitivityofsearchesforheavyneutrinosintheframeworkof othermodels,suchastheoneconsideredinRefs.[19,20].

2. TheCMSdetector

The centralfeatureoftheCMSapparatusisa superconducting solenoid,of6 minternaldiameter,providingafieldof3.8 T.Within thefield volumearetheinnertracker,thecrystalelectromagnetic calorimeter(ECAL),andthebrassandscintillatorhadron calorime-ter(HCAL).Theinnertrackeriscomposedofapixel detectorand a silicon strip tracker, and measures charged-particle trajectories inthe pseudorapidityrange|η|<2.5.ThefinelysegmentedECAL consistsofnearly 76000 lead-tungstatecrystalsthatprovide cov-erageupto|η|=3.0.TheHCALconsistsofasamplingcalorimeter, whichutilizesalternating layersofbrassasan absorberand plas-ticscintillatorasanactivematerial,coveringtherange|η|<3,and isextendedto|η|<5 byaforwardhadroncalorimeter.Themuon systemcoverstheregion|η|<2.4 andconsistsofuptofourplanes ofgasionizationmuondetectorsinstalledoutsidethesolenoidand sandwichedbetweenthelayersofthesteelflux-returnyoke.A de-taileddescriptionoftheCMSdetectorcanbefoundelsewhere[22].

3. Datasamplesandsimulation

Monte Carlo (MC) event generators are used to simulate the signal andtheSM backgroundprocesses.TheMCsamplesforthe signal are generatedatLOwith CalcHEP (v3.6) [23] forfour val-uesoftheparameter : 1,5,9,and13 TeV andsixvaluesofthe heavy composite Majorana neutrino mass: 0.5, 1.5, 2.5, 3.5, 4.5,

and6.5 TeV,butonlyforthecasesinwhichmN islowerthan . Thesignalsamplesproducedwith=9TeV areusedasreference samplesin the analysis, while the samplesgenerated with other valuesofareusedtostudyhowthesignalefficiencychanges,as discussedinSection4.

Thesimulationsfortheprocessestt,tW,andtW (thelattertwo referred as tW in the rest of the paper) are performed at next-to-the-leading order (NLO) with powheg (v2)[24–26],while the Drell–Yan(DY)andthe W+jetssamplesare generatedwith Mad-Graph5_amc@nlo (v5.2)[27].TheWW,WZ,andZZprocessesare producedwith pythia (v8.2)[28]andarenormalizedtoNLO.

The NNPDF 3.0 [29] parton distribution functions (PDF) are used,andallsimulatedsamplesusethe pythia programwiththe CUETP8M1tune[30]todescribepartonshoweringand hadroniza-tion.Additionalcollisionsinthesameoradjacentbunchcrossings (pileup)aretakeninto accountby superimposingsimulated min-imum bias interactions onto the hard scatteringprocess, with a number distribution matching that observed in data. Simulated events are propagated through the full Geant4 based simula-tion[31]oftheCMSdetector.

4. Eventselection

Single-leptontriggersthatrequireeitheranelectronwith trans-verse momentum pT>105GeV or a muon with pT >50GeV within |η|<2.4,are thus usedto selectevents inthe eeqq and μμqq channels, respectively. As the signal is characterized by high-momentumleptons inthe final state, thedifference in trig-gerthresholdsdoesnotaffecttherelativesignalsensitivity.

Electronsare reconstructedas superclustersin theECAL asso-ciatedwith tracksinthe trackingdetector[32].Requirements on energydepositsinthecalorimeterandnumberoftrack measure-mentsare imposed todistinguish promptelectrons fromcharged pionsandfromelectronsproducedbyphotonconversions.Muons arereconstructedusingtheinnertrackerandmuondetectors[33]. Qualityrequirements,basedontheminimumnumberof measure-mentsinthesilicontracker,pixeldetector,andmuondetectorsare appliedinordertosuppressbackgrounds fromdecaysinflightof hadronsandfromhadron shower remnants that reachthe muon system. We require exactly two electrons or exactly two muons andthe twoleptons mustcomefromthesamevertex.The pT of theleading(subleading)electronisrequiredtobehigherthan110 (35) GeV; the corresponding threshold formuons is 53 (30) GeV. Allleptoncandidateshavetobereconstructedwithin|η|<2.4 and topass isolation requirements,asspecifiedin [32,33]in orderto reducebackgroundfrommisidentifiedjets.

Jetsarereconstructedusingtheanti-kTclusteringalgorithm[34,

35]appliedtotheobjectsreconstructedwiththeparticle-flow(PF) algorithm[36].ThelattercombinesinformationfromallCMS sub-detectorsandreconstructsindividual particles inthe event (elec-trons,muons, photons, neutralandchargedhadrons).Jetsare re-constructedwithadistanceparameterofR=0.8,andarereferred toas“large-radiusjets”(andlabelledbythesymbol“J”)intherest ofthetext. This distanceparameteris suitable forreconstructing jetsthat originate fromboth gauge and contactinteractions. The large-radius jets are required to have a pT>190GeV, |η|<2.4, andtobeseparatedfromleptonsbyR=(η)2_{+ (φ)}2_>0.8, whereφistheazimuthalangle.

Using MC signal samples we find that requiring one or more large-radiusjetsguarantees highsignal efficiencyforevents with twoleptons(greaterthan95%forheavycompositeMajorana neu-trinosofmassesabove1 TeV)andissuitableforNdecaysthrough

boththegaugeandthecontactinteractions. Thesignalregionfor thesearch forheavy composite Majorananeutrinosis definedby requiringtwoleptons,selectedwithoutspecifyingthecharge,with

invariantmassm>300GeV andatleastonelarge-radiusjet

sat-isfyingthepreviouslydescribedrequirements.Therequirementon m isintroducedinordertoreduce theDYbackgroundandpart

ofthett background,withoutaffectingthesignalacceptance.With thisselection,thetotalefficiencyforeventsenteringthesignal re-gion is expected to be about 50% in the eeqq channel and75% in the μμqq channel, for masses of N greater than 1 TeV and

=9TeV.Wefindthatthetotalsignalefficiencyvariesbyatmost 25%forsignalsamplesproducedwithof1and13 TeV,whileit changeslessthan3%forsignalsamplesgeneratedwithbetween 5 and13 TeV.A shape-based analysisisperformed, searching for evidenceofasignalbyconsideringthedistributionofthemassof the two leptons andthe leading large-radius jet, mJ. This vari-ableprovidesgooddiscrimination betweenthesignalandtheSM backgroundcontributions,ascanbeseeninFig. 4.

5. Backgroundestimation

The dominant background process is top quark pair produc-tion,tt,whichisestimatedtogether withthesingletopquark tW contribution.Thesetwo sourcesofbackgroundare always consid-eredtogether inthis analysisandthe combinationis referred to as tt+tW. The estimation is performed using a control sample indata freeof signalcontamination. Thiscontrol sample consists of qq events in which one lepton is required to be an elec-tron and the other a muon. The acceptanceand efficiency differ betweenmuonsandelectrons,andwefindthatthe overallevent efficiencydependsmoststronglyonthekinematicsoftheleading lepton.We thereforedefinesamplesofseparate anddistinct final states eμJ and μeJ, wherethe first named lepton is the leading one, as control samples for the signal samples eeJ and μμJ, re-spectively.Allotherrequirementsarethesameforboththecontrol andsignalsamples.WehaveverifiedthatthemeeJ andmμμJ dis-tributions arewell-modelledby thecorrespondingmeμJ andmμeJ distributions usingthe MCsamples.Fig. 3showsgood agreement between data and expectation fromMC simulation for the meμJ andthemμeJdistributions.Backgroundsfromprocessesotherthan tt+tW in these control samples are estimated fromsimulation andsubtractedprior tobeingtransferredtothesignalregion.The final tt+tW contribution is estimated from the mass shapes of thedifferentflavourcontrolregionsscaledtothesignalregionsby transfer factors.The transfer factors depend onmJ andare

es-timated in binscorresponding to those of Fig. 3, whichare then usedforthefinalmassdistributionsinthesignalregions.Theyare evaluated usingMC simulationandaccount fordifferencesin ac-ceptances andefficiencies ofselectedeμqq and μeqq eventsof thecontrolregions withrespecttotheselectedeeqqand μμqq eventsofthesignalregions.

The DY process gives rise to another source of background when two leptons are produced together with initial-state radi-ation that results in a jet. This contribution is estimated from the MC simulation normalised to data in the signal-free region around the Z boson mass peak given by 80<M()<100GeV. Inorderto checkthe validityofthemeasured normalization fac-tors for masses above the Z boson mass peak, we compare the data with the MC prediction in the signal-depleted region given by100<M()<300GeV.Wefindthatthenormalisationfactors varyby8%betweenthesetwomassranges,andweusethisvalue to assign a systematicuncertainty. The statisticaland systematic uncertainties ofthe normalisationfactorare then combinedwith thestatisticaluncertaintyoftheDYsimulationtoestimatethe to-talsystematicuncertainty.

Multijet events with at least three jets may enter the signal orcontrolregionforestimatingbackgroundsrelatedtotopquarks if two ofthese jetsare misidentified as leptons. The

contamina-Fig. 3. Dataeventsintheeμqqcontrolregionsusedtoestimatethett+tW contributionintheeeqq(left)andμμqq(right)channels,comparedtotheexpectationsof thebackgroundsimulations.“Other”standsforthecontributionfromW+jetsanddibosonevents.(Forinterpretationofthereferencestocolourinthisfigure,thereaderis referredtothewebversionofthisarticle.)

tion dueto thisprocess is found tobe negligible because ofthe lowrateatwhichjetsaremisidentifiedasleptons.Weverifythis withamethoddevelopedintheCMSsearchforZ-likeresonances inelectronpairormuon pairfinalstates[37].Nonisolatedlepton candidatesselectedfromdataareweightedby acorrectionfactor toextrapolatethefinal contributiontothesignal region.The cor-rectionfactor is the rateofa nonisolated lepton to passthe full selectionandismeasuredfromdataasafunctionof pT andη.

The other SM backgrounds, arising from W+jets and diboson production,are small(∼5% ofthetotal),andtheircontributionis takendirectlyfromMCsimulation.

6. Systematicuncertainties

The systematic uncertainties are taken into account through their effectonthe massdistribution andthe yieldnormalisation. The uncertainty in the calculation of the tt+tW and DY back-grounds is dominated by the statistical uncertainty of the con-trol samples used for the estimations. The contamination from sub dominant backgrounds in these control regions has a negli-gible effect on the systematic uncertainty. The uncertainties re-latedtothebackgroundestimationsvarybetween20and30%(40 and100%)fromthelowest tothehighestmass bininwhichthe tt+tW (DY)processescontribute.Theuncertaintyassociatedwith theestimationofthe W+jetsanddibosonbackgrounds,which to-gether representonlya smallfractionofthe eventsinthe signal region, has a negligible impact on the limit calculation. The un-certainty intheacceptanceassociatedwiththe PDFsisevaluated inaccordancewiththePDF4LHC recommendations[38],usingthe PDF4LHC15 Hessian PDF set with100 eigenvectors. The PDF un-certainty amounts to 10% for theDY backgroundand 4% forthe signal. Uncertainties related to the trigger, and to lepton recon-struction,identification,andisolationefficienciesaremeasuredby dedicatedanalysesusingZ→ events[32,33]andamounton av-erageto 3% (6%) for thebackground and4% (10%) forthe signal intheelectron(muon)channel.The systematicuncertaintyinthe leptonenergyscaleandresolutionare foundtobe approximately 5% (6%) for the background and3% (4%) for the signal. The un-certainty related to jet energy scale amounts to 3% (4%) forthe backgroundoftheeeqq (μμqq)channel, andaround1% forthe

Table 1

Number ofevents observed indata arecompared to the expectedbackground yields and thoseofa hypotheticalheavycomposite Majorana neutrino ofmass 1.5and2.5 TeV,and=9 TeV,givenforallvaluesofmJ(uppertable)andfor mJ>1.4 TeV(lowertable).Theexpectedsignalyieldsarecomputedat LO

ac-curacy.“Other”standsforthecontributionfromW+jetsand dibosonevents.The backgroundandsignalsimulationyieldsaregivenwithbothstatisticaland system-aticuncertainties.Statisticaluncertaintiesgivenas0.0correspondtovaluesmuch smallerthanthesystematicaluncertainty.

Process (all mJ) eeqq

(mean±stat±syst)

μμqq

(mean±stat±syst)

tt+tW 26±4±3 44±6±5 Drell–Yan 22±1±5 30±1±7 Other 3.3±0.8±0.1 4.7±0.9±0.4 Total 51±4±6 80±6±8 Observed 64 88 N(1.5 TeV) 9.7±0.0±0.3 12.8±0.0±1.6 N(2.5 TeV) 2.4±0.0±0.1 3.2±0.0±0.4 Process (mJ>1.4 TeV) eeqq

(mean±stat±syst)

μμqq

(mean±stat±syst)

tt+tW 2.8±1.5±0.9 2.9±1.8±1.3 Drell–Yan 3.2±0.3±2.0 4.3±0.4±2.7 Other 0.36±0.10±0.04 0.25±0.10±0.11 Total 6.4±1.5±2.2 7.5±1.8±3.0 Observed 8 10 N(1.5 TeV) 9.4±0.0±0.3 12.4±0.0±1.6 N(2.5 TeV) 2.4±0.0±0.1 3.2±0.0±0.4

signal regardless of the channel. Uncertainties related to jet en-ergy resolution correspond to 2 and 4% for the background and thesignal,respectively,inbothchannels.Theimperfectmodelling of pileup interactions leads to a systematicuncertainty of about 4% forbackgroundand2%forsignal. Theuncertaintyinthe total integratedluminosityamountsto2.3%forthe2015data[13].

7. Results

Table 1liststheestimatedbackgroundyields,thetotalnumber ofobservedeventsforeachchannelandthenumberofevents

ex-Fig. 4. DistributionofthevariablemJforthedata(blackpoints),theestimatedSMbackgrounds(stackedfilledhistograms),andthesignal(lines)with=9 TeVandmasses

ofNequalto1.5and2.5 TeV,fortheeeqq(left)andtheμμqq(right)channels.“Other”standsforthecontributionfromW+jetsanddibosonevents.Thebackground uncertaintiesarethecombinedstatisticalandsystematicuncertainties.(Forinterpretationofthereferencestocolourinthisfigure,thereaderisreferredtothewebversion ofthisarticle.)

Fig. 5. Theobserved95%CLupperlimits(solidblacklines)onσ(pp→ N)B(N→ qq),obtainedintheanalysisoftheeeqq(left)andtheμμqq(right)finalstates, asafunctionofthemassoftheheavycompositeMajorananeutrino,N.Thecorrespondingexpectedlimitsareshownbythedottedlines,andthebandsrepresentthe expectedvariationofthelimittooneandtwostandarddeviation(s).Thesolidbluecurveindicatesthetheoreticalpredictionofσ(pp→ N)B(N→ qq)for=mN.

Theuncertaintyinthetheoreticalpredictionisderivedbytakingintoaccountthefactorization andnormalizationscales.Thelightredtexturedcurvesgivethetheoretical predictionsforthreevaluesrangingfrom6to12 TeVinstepsof3 TeV.(Forinterpretationofthereferencestocolourinthisfigurelegend,thereaderisreferredtothe webversionofthisarticle.)

pectedfor thesignal, considering =9TeV andtwo hypotheses forthemassesof N: 1.5and2.5 TeV.Table 1 (upper)showsthe

numberof eventsintegrated over all valuesof the reconstructed mass,whileTable 1(lower)showstheagreementforthehigh sen-sitivityregionabove1.4 TeV.

Distributionsof mJ are shownin Fig. 4,where the data are comparedwith theestimated SM backgrounds andtwo different signalhypothesesaresuperimposed.The figuresarefortheeeqq (left)and μμqq (right)channels. Theuncertainties on the back-groundestimation are the combinationof the statistical andthe systematicuncertainties.

The observations are in agreement with the background ex-pectations from the SM. We use a modified frequentist C Ls

cri-terion[39,40]tosetanupperlimitat95%CLontheproductcross sectionforproduction oftheheavy compositeMajorananeutrino

produced in association with a lepton and the branching frac-tion for the N decay to a same-flavour lepton and two quarks,

(pp→ N)B(N→ qq). Wealso set upperlimits onthe

com-positeness scale .The mJ distributions for the MC signal, SM backgrounds, and observed data are used as input in the limit computation together withthesystematicuncertaintiesdiscussed inSection6,whicharetreatedasuncorrelatedamongthebinsof the massdistribution, ifthey are relatedto the background esti-mations,andcorrelatedotherwise.

The observed and expected upper limits on σ(pp→ N)×

B(N→ qq) as a function of the mass of the heavy

compos-ite Majorana neutrino are shown in Fig. 5. The bands represent expected variations ofthe limit to one andtwo standard devia-tion(s). The solid blue curve indicates the theoretical prediction of σ(pp→ N)B(N→ qq) for mN= , while the light red

Fig. 6. Theobserved95%CLlowerlimits(solidblacklines)onthecompositenessscale,obtainedintheanalysisoftheeeqq(left)andtheμμqq(right)finalstates,asa functionofthemassoftheheavycompositeMajorananeutrino,N.Thedottedlinesrepresentthecorrespondingexpectedlimitsandthebands,theexpectedvariationto oneandtwostandarddeviation(s).Thegreyzonerepresentsthephasespace<MN,whichisnotallowedbythemodel.

texturedcurvesshowthesametheoretical predictionforthree

valuesrangingfrom6to12 TeV.Thecorrespondingexclusion lim-its on the compositeness scale  are displayed in Fig. 6. At low N masses, valuesofthe compositenessscale can be excluded

upto 11.5and10.0 TeVin theeeqq and μμqq channel, respec-tively.The sensitivityto decreasesathigher massesofN.For

the case of mN= , the resulting exclusion limits on mN are up to4.60(4.55) TeV inthe eeqq channel and4.70(4.75) TeV in the μμqqchannel,considering theobservation(SMexpectation). When deriving theselimits, we assume that the signal efficiency is independent of. Thishypothesis hasbeen validatedfor sig-nal samples produced with  between 5 and 13 TeV, while for sampleswithlowerthan5 TeVthedifferencecanbeupto25%. Despitethisdifference,thewholeregioninFig. 6remainsexcluded becauseofthemuchhighercrosssection forlower points.We further verify that the upper limits on mN for a given  value varyat mostby 5% comparingthe casesin whichthe MC signal mJdistributionsproducedwithequalto5and13 TeVareused asinputinthelimitcalculation.

8. Summary

Asearchforphysicsbeyondthestandard modelhasbeen per-formedintheframeworkofanewmodel[12]predicting aheavy Majorananeutrino, N,that originatesfrom a composite-fermion

scenario and is produced in association with a matched-flavour charged lepton. The measurement is performed analysing the fi-nalstatewithtwoleptons,selectedwithoutspecifyingthecharge, andatleastonelarge-radiusjet,asignaturenotpreviouslyutilized insearchesforheavy neutrinos.Thedatasetusedcorrespondsto anintegratedluminosityof2.3fb−1 collectedwiththeCMS detec-tor at the LHC in pp collisions at √s=13 TeV. Good agreement betweenthedataandthestandardmodelpredictionisobserved. Upper limits are set at 95% confidence level both on the prod-uct ofthe crosssection σ(pp→ N) andthe branching fraction

B(N→ qq),andonthecompositenessscale,asafunctionof

mN,  being an electron ora muon. Forthe representative case =mN,Nemassesupto4.60 TeVandNμ massesupto4.70 TeV are excluded. This measurement represents the first search that placesconstraintsonthemodeldescribedinRef.[12].

Acknowledgements

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

References

[1] J.C.Pati,A.Salam,J.A.Strathdee,Arequarkscomposite?,Phys.Lett.B59(1975) 265,https://doi.org/10.1016/0370-2693(75)90042-8.

[2] H.Harari,Compositemodelsforquarksandleptons,Phys.Rep.104(1984)159, https://doi.org/10.1016/0370-1573(84)90207-2.

[3] O.W.Greenberg,C.A.Nelson,Compositemodelsofleptons,Phys.Rev.D10 (1974)2567,https://doi.org/10.1103/PhysRevD.10.2567.

[4] H.Terazawa,t-Quarkmasspredictedfromasumrulefor leptonandquark masses,Phys.Rev.D22(1980)2921,https://doi.org/10.1103/PhysRevD.22.2921, Erratum:https://doi.org/10.1103/PhysRevD.41.3541.

[5] E.Eichten,K.D.Lane,M.E.Peskin,Newtestsforquarkandleptonsubstructure, Phys.Rev.Lett.50(1983)811,https://doi.org/10.1103/PhysRevLett.50.811. [6] N.Cabibbo,L.Maiani,Y.Srivastava,AnomalousZdecays:excitedleptons?,Phys.

Lett.B139(1984)459,https://doi.org/10.1016/0370-2693(84)91850-1. [7] U.Baur,M.Spira,P.M.Zerwas,Excitedquarkandleptonproductionathadron

[8] O.Panella,Y.N.Srivastava,Boundsoncompositenessfromneutrinolessdouble betadecay,Phys.Rev.D52(1995)5308,https://doi.org/10.1103/PhysRevD.52. 5308,arXiv:hep-ph/9411224.

[9] O.Panella,C.Carimalo,Y.N.Srivastava,A.Widom,Neutrinolessdoublebeta decaywithcompositeneutrinos,Phys.Rev.D56(1997)5766,https://doi.org/ 10.1103/PhysRevD.56.5766,arXiv:hep-ph/9701251.

[10] O.Panella, C.Carimalo,Y.N.Srivastava,Production oflikesigndileptons in ppcollisionsthroughcompositeMajorana neutrinos,Phys.Rev.D62(2000) 015013,https://doi.org/10.1103/PhysRevD.62.015013,arXiv:hep-ph/9903253. [11] S. Biondini, O. Panella, Leptogenesis and composite heavy neutrinos with

gauge-mediatedinteractions,Eur.Phys.J.C77(2017)644,https://doi.org/10. 1140/epjc/s10052-017-5206-x,arXiv:1707.00844.

[12] R.Leonardi,L.Alunni,F.Romeo,L.Fanò,O.Panella,Huntingforheavy com-positeMajorananeutrinosattheLHC,Eur.Phys.J.C76(2016)593,https://doi. org/10.1140/epjc/s10052-016-4396-y,arXiv:1510.07988.

[13] CMSCollaboration, CMSluminosity measurement for the2015 data taking period,CMSphysicsanalysissummaryCMS-PAS-LUM-15-001,https://cds.cern. ch/record/2138682,2016.

[14] ATLASCollaboration,Searchfor excitedelectronsand muonsin√s=8TeV proton–proton collisions with the ATLAS detector, New J. Phys. 15 (2013) 093011,https://doi.org/10.1088/1367-2630/15/9/093011,arXiv:1308.1364. [15] CMS Collaboration, Search for excited leptons in proton–proton collisions

at √s=8TeV, J. HighEnergy Phys. 03 (2016)125,https://doi.org/10.1007/ JHEP03(2016)125,arXiv:1511.01407.

[16] ATLASCollaboration,Searchforheavyneutrinosandright-handedW bosons

ineventswithtwoleptonsandjetsinpp collisionsat√s=7TeV withthe ATLASdetector,Eur.Phys.J.C72(2012)1, https://doi.org/10.1140/epjc/s10052-012-2056-4,arXiv:1203.5420.

[17] ATLASCollaboration,SearchforheavyMajorananeutrinoswiththeATLAS de-tectorin pp collisions at √s=8TeV, J. HighEnergy Phys. 07 (2015)162, https://doi.org/10.1007/JHEP07(2015)162,arXiv:1506.06020.

[18] CMS Collaboration, Search for heavy neutrinos and W bosons with right-handedcouplingsinproton–protoncollisionsat√s=8TeV,Eur.Phys.J.C74 (2014)1,https://doi.org/10.1140/epjc/s10052-014-3149-z,arXiv:1407.3683. [19] CMSCollaboration,SearchforheavyMajorananeutrinosinμ±μ±+jetsevents

in proton–proton collisions at √s=8TeV, Phys. Lett. B 748 (2015) 144, https://doi.org/10.1016/j.physletb.2015.06.070,arXiv:1501.05566.

[20] CMSCollaboration, Searchfor heavyMajorana neutrinos in e±e±+jets and e±μ±+jets events in proton–proton collisions at √s=8TeV, J. High En-ergyPhys.04(2016)169,https://doi.org/10.1007/JHEP04(2016)169,arXiv:1603. 02248.

[21] CMS Collaboration, Search for heavy neutrinos and third-generation lepto-quarksinfinalstateswithtwohadronicallydecayingτ leptonsandtwojets inproton–protoncollisionsat√s=13TeV,J.HighEnergyPhys.03(2017)77, https://doi.org/10.1007/JHEP03(2017)077,arXiv:1612.01190.

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

[23] A.Belyaev,N.D.Christensen,A.Pukhov,CalcHEP3.4forcolliderphysicswithin andbeyond thestandard model,Comput.Phys. Commun.184(2013)1729, https://doi.org/10.1016/j.cpc.2013.01.014,arXiv:1207.6082.

[24] P.Nason,AnewmethodforcombiningNLOQCDwithshowerMonteCarlo algorithms,J.HighEnergyPhys.11(2004)040, https://doi.org/10.1088/1126-6708/2004/11/040,arXiv:hep-ph/0409146.

[25] S.Frixione,P.Nason,C.Oleari,MatchingNLOQCDcomputationswithparton showersimulations:thePOWHEGmethod,J.HighEnergyPhys.11(2007)070, https://doi.org/10.1088/1126-6708/2007/11/070,arXiv:0709.2092.

[26] S.Alioli,P.Nason,C.Oleari,E.Re,AgeneralframeworkforimplementingNLO calculationsinshowerMonteCarloprograms:thePOWHEGBOX,J.High En-ergyPhys.06(2010)043,https://doi.org/10.1007/JHEP06(2010)043,arXiv:1002. 2581.

[27] J.Alwall,R.Frederix,S.Frixione,V.Hirschi,F.Maltoni,O.Mattelaer,H.S.Shao, T.Stelzer,P.Torrielli,M.Zaro,Theautomatedcomputationoftree-leveland next-to-leading orderdifferentialcross sections,and theirmatching to par-tonshowersimulations,J.HighEnergyPhys.07(2014)079,https://doi.org/10. 1007/JHEP07(2014)079,arXiv:1405.0301.

[28] T.Sjöstrand, S.Ask,J.R. Christiansen,R.Corke, N.Desai,P.Ilten,S.Mrenna, S.Prestel,C.O.Rasmussen,P.Z.Skands,AnintroductiontoPYTHIA8.2, Com-put.Phys.Commun.191(2015)159,https://doi.org/10.1016/j.cpc.2015.01.024, arXiv:1410.3012.

[29] PartondistributionsfortheLHCRunII,J.HighEnergyPhys.04(2015)040, https://doi.org/10.1007/JHEP04(2015)040,arXiv:1410.8849.

[30] CMSCollaboration,Eventgeneratortunesobtainedfromunderlyingeventand multipartonscatteringmeasurements,Eur.Phys.J.C76(2016)155,https://doi. org/10.1140/epjc/s10052-016-3988-x,arXiv:1512.00815.

[31] S. Agostinelli,et al., GEANT4, GEANT4—a simulation toolkit, Nucl. Instrum. MethodsA506(2003)250,https://doi.org/10.1016/S0168-9002(03)01368-8. [32] CMSCollaboration,Performanceofelectronreconstructionandselectionwith

the CMSdetector inproton–proton collisions at √s=8TeV, J. Instrum. 10 (2015) P06005, https://doi.org/10.1088/1748-0221/10/06/P06005, arXiv:1502. 02701.

[33] CMSCollaboration,PerformanceofCMSmuonreconstructioninppcollision events at √s=7TeV, J. Instrum. 7(2012) P10002, https://doi.org/10.1088/ 1748-0221/7/10/P10002,arXiv:1206.4071.

[34] M.Cacciari,G.P.Salam,G.Soyez,FastJetusermanual,Eur.Phys.J.C72(2012) 1896,https://doi.org/10.1140/epjc/s10052-012-1896-2,arXiv:1111.6097. [35] M.Cacciari,G.P.Salam, Dispellingthe N3 _{mythfor the k}

t jet-finder, Phys.

Lett.B641(2006)57,https://doi.org/10.1016/j.physletb.2006.08.037, arXiv:hep-ph/0512210.

[36] CMSCollaboration, Particle-flowreconstructionand globaleventdescription withtheCMSdetector,J.Instrum.12(2017)P10003,https://doi.org/10.1088/ 1748-0221/12/10/P10003,arXiv:1706.04965.

[37] CMS Collaboration, Search for narrow resonances in dilepton mass spec-tra inproton–protoncollisions at √s=13TeV andcombination with8 TeV data,Phys.Lett.B768(2017)57,https://doi.org/10.1016/j.physletb.2017.02.010, arXiv:1609.05391.

[38] J.Butterworth, etal., PDF4LHCrecommendationsfor LHCRun II,J.Phys. G 43(2016)023001,https://doi.org/10.1088/0954-3899/43/2/023001,arXiv:1510. 03865.

[39] A.L.Read,Presentationofsearchresults:theCLstechnique,J.Phys.G28(2002)

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

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

TheCMSCollaboration

A.M. Sirunyan,A. Tumasyan

YerevanPhysicsInstitute,Yerevan,Armenia

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

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

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

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

InstitutfürHochenergiephysik,Wien,Austria

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

InstituteforNuclearProblems,Minsk,Belarus

E.A. De Wolf,X. Janssen, J. Lauwers,M. Van De Klundert, H. Van Haevermaet,P. Van Mechelen,

N. Van Remortel,A. Van Spilbeeck

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

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

P. Van Mulders, I. Van Parijs

VrijeUniversiteitBrussel,Brussel,Belgium

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

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

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

UniversitéLibredeBruxelles,Bruxelles,Belgium

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

W. Verbeke,N. Zaganidis

GhentUniversity,Ghent,Belgium

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

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

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

UniversitéCatholiquedeLouvain,Louvain-la-Neuve,Belgium

N. Beliy

UniversitédeMons,Mons,Belgium

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

CentroBrasileirodePesquisasFisicas,RiodeJaneiro,Brazil

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

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

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

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

UniversidadedoEstadodoRiodeJaneiro,RiodeJaneiro,Brazil

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

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

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

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

InstituteforNuclearResearchandNuclearEnergyofBulgariaAcademyofSciences,Bulgaria

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

UniversityofSofia,Sofia,Bulgaria

W. Fang5, X. Gao5

BeihangUniversity,Beijing,China

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

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

InstituteofHighEnergyPhysics,Beijing,China

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

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

UniversidaddeLosAndes,Bogota,Colombia

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

UniversityofSplit,FacultyofElectricalEngineering,MechanicalEngineeringandNavalArchitecture,Split,Croatia

Z. Antunovic,M. Kovac

UniversityofSplit,FacultyofScience,Split,Croatia

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

InstituteRudjerBoskovic,Zagreb,Croatia

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

UniversityofCyprus,Nicosia,Cyprus

M. Finger6,M. Finger Jr.6

CharlesUniversity,Prague,CzechRepublic

E. Carrera Jarrin

UniversidadSanFranciscodeQuito,Quito,Ecuador

Y. Assran7,8, M.A. Mahmoud9,8,A. Mahrous10

AcademyofScientificResearchandTechnologyoftheArabRepublicofEgypt,EgyptianNetworkofHighEnergyPhysics,Cairo,Egypt

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

NationalInstituteofChemicalPhysicsandBiophysics,Tallinn,Estonia

P. Eerola,J. Pekkanen, M. Voutilainen

DepartmentofPhysics,UniversityofHelsinki,Helsinki,Finland

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

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

HelsinkiInstituteofPhysics,Helsinki,Finland

J. Talvitie,T. Tuuva

LappeenrantaUniversityofTechnology,Lappeenranta,Finland

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

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

A. Rosowsky,M.Ö. Sahin, M. Titov

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

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

R. Granier de Cassagnac,M. Jo, S. Lisniak,A. Lobanov, M. Nguyen, C. Ochando, G. Ortona, P. Paganini,

P. Pigard,S. Regnard, R. Salerno, Y. Sirois,A.G. Stahl Leiton, T. Strebler, Y. Yilmaz, A. Zabi, A. Zghiche

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

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

E. Conte11,X. Coubez, J.-C. Fontaine11, D. Gelé, U. Goerlach,A.-C. Le Bihan, P. Van Hove

S. Gadrat

CentredeCalculdel’InstitutNationaldePhysiqueNucleaireetdePhysiquedesParticules,CNRS/IN2P3,Villeurbanne,France

S. Beauceron,C. Bernet, G. Boudoul, R. Chierici,D. Contardo, B. Courbon, P. Depasse, H. El Mamouni,

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

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

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

T. Toriashvili13

GeorgianTechnicalUniversity,Tbilisi,Georgia

Z. Tsamalaidze6

TbilisiStateUniversity,Tbilisi,Georgia

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

T. Verlage

RWTHAachenUniversity,I.PhysikalischesInstitut,Aachen,Germany

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

R. Fischer,A. Güth, M. Hamer, T. Hebbeker,C. Heidemann, K. Hoepfner, S. Knutzen,M. Merschmeyer,

A. Meyer, P. Millet,S. Mukherjee, M. Olschewski, K. Padeken,T. Pook,M. Radziej, H. Reithler, M. Rieger,

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

RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

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

O. Pooth,A. Stahl14

RWTHAachenUniversity,III.PhysikalischesInstitutB,Aachen,Germany

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

K. Borras15,V. Botta, A. Campbell, P. Connor,C. Contreras-Campana, F. Costanza, C. Diez Pardos,

G. Eckerlin, D. Eckstein, T. Eichhorn, E. Eren, E. Gallo16,J. Garay Garcia, A. Geiser, A. Gizhko,

J.M. Grados Luyando, A. Grohsjean, P. Gunnellini, A. Harb,J. Hauk, M. Hempel17,H. Jung,

A. Kalogeropoulos, M. Kasemann,J. Keaveney, C. Kleinwort, I. Korol,D. Krücker, W. Lange, A. Lelek,

T. Lenz,J. Leonard, K. Lipka,W. Lohmann17,R. Mankel, I.-A. Melzer-Pellmann, A.B. Meyer, G. Mittag,

J. Mnich, A. Mussgiller, E. Ntomari,D. Pitzl, R. Placakyte, A. Raspereza,B. Roland, M. Savitskyi,P. Saxena,

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

O. Zenaiev

DeutschesElektronen-Synchrotron,Hamburg,Germany

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

M. Hoffmann,A. Junkes, R. Klanner, R. Kogler, N. Kovalchuk,S. Kurz, T. Lapsien, I. Marchesini,

D. Marconi,M. Meyer, M. Niedziela, D. Nowatschin, F. Pantaleo14, T. Peiffer, A. Perieanu,C. Scharf,

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

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

UniversityofHamburg,Hamburg,Germany

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

A. Dierlamm, B. Freund,R. Friese,M. Giffels, A. Gilbert,D. Haitz, F. Hartmann14,S.M. Heindl,

U. Husemann,F. Kassel14, S. Kudella, H. Mildner, M.U. Mozer,Th. Müller, M. Plagge, G. Quast,

S. Williamson, C. Wöhrmann, R. Wolf

InstitutfürExperimentelleKernphysik,Karlsruhe,Germany

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

InstituteofNuclearandParticlePhysics(INPP),NCSRDemokritos,AghiaParaskevi,Greece

S. Kesisoglou, A. Panagiotou, N. Saoulidou

NationalandKapodistrianUniversityofAthens,Athens,Greece

I. Evangelou,C. Foudas, P. Kokkas, N. Manthos, I. Papadopoulos,E. Paradas, J. Strologas, F.A. Triantis

UniversityofIoánnina,Ioánnina,Greece

M. Csanad,N. Filipovic, G. Pasztor

MTA-ELTELendületCMSParticleandNuclearPhysicsGroup,EötvösLorándUniversity,Budapest,Hungary

G. Bencze,C. Hajdu, D. Horvath18, F. Sikler,V. Veszpremi, G. Vesztergombi19,A.J. Zsigmond

WignerResearchCentreforPhysics,Budapest,Hungary

N. Beni,S. Czellar, J. Karancsi20,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. Bahinipati21,S. Bhowmik, P. Mal, K. Mandal, A. Nayak22, D.K. Sahoo21, N. Sahoo,S.K. Swain

NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

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

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

PanjabUniversity,Chandigarh,India

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

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

UniversityofDelhi,Delhi,India

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

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

M. Sharan, S. Thakur

SahaInstituteofNuclearPhysics,HBNI,Kolkata,India

P.K. Behera

IndianInstituteofTechnologyMadras,Madras,India

R. Chudasama,D. Dutta, V. Jha, V. Kumar, A.K. Mohanty14, P.K. Netrakanti,L.M. Pant, P. Shukla,A. Topkar

BhabhaAtomicResearchCentre,Mumbai,India

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

S. Banerjee, S. Bhattacharya, S. Chatterjee,P. Das, M. Guchait, Sa. Jain, S. Kumar, M. Maity23,

G. Majumder, K. Mazumdar,T. Sarkar23, N. Wickramage24

TataInstituteofFundamentalResearch-B,Mumbai,India

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

IndianInstituteofScienceEducationandResearch(IISER),Pune,India

S. Chenarani25, E. Eskandari Tadavani,S.M. Etesami25,M. Khakzad, M. Mohammadi Najafabadi,

M. Naseri, S. Paktinat Mehdiabadi26,F. Rezaei Hosseinabadi, B. Safarzadeh27,M. Zeinali

InstituteforResearchinFundamentalSciences(IPM),Tehran,Iran

M. Felcini,M. Grunewald

UniversityCollegeDublin,Dublin,Ireland

M. Abbresciaa,b, C. Calabriaa,b,C. Caputoa,b,A. Colaleoa,D. Creanzaa,c, L. Cristellaa,b,N. De Filippisa,c, M. De Palmaa,b, L. Fiorea,G. Iasellia,c, G. Maggia,c,M. Maggia, G. Minielloa,b, S. Mya,b, S. Nuzzoa,b, A. Pompilia,b,G. Pugliesea,c,R. Radognaa,b,A. Ranieria,G. Selvaggia,b,A. Sharmaa,L. Silvestrisa,14,

R. Vendittia, P. Verwilligena

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

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

G.M. Dallavallea,F. Fabbria, A. Fanfania,b, D. Fasanellaa,b,P. Giacomellia,L. Guiduccia,b, S. Marcellinia, G. Masettia, F.L. Navarriaa,b_{,A. Perrotta}a_{, A.M. Rossi}a,b_{,T. Rovelli}a,b_{, G.P. Siroli}a,b_{,N. Tosi}a,b,14

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,28, G. Sguazzonia, D. Stroma, L. Viliania,b,14

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

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

INFNLaboratoriNazionalidiFrascati,Frascati,Italy

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

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

L. Brianzaa,b, F. Brivioa,b, V. Cirioloa,b, M.E. Dinardoa,b,S. Fiorendia,b, S. Gennaia, A. Ghezzia,b, P. Govonia,b,M. Malbertia,b, S. Malvezzia, R.A. Manzonia,b,D. Menascea,L. Moronia,M. Paganonia,b, K. Pauwelsa,b,D. Pedrinia, S. Pigazzinia,b,29, 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,14, F. Fabozzia,c,F. Fiengaa,b, A.O.M. Iorioa,b,W.A. Khana, L. Listaa,S. Meolaa,d,14,P. Paoluccia,14,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,14,N. Bacchettaa,L. Benatoa,b, A. Bolettia,b, R. Carlina,b,A. Carvalho Antunes De Oliveiraa,b,

P. Checchiaa, M. Dall’Ossoa,b,P. De Castro Manzanoa, T. Dorigoa,S. Fantinela,F. Fanzagoa,

U. Gasparinia,b,F. Gonellaa, A. Gozzelinoa, S. Lacapraraa,M. Margonia,b, A.T. Meneguzzoa,b,

N. Pozzobona,b, P. Ronchesea,b,R. Rossina,b,F. Simonettoa,b, E. Torassaa,M. Zanettia,b, P. Zottoa,b,

G. Zumerlea,b

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

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

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

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

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

K. Androsova, P. Azzurria,14,G. Bagliesia,J. Bernardinia,T. Boccalia,L. Borrello, R. Castaldia, M.A. Cioccia,b,R. Dell’Orsoa, G. Fedia,A. Giassia, M.T. Grippoa,28, F. Ligabuea,c,T. Lomtadzea, L. Martinia,b,A. Messineoa,b,F. Pallaa, A. Rizzia,b, A. Savoy-Navarroa,30, P. Spagnoloa, R. Tenchinia, G. Tonellia,b,A. Venturia, P.G. Verdinia

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

c_{ScuolaNormaleSuperiorediPisa,Pisa,Italy}

L. Baronea,b, F. Cavallaria,M. Cipriania,b, D. Del Rea,b,14, M. Diemoza, S. Gellia,b, E. Longoa,b, F. Margarolia,b, B. Marzocchia,b,P. Meridiania, G. Organtinia,b,R. Paramattia,b,F. Preiatoa,b, S. Rahatloua,b,C. Rovellia, F. Santanastasioa,b

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

N. Amapanea,b,R. Arcidiaconoa,c,14,S. Argiroa,b,M. Arneodoa,c,N. Bartosika,R. Bellana,b, C. Biinoa, N. Cartigliaa,F. Cennaa,b, M. Costaa,b,R. Covarellia,b,A. Deganoa,b,N. Demariaa, B. Kiania,b,

C. Mariottia, S. Masellia,E. Migliorea,b_{, V. Monaco}a,b_{, E. Monteil}a,b_{, M. Monteno}a_{,M.M. Obertino}a,b_, L. Pachera,b,N. Pastronea, M. Pelliccionia, G.L. Pinna Angionia,b,F. Raveraa,b,A. Romeroa,b, M. Ruspaa,c, R. Sacchia,b, K. Shchelinaa,b, V. Solaa,A. Solanoa,b,A. Staianoa,P. Traczyka,b

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

c_{UniversitàdelPiemonteOrientale,Novara,Italy}

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

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

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

KyungpookNationalUniversity,Daegu,RepublicofKorea

A. Lee

ChonbukNationalUniversity,Jeonju,RepublicofKorea

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

ChonnamNationalUniversity,InstituteforUniverseandElementaryParticles,Kwangju,RepublicofKorea

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

HanyangUniversity,Seoul,RepublicofKorea

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

KoreaUniversity,Seoul,RepublicofKorea

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

H.D. Yoo,G.B. Yu

SeoulNationalUniversity,Seoul,RepublicofKorea

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

UniversityofSeoul,Seoul,RepublicofKorea

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

SungkyunkwanUniversity,Suwon,RepublicofKorea

V. Dudenas, A. Juodagalvis,J. Vaitkus

VilniusUniversity,Vilnius,Lithuania

I. Ahmed,Z.A. Ibrahim, M.A.B. Md Ali31,F. Mohamad Idris32,W.A.T. Wan Abdullah, M.N. Yusli,

Z. Zolkapli

NationalCentreforParticlePhysics,UniversitiMalaya,KualaLumpur,Malaysia

H. Castilla-Valdez, E. De La Cruz-Burelo,I. Heredia-De La Cruz33,R. Lopez-Fernandez, J. Mejia Guisao,

A. Sanchez-Hernandez

CentrodeInvestigacionydeEstudiosAvanzadosdelIPN,MexicoCity,Mexico

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

UniversidadIberoamericana,MexicoCity,Mexico

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

BenemeritaUniversidadAutonomadePuebla,Puebla,Mexico

A. Morelos Pineda

UniversidadAutónomadeSanLuisPotosí,SanLuisPotosí,Mexico

D. Krofcheck

P.H. Butler

UniversityofCanterbury,Christchurch,NewZealand

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

NationalCentreforPhysics,Quaid-I-AzamUniversity,Islamabad,Pakistan

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

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

NationalCentreforNuclearResearch,Swierk,Poland

K. Bunkowski, A. Byszuk34,K. Doroba, A. Kalinowski, M. Konecki,J. Krolikowski, M. Misiura,

M. Olszewski,A. Pyskir, M. Walczak

InstituteofExperimentalPhysics,FacultyofPhysics,UniversityofWarsaw,Warsaw,Poland

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

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

LaboratóriodeInstrumentaçãoeFísicaExperimentaldePartículas,Lisboa,Portugal

S. Afanasiev,P. Bunin, M. Gavrilenko,I. Golutvin, I. Gorbunov, A. Kamenev,V. Karjavin, A. Lanev,

A. Malakhov,V. Matveev35,36, V. Palichik,V. Perelygin, S. Shmatov, S. Shulha, N. Skatchkov,V. Smirnov,

N. Voytishin, A. Zarubin

JointInstituteforNuclearResearch,Dubna,Russia

Y. Ivanov,V. Kim37,E. Kuznetsova38, P. Levchenko,V. Murzin, V. Oreshkin, I. Smirnov, V. Sulimov,

L. Uvarov, S. Vavilov, A. Vorobyev

PetersburgNuclearPhysicsInstitute,Gatchina(St.Petersburg),Russia

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

A. Pashenkov,D. Tlisov, A. Toropin

InstituteforNuclearResearch,Moscow,Russia

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

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

InstituteforTheoreticalandExperimentalPhysics,Moscow,Russia

T. Aushev,A. Bylinkin36

MoscowInstituteofPhysicsandTechnology,Moscow,Russia

P. Parygin,D. Philippov,V. Rusinov

NationalResearchNuclearUniversity,‘MoscowEngineeringPhysicsInstitute’(MEPhI),Moscow,Russia

V. Andreev,M. Azarkin36,I. Dremin36, M. Kirakosyan, A. Terkulov

P.N.LebedevPhysicalInstitute,Moscow,Russia

A. Baskakov,A. Belyaev, E. Boos,M. Dubinin39,L. Dudko, A. Ershov, A. Gribushin, V. Klyukhin,

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

V. Blinov40, Y. Skovpen40, D. Shtol40

NovosibirskStateUniversity(NSU),Novosibirsk,Russia

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

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

StateResearchCenterofRussianFederation,InstituteforHighEnergyPhysics,Protvino,Russia

P. Adzic41, P. Cirkovic, D. Devetak,M. Dordevic, J. Milosevic, V. Rekovic

UniversityofBelgrade,FacultyofPhysicsandVincaInstituteofNuclearSciences,Belgrade,Serbia

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

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

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

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

CentrodeInvestigacionesEnergéticasMedioambientalesyTecnológicas(CIEMAT),Madrid,Spain

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

UniversidadAutónomadeMadrid,Madrid,Spain

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

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

UniversidaddeOviedo,Oviedo,Spain

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

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

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

V. Daponte, A. David, M. De Gruttola, A. De Roeck, E. Di Marco42, M. Dobson, B. Dorney,T. du Pree,

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

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

O. Karacheban17,J. Kieseler, H. Kirschenmann, V. Knünz,A. Kornmayer14,M.J. Kortelainen, 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. Milenovic43, F. Moortgat,M. Mulders, H. Neugebauer, S. Orfanelli,L. Orsini, L. Pape,

E. Perez,M. Peruzzi, A. Petrilli, G. Petrucciani,A. Pfeiffer, M. Pierini,A. Racz,T. Reis, G. Rolandi44,

M. Rovere, H. Sakulin, J.B. Sauvan, C. Schäfer, C. Schwick,M. Seidel, M. Selvaggi,A. Sharma, P. Silva,

P. Sphicas45, J. Steggemann,M. Stoye, M. Tosi,D. Treille, A. Triossi, A. Tsirou,V. Veckalns46, G.I. Veres19,

M. Verweij, N. Wardle, W.D. Zeuner

CERN,EuropeanOrganizationforNuclearResearch,Geneva,Switzerland

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

T. Rohe, S.A. Wiederkehr

PaulScherrerInstitut,Villigen,Switzerland

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

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

L. Perrozzi,M. Quittnat, M. Rossini,M. Schönenberger, L. Shchutska, A. Starodumov47, V.R. Tavolaro,

K. Theofilatos,M.L. Vesterbacka Olsson, R. Wallny, A. Zagozdzinska34,D.H. Zhu

InstituteforParticlePhysics,ETHZurich,Zurich,Switzerland

T.K. Aarrestad, C. Amsler48, L. Caminada,M.F. Canelli,A. De Cosa, S. Donato, C. Galloni,A. Hinzmann,

T. Hreus,B. Kilminster, J. Ngadiuba,D. Pinna, G. Rauco, P. Robmann, D. Salerno, C. Seitz, A. Zucchetta

UniversitätZürich,Zurich,Switzerland

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

NationalCentralUniversity,Chung-Li,Taiwan

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

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

NationalTaiwanUniversity(NTU),Taipei,Taiwan

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

ChulalongkornUniversity,FacultyofScience,DepartmentofPhysics,Bangkok,Thailand

A. Adiguzel49,M.N. Bakirci50,F. Boran, S. Cerci51,S. Damarseckin, Z.S. Demiroglu, C. Dozen,

I. Dumanoglu, S. Girgis, G. Gokbulut, Y. Guler,I. Hos52, E.E. Kangal53,O. Kara, A. Kayis Topaksu,

U. Kiminsu,M. Oglakci, G. Onengut54,K. Ozdemir55,B. Tali51, S. Turkcapar,I.S. Zorbakir, C. Zorbilmez

ÇukurovaUniversity,PhysicsDepartment,ScienceandArtFaculty,Adana,Turkey

B. Bilin,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

IstanbulTechnicalUniversity,Istanbul,Turkey

B. Grynyov

InstituteforScintillationMaterialsofNationalAcademyofScienceofUkraine,Kharkov,Ukraine

L. Levchuk,P. Sorokin

NationalScientificCenter,KharkovInstituteofPhysicsandTechnology,Kharkov,Ukraine

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

M. Grimes, G.P. Heath, H.F. Heath,J. Jacob, L. Kreczko, C. Lucas, D.M. Newbold61, S. Paramesvaran,

A. Poll, 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, E. Olaiya, D. Petyt, C.H. Shepherd-Themistocleous, A. Thea,I.R. Tomalin, T. Williams

RutherfordAppletonLaboratory,Didcot,UnitedKingdom

M. Baber,R. Bainbridge, 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, P. Dunne, A. Elwood, D. Futyan,Y. Haddad,

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

C. Seez,A. Shtipliyski, S. Summers,A. Tapper, K. Uchida, M. Vazquez Acosta63, T. Virdee14,

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

ImperialCollege,London,UnitedKingdom

J.E. Cole, P.R. Hobson, A. Khan,P. Kyberd, I.D. Reid, P. Symonds, L. Teodorescu, M. Turner

BrunelUniversity,Uxbridge,UnitedKingdom

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

BaylorUniversity,Waco,USA

R. Bartek, A. Dominguez

CatholicUniversityofAmerica,WashingtonDC,USA

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, J. Hakala,U. Heintz, J.M. Hogan, K.H.M. Kwok,E. Laird, G. Landsberg,

Z. Mao, M. Narain, S. Piperov,S. Sagir, R. Syarif, D. Yu

BrownUniversity,Providence,USA

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

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

J. Pilot, S. Shalhout, M. Shi,J. Smith, M. Squires, 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, 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, P. Jandir,

E. Kennedy, F. Lacroix,O.R. Long, M. Olmedo Negrete, M.I. Paneva, A. Shrinivas,W. Si, H. Wei,

S. Wimpenny,B.R. Yates

UniversityofCalifornia,Riverside,Riverside,USA

J.G. Branson, G.B. Cerati, S. Cittolin, M. Derdzinski,B. Hashemi, A. Holzner, D. Klein,G. Kole, V. Krutelyov,

J. Letts, I. Macneill,M. Masciovecchio, D. Olivito, S. Padhi, M. Pieri, M. Sani, V. Sharma, S. Simon,

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, C. George,

F. Golf, L. Gouskos,J. Gran, R. Heller, J. Incandela,S.D. Mullin, A. Ovcharova,H. Qu, J. Richman, D. Stuart,

I. Suarez,J. Yoo

UniversityofCalifornia,SantaBarbara–DepartmentofPhysics,SantaBarbara,USA

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

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