Constraints on the Higgs boson width from off-shell production and decay to Z-boson pairs

Constraints on the Higgs boson width from

off-shell production and decay to Z-boson pairs

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Citation

Khachatryan, V. et al. “Constraints on the Higgs Boson Width from

Off-Shell Production and Decay to Z-Boson Pairs.” Physics Letters B

736 (September 2014): 64–85 © 2014 Elsevier B.V.

As Published

http://dx.doi.org/10.1016/J.PHYSLETB.2014.06.077

Publisher

Elsevier

Version

Final published version

Citable link

http://hdl.handle.net/1721.1/115365

Terms of Use

Attribution 4.0 International (CC BY 4.0)

Contents lists available atScienceDirect

Physics

Letters

B

Constraints

on

the

Higgs

boson

width

from

off-shell

production

and

decay

to

Z-boson

pairs

.CMSCollaboration CERN,Switzerland

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

Articlehistory: Received14May2014

Receivedinrevisedform12June2014 Accepted30June2014

Availableonline3July2014 Editor: M.Doser Keywords: CMS Physics Higgs Diboson Properties

ConstraintsarepresentedonthetotalwidthoftherecentlydiscoveredHiggsboson,ΓH,usingitsrelative

on-shell and off-shell production and decay rates to apair of Z bosons, where one Z boson decays to an electron ormuon pair,and the other to an electron, muon,or neutrino pair. The analysis is based onthe data collectedbythe CMS experiment atthe LHCin 2011and 2012, corresponding to integratedluminositiesof5.1 fb−1atacenter-of-massenergy√s=7 TeV and19.7 fb−1at√s=8 TeV. Asimultaneousmaximumlikelihoodfittothemeasuredkinematicdistributionsneartheresonancepeak and abovetheZ-bosonpairproductionthresholdleadstoanupperlimitontheHiggsbosonwidthof

ΓH<22 MeV ata95%confidencelevel,whichis5.4timestheexpectedvalueinthestandardmodelat

themeasuredmassofmH=125.6 GeV.

©2014TheAuthors.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/3.0/).FundedbySCOAP3_.

The discovery of a new boson consistent with the standard model (SM) Higgs boson by the ATLAS and CMS Collaborations wasrecentlyreported[1–3].Themassofthenewboson(mH)was measuredtobenear125 GeV,andthespin-paritypropertieswere furtherstudiedbybothexperiments,favoring thescalar,JPC₌₀++_, hypothesis [4–7].The measurements werefound tobe consistent withasinglenarrowresonance,andanupperlimitof3.4 GeV ata 95%confidencelevel(CL)onitsdecaywidth(ΓH)wasreportedby theCMSexperimentinthefour-leptondecaychannel[7].Adirect width measurement at the resonance peak is limitedby experi-mental resolution,and is onlysensitive to valuesfar larger than theexpectedwidthofaround4 MeV fortheSMHiggsboson[8,9]. It was recently proposed [10] to constrain the Higgs boson width using its off-shell production and decay to two Z bosons awayfromtheresonancepeak[11].Inthedominantgluonfusion productionmode the off-shellproduction cross section isknown tobe sizable.Thisarisesfroman enhancement inthedecay am-plitudefromthevicinityoftheZ-bosonpairproductionthreshold. A further enhancement comes, in gluon fusion production, from the top-quarkpair productionthreshold. The zero-width approx-imationis inadequate andthe ratioof the off-shellcross section above2mZtotheon-shellsignalisoftheorderof8%[11,12]. Fur-therdevelopmentstothemeasurementoftheHiggsbosonwidth wereproposedinRefs.[13,14].

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

The gluon fusion production cross section depends on ΓH throughtheHiggsbosonpropagator

dσgg→H→ZZ dm2_ZZ ∼ g2 ggHgHZZ2 (m2_ZZ−m2_H)2_+m2 HΓH2 , (1)

where gggH and gHZZ are the couplings of the Higgs boson to gluonsandZbosons,respectively.Integratingeitherinasmall re-gion around mH,or above themass thresholdmZZ>2mZ,where (mZZ−mH) ΓH,thecrosssectionsare,respectively,

σ_ggon-shell_→H→ZZ∗∼ g2 ggHgHZZ2 mHΓH andσ_ggoff-shell_→H∗_→ZZ∼ g2 ggHg2HZZ (2mZ)2 . (2)

FromEq.(2),itisclearthatameasurementoftherelativeoff-shell andon-shellproductionintheH→ZZ channelprovidesdirect in-formationonΓH,aslongasthecouplingratiosremainunchanged, i.e. the gluon fusion production is dominated by the top-quark loopandtherearenonewparticlescontributing.Inparticular,the on-shell production crosssection is unchanged undera common scaling ofthe squared product of the couplings and of the total width ΓH, while the off-shell production cross section increases linearlywiththisscalingfactor.

The dominant contribution for the production of a pair of Z bosons comesfromthequark-initiatedprocess, qq→ZZ, the dia-gramforwhichisdisplayedinFig. 1(left).Thegluon-induced dibo-son productioninvolvesthe gg→ZZ continuumbackground pro-ductionfromtheboxdiagrams, asillustrated inFig. 1(center). An

http://dx.doi.org/10.1016/j.physletb.2014.06.077

0370-2693/©2014TheAuthors.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/3.0/).Fundedby SCOAP3_.

Fig. 1. LowestordercontributionstothemainZZ productionprocesses:(left)quark-initiatedproduction,qq→ZZ,(center)ggcontinuumbackgroundproduction,gg→ZZ, and(right)Higgs-mediatedggproduction,gg→H→ZZ,thesignal.

exampleofthesignalproductiondiagramisshowninFig. 1(right). Theinterference betweenthetwo gluon-inducedcontributions is significantathighmZZ [15],andistakenintoaccountinthe anal-ysisoftheoff-shellsignal.

Vectorbosonfusion(VBF)production,whichcontributesatthe levelofabout7% totheon-shell crosssection, isexpectedto in-crease above 2mZ. The above formalism describing the ratio of off-shellandon-shellcrosssectionsisapplicable tothe VBF pro-duction mode. In this analysis we constrain the fraction of VBF productionusing theproperties ofthe eventsin theon-shell re-gion.TheothermainHiggsbosonproductionmechanisms,ttH and VH(V=Z,W), which contribute at the level ofabout 5% to the on-shellsignal,arenot expectedto produceasignificantoff-shell contributionasthey are suppressedat highmass [8,9]. Theyare thereforeneglectedintheoff-shellanalysis.

InthisLetter,wepresentconstraintsontheHiggsbosonwidth usingitsoff-shellproductionanddecaytoZ-bosonpairs,inthe fi-nalstateswhereoneZbosondecaystoanelectronoramuonpair andtheother toeitheran electronoramuonpair,H→ZZ→4 (4 channel),orapairofneutrinos,H→ZZ→22ν (22ν chan-nel).RelyingontheobservedHiggsbosonsignal intheresonance peakregion[7],thesimultaneousmeasurementofthesignalinthe high-mass region leads to constraints on the Higgs boson width ΓHinthe4 decaychannel. The22ν decaychannel,which ben-efitsfromahigherbranchingfraction[16,17],isusedinthe high-massregiontofurtherincreasethesensitivitytotheHiggsboson width. The analysisisperformed forthe tree-levelHVVcoupling ofascalarHiggsboson,consistentwithourobservations[4,7],and implicationsfortheanomalousHVVinteractionsarediscussed.The Higgsboson mass is set to the measured value in the 4 decay channelofmH=125.6 GeV [7]andthe Higgsbosonwidthisset tothecorrespondingexpectedvalueintheSMofΓ_HSM=4.15 MeV [8,9].

Themeasurementis basedonpp collision datacollectedwith the CMS detector at the LHC in 2011, corresponding to an in-tegrated luminosity of 5.1 fb−1 at the center-of-mass energy of

√

s=7 TeV (4 channel), and in 2012, corresponding to an in-tegrated luminosity of 19.7 fb−1 at √s=8 TeV (4 and 22ν

channels). The CMS detector, described in detail elsewhere [18], providesexcellentresolutionforthemeasurementofelectronand muontransversemomenta(pT)overawiderange.Thesignal can-didatesareselectedusingwell-identifiedandisolatedprompt lep-tons. Theonlineselection andeventreconstruction are described elsewhere[2,3,7,16].The analysispresented hereisbased onthe sameeventselectionasusedinRefs. [7,16].

The analysis in the 4 channel uses the four-lepton invari-antmassdistribution aswell asamatrix elementlikelihood dis-criminanttoseparate theZZcomponentsoriginatingfrom gluon-and quark-initiated processes. We define the on-shell signal re-gion as105.6<m4<140.6 GeV and the off-shell signal region

asm4>220 GeV.Theanalysisinthe22ν channelreliesonthe

transversemassdistributionmT,

m2_T=  pT,22+m22+  E_Tmiss2+m22 2 −pT,2+ EmissT 2 , (3)

wherepT,2andm2arethemeasuredtransversemomentumand

invariant mass of the dilepton system, respectively. The missing transverseenergy,Emiss_T ,isdefinedasthemagnitudeofthe trans-versemomentumimbalanceevaluatedasthenegative ofthe vec-torialsumoftransversemomentaofallthereconstructedparticles intheevent.Inthe22ν channel,theoff-shellsignalregionis de-finedasmT>180 GeV.Thechoiceoftheoff-shellregionsinboth channels is done prior to looking at the data, based on the ex-pectedsensitivity.

Simulated Monte Carlo (MC) samples of gg→4 and gg→ 22ν events are generated at leading order (LO) in perturbative quantum chromodynamics (QCD), including theHiggs boson sig-nal, the continuum background, and the interference contribu-tionsusingrecentversionsoftwodifferentMCgenerators, gg2VV 3.1.5 [11,19] and mcfm 6.7 [20], inorder to cross-check theoret-ical inputs. The QCD renormalizationand factorizationscales are settomZZ/2 (dynamicscales)andMSTW2008LOparton distribu-tionfunctions(PDFs)[21]are used.Higher-order QCDcorrections for the gluon fusion signal process are knownto an accuracy of next-to-next-to-leading order(NNLO) and next-to-next-to-leading logarithmsforthetotalcrosssection[8,9]andtoNNLOasa func-tion ofmZZ [14]. Thesecorrection factors tothe LOcrosssection (K factors)aretypicallyintherangeof2.0to2.5.Afterthe applica-tionofthemZZ-dependentKfactors,theeventyieldisnormalized to thecross section fromRefs. [8,9]. Forthe gg→ZZ continuum background,althoughnoexactcalculationexistsbeyondLO,ithas beenrecentlyshown[22] thatthesoftcollinearapproximation is abletodescribethebackgroundcrosssectionandthereforethe in-terference termatNNLO.Following thiscalculation,we assignto theLObackgroundcrosssection(and,consequently,tothe interfer-encecontribution)aKfactorequaltothatusedforthesignal[14]. The limited theoretical knowledge of the backgroundK factor at NNLOis takenintoaccount byincludingan additionalsystematic uncertainty,theimpactofwhichonthemeasurementis neverthe-lesssmall.

Vector bosonfusion eventsare generated with phantom[23]. Off-shellandinterferenceeffectswiththenonresonantproduction areincludedatLOinthesesimulations.Theeventyieldis normal-ized tothecross sectionatNNLO QCD andnext-to-leadingorder (NLO)electroweak(EW)[8,9]accuracy,withanormalizationfactor showntobeindependentofmZZ.

In order to parameterize and validate the distributions of all thecomponentsforbothgluonfusion andVBFprocesses,specific simulatedsamplesarealsoproducedthatdescribeonlythesignal or the continuum background, as well as several scenarios with scaledcouplingsandwidth.Fortheon-shellanalysis,signalevents are generated eitherwith powheg [24–27] productionat NLO in QCD and JHUGen [28,29] decay (gluon fusion and VBF), or with pythia_{6.4[30](VHandttH production).}

Inboththe4and22ν channelsthedominantbackgroundis qq→ZZ.WeassumeSMproductionratesforthisbackground,the contributionof whichisevaluated by powheg simulation atNLO inQCD[31].Next-to-leadingorderEWcalculations[32,33],which predict negative and mZZ-dependent corrections to the qq→ZZ processforon-shellZ-bosonpairs,aretakenintoaccount.

Allsimulatedeventsundergopartonshoweringand hadroniza-tionusing pythia.AsisdoneinRef.[7]forLOsamples,theparton

Fig. 2. Distributionofthe four-leptoninvariantmass inthe range100<m4< 800 GeV.Pointsrepresentthe data,filled histogramsthe expectedcontributions fromthereducible(Z+X)andqq backgrounds,andfromthesumofthegluon fusion(gg)andvectorbosonfusion(VV)processes,includingtheHiggsboson me-diatedcontributions.Theinsetshowsthedistributioninthelowmassregionafter aselectionrequirementontheMELAlikelihooddiscriminantDkin

bkg>0.5[7].Inthis region,thecontributionofthettH andVH productionprocessesisaddedtothe dominantgluonfusionandVBFcontributions.

showeringsettingsaretunedtoapproximatelyreproducetheZZpT spectrumpredictedatNNLO fortheHiggsbosonproduction[34]. GeneratedeventsarethenprocessedwiththedetailedCMS detec-tor simulationbased on Geant4 [35,36], andreconstructed using thesamealgorithmsasusedfortheobservedevents.

Thefinalstate inthe4 channelischaracterizedbyfour well-identifiedandisolatedleptons formingtwopairsofopposite-sign andsame-flavor leptonsconsistentwithtwoZ bosons.This chan-nelbenefitsfromaprecisereconstructionofallfinal stateleptons andfromaverylowinstrumentalbackground.Theeventselection and the reducible background evaluation are performed follow-ing themethods described in Ref.[7].Afterthe selection, the4 data sample is dominated by the quark-initiated qq→ZZ→4 (qq→4)andgg→4productions.

Fig. 2presentsthemeasuredm4distributionoverthefullmass

range,m4>100 GeV, together with the expected SM

contribu-tions. The gg→4 contribution is clearly visible inthe on-shell signalregionandattheZ-bosonpairproductionthreshold,above the qq→4 background.The observed distribution is consistent withthe expectationfromSM processes. We observe223 events in the off-shell signal region, while we expect 217.6±9.5 from SMprocesses,includingtheSMHiggsbosonsignal.

Inordertoenhance thesensitivitytotheggproductioninthe off-shellregion,alikelihooddiscriminantDggisused,which char-acterizestheeventtopology inthe4center-of-massframe using theobservables (mZ1,mZ2,Ω) foragivenvalue ofm4,whereΩ denotes the five angles defined in Ref. [28]. The discriminant is builtfromtheprobabilitiesP_totgg andP_bkgqq foraneventtooriginate fromeitherthegg→4 ortheqq→4 process.Weusethe ma-trixelementlikelihoodapproach(MELA)[2,29]fortheprobability computation using the mcfm matrix elements for both gg→4 andqq→4processes.Theprobability P_totgg forthegg→4 pro-cess includes the signal (P_siggg), the background (P_bkggg), and their

Fig. 3. Distributionsof(top)the four-leptoninvariant mass afteraselection re-quirementontheMELAlikelihooddiscriminantDgg>0.65,and(bottom)theDgg likelihooddiscriminantform4>330 GeV inthe4channel.Pointsrepresentthe data,filledhistogramstheexpectedcontributionsfromthereducible(Z+X)and qq backgrounds,andfromthegluonfusion(gg)andvectorbosonfusion(VV)SM processes(includingtheHiggsbosonmediatedcontributions).Thedashedline cor-respondstothetotalexpectedyieldforaHiggsbosonwidthandasquaredproduct ofthecouplingsscaledbyafactor10withrespecttotheirSMvalues.Inthetop plot,thebinsizevariesfrom20to85 GeV andthelastbinincludesallentrieswith massesabove800 GeV.

interference(P_intgg),asintroducedforthediscriminantcomputation inRef.[37].Thediscriminantisdefinedas

Dgg= P gg tot Pgg tot+P qq bkg =  1+ P qq bkg a×P_siggg+√a×P_intgg+P_bkggg −1 , (4)

where the parameter a is the strength of the unknown anoma-lousgg contributionwithrespecttotheexpectedSMcontribution (a=1).Weseta=10 inthedefinitionofDggaccordingtothe ex-pectedsensitivity.Studiesshowthattheexpectedsensitivitydoes not changesubstantially whena isvaried upordownbyafactor of2. Itshould bestressed thatfixing the parametera to agiven value onlyaffects the sensitivityof the analysis. Tosuppress the dominantqq→4backgroundintheon-shellregion,theanalysis also employs a MELA likelihood discriminant Dkin_bkg based on the JHUGenand mcfm matrix elementcalculationsforthesignaland

Table 1

Expectedandobservednumbersofeventsinthe4and22νchannelsingg-enrichedregions,definedbym4≥ 330 GeV andDgg>0.65 (4),andbymT>350 GeV andEmissT >100 GeV (22ν).Thenumbersofexpected eventsaregivenseparatelyfortheggandVBFprocesses,andforaSMHiggsboson(ΓH= ΓHSM)andaHiggs bosonwidthandsquaredproductofthecouplingsscaledbyafactor10withrespecttotheirSMvalues.The unphysicalexpectedcontributionsforthesignalandbackgroundcomponentsarealsoreportedseparately,forthe ggandVBFprocesses.Forbothprocesses,thesumofthesignalandbackgroundcomponentsdiffersfromthe totalduetothenegativeinterferences.Thequoteduncertaintiesincludeonlythesystematicsources.

4 22ν (a) Total gg (ΓH= ΓHSM) 1.8±0.3 9.6±1.5 gg Signal component (ΓH= ΓHSM) 1.3±0.2 4.7±0.6 gg Background component 2.3±0.4 10.8±1.7 (b) Total gg (ΓH=10× ΓHSM) 9.9±1.2 39.8±5.2 (c) Total VBF (ΓH= ΓHSM) 0.23±0.01 0.90±0.05 VBF signal component (ΓH= ΓHSM) 0.11±0.01 0.32±0.02 VBF background component 0.35±0.02 1.22±0.07 (d) Total VBF (ΓH=10× ΓHSM) 0.77±0.04 2.40±0.14 (e) qq background 9.3±0.7 47.6±4.0 (f) Other backgrounds 0.05±0.02 35.1±4.2 (a+c+e+f) Total expected (ΓH= ΓHSM) 11.4±0.8 93.2±6.0 (b+d+e+f) Total expected (ΓH=10× ΓHSM) 20.1±1.4 124.9±7.8 Observed 11 91

thebackground, asillustrated by the insetin Fig. 2 andused in Ref.[7].

Asanillustration,Fig. 3(top)presentsthe4invariantmass dis-tribution forthe off-shell signal region (m4>220 GeV) and for

Dgg>0.65.Theexpectedcontributionsfromtheqq→4and re-duciblebackgrounds,aswellasforthetotalgluonfusion(gg)and vectorbosonfusion(VV)contributions,includingtheHiggsboson signal,are shown. Thedistribution of thelikelihood discriminant Dgg form4>330 GeV isshowninFig. 3(bottom),together with

the expected contributions from the SM. The expected m4 and

Dggdistributionsforthesumofalltheprocesses,withaHiggs bo-sonwidthΓH=10× ΓHSM andarelativecrosssectionwithrespect to theSM cross section equal to unity inboth gluon fusion and VBFproductionmodes(μ =μggH=μVBF=1),arealsopresented, showingtheenhancementarisingfromthescalingofthesquared productofthecouplings.The expectedandobservedeventyields intheoff-shellgg-enrichedregiondefinedbym4≥330 GeV and

Dgg>0.65 arereportedinTable 1.

The22ν analysisisperformedonthe8 TeV datasetonly.The finalstateinthe22νchannelischaracterizedbytwo oppositely-charged leptons of the same flavor compatible with a Z boson, together witha large Emiss_T fromthe undetectable neutrinos. We requireEmiss_T >80 GeV.Theeventselection andbackground esti-mationisperformedasdescribed inRef.[16],withtheexception thatthejetcategoriesdefinedinRef.[16]areheregroupedintoa singlecategory, i.e.theanalysisisperformedinaninclusiveway. ThemT distributionintheoff-shellsignal region (mT>180 GeV) isshown in Fig. 4. The expected andobserved event yields in a gg-enrichedregiondefinedbymT>350 GeV and EmissT >100 GeV arereportedinTable 1.

Systematic uncertainties comprise experimental uncertainties onthe signal efficiencyand backgroundyield evaluation, aswell asuncertaintiesonthesignalandbackgroundfromtheoretical pre-dictions.SincethemeasurementisperformedinwidemZZregions, thereare sources ofsystematic uncertainties that only affectthe totalnormalizationandothers that affectboth thenormalization andtheshapeoftheobservablesusedinthisanalysis.Inthe4 fi-nalstate,onlythelattertypeofsystematicuncertaintyaffectsthe measurementofΓH,sincenormalizationuncertaintieschangethe on-shellandoff-shellyieldsbythesameamount.

Fig. 4. Distributionofthetransversemassinthe22νchannel.Pointsrepresentthe data,filledhistogramstheexpectedcontributionsfromthebackgrounds,andfrom thegluonfusion (gg)and vectorbosonfusion (VV)SMprocesses (includingthe Higgs-mediatedcontributions).Thedashedlinecorrespondstothetotalexpected yieldforaHiggsbosonwidthandasquaredproductofthecouplingsscaledbya factor10withrespecttotheirSMvalues.Thebinsizevariesfrom80to210 GeV andthelastbinincludesallentrieswithtransversemassesabove1 TeV.

Amongthesignaluncertainties,experimentalsystematic uncer-tainties are evaluated from observed events for the trigger effi-ciency (1.5%), and combined object reconstruction, identification andisolationefficiencies(3–4%formuons,5–11%forelectrons)[7]. Inthe22ν final state,theeffectsoftheleptonmomentumscale (1–2%)andjetenergyscale(1%)aretakenintoaccountand prop-agated to the evaluation of Emiss_T . The uncertainty in the b-jet veto(1–3%) isestimatedfromsimulationusing correctionfactors fortheb-taggingandb-misidentificationefficienciesasmeasured fromthedijetandtt decaycontrolsamples[38].

TheoreticaluncertaintiesfromQCDscalesintheqq background contribution are within 4–10% depending on mZZ [7]. An addi-tional uncertainty of 2–6% is included to account for missing higher order contributions with respect to a full NLO QCD and NLO EW evaluation. The systematic uncertainty in the

normal-ization of the reducible backgrounds is evaluated following the methodsdescribed inRefs. [7,16].Inthe22ν channel,forwhich these contributions are not negligible at high mass, the estima-tionfromcontrolsamplesfortheZ+jets andforthesumofthe tt, tW and WW contributions leads to uncertainties of 25% and 15%inthe respectivebackgroundyields.Theoretical uncertainties inthe highmass contributionfrom thegluon-induced processes, whichaffectboththenormalizationandtheshape,areespecially importantinthisanalysis(inparticularforthesignaland interfer-encecontributionsthatarescaledbylargefactors).However,these uncertainties partiallycancelwhenmeasuring simultaneouslythe yieldfromthesameprocessintheon-shellsignalregion.The re-mainingmZZ-dependentuncertainties intheQCD renormalization andfactorization scales are derived usingthe K factor variations fromRef. [14],correspondingtoa factoroftwo upordownfrom thenominalmZZ/2 values,andamountto 2–4%.Forthegg→ZZ continuumbackgroundproduction,weassigna10%additional un-certainty on the K factor,following Ref. [22] andtaking into ac-countthedifferentmassrangesandselectionsonthespecificfinal state. This uncertainty also affects the interferencewith the sig-nal. The PDF uncertainties are estimated following Refs. [39,40] by changingthe NLO PDF set fromMSTW2008toCT10 [41] and NNPDF2.1[42],andtheresidualcontributionisabout1%.Forthe VBF processes, nosignificant mZZ-dependence is found regarding theQCDscales andPDF uncertainties,whichare ingeneralmuch smallerthanforthegluonfusionprocesses[8,9].Inthe22νfinal state,additional uncertaintieson theyield arisingfromthe theo-reticaldescription ofthepartonshower andunderlyingeventare takenintoaccount(6%).

Weperform a simultaneousunbinned maximumlikelihoodfit ofa signal-plus-background model to the measured distributions in the 4 and 22ν channels. In the 4 channel the analysis is performedin the on-shell and off-shell signal regions defined above. In the on-shell region, a three-dimensional distribution



x= (m4,Dbkgkin,pT4orDjet) isanalyzed,followingthe methodol-ogydescribedinRef.[7],wherethequantityDjetisadiscriminant usedtoseparateVBFfromgluonfusionproduction.Intheoff-shell region,atwo-dimensional distributionx= (m4,Dgg)is analyzed. Inthe22ν channel,onlytheoff-shellHiggsbosonproductionis analyzed,usingthex=mT distribution.

The probability distribution functions are built using the full detector simulation or data control regions, and are defined for the signal, the background, orthe interferencebetween the two contributions,Psig,Pbkg,orPint,respectively,asafunctionofthe observablesx discussedabove.Severalproductionmechanismsare consideredforthesignalandthebackground,suchasgluonfusion (gg), VBF, and quark-antiquark annihilation (qq). The total prob-ability distribution function for the off-shell region includes the interferenceoftwocontributionsineachproductionprocess: Poff-shell tot (x)=  μggH× (ΓH/Γ0)×P_siggg(x) + μggH× (ΓH/Γ0)×P_intgg(x)+P_bkggg(x)  +μVBF× (ΓH/Γ0)×PsigVBF(x) + μVBF× (ΓH/Γ0)×PintVBF(x)+PbkgVBF(x)  +P_bkgqq(x)+ . . . (5)

Thelistofbackgroundprocessesisextendedbeyondthosequoted dependingonthe finalstate (Z+X,top,W+jets,WW,WZ).The parameters μggH and μVBF are the scale factors which modify the signal strength with respect to the reference parameteriza-tionineachproductionmechanismindependently.Theparameter (ΓH/Γ0) is the scale factor which modifies the observed width

Fig. 5. Scanofthenegativelog-likelihood,−2lnL,asafunctionofΓHfor the combinedfitofthe4and22ν channels(bluethicklines),forthe 4channel aloneintheoff-shellandon-shellregions(darkredlines),andforthe22νchannel intheoff-shellregionand4channelintheon-shellregion(lightredlines).The solidlinesrepresenttheobservedvalues,thedottedlinestheexpectedvalues.(For interpretationofthereferencestocolorinthisfigurelegend,thereaderisreferred tothewebversionofthisarticle.)

withrespect tothe Γ0 value used inthereference parameteriza-tion.

Intheon-shellregion,theparameterizationincludesthesmall contribution of the ttH and VH Higgs boson production mecha-nisms, whichare relatedto the gluon fusion and VBF processes, respectively, because either the quark or the vector boson cou-pling to the Higgs boson is in common among those processes. Interferenceeffectsare negligibleintheon-shellregion.Thetotal probability distributionfunctionfortheon-shellregion iswritten as Pon-shell tot (x)=μggH×  Pgg sig(x)+P ttH sig(x)  +μVBF  PVBF sig (x)+PsigVH(x)  +Pqq bkg(x)+P gg bkg(x)+ . . . (6) The above parameterizations inEqs. (5, 6) are performedforthe tree-level HVV coupling ofa scalarHiggs boson, consistent with our observations [4,7]. We find that the presence of anomalous couplingsintheHVVinteractionwouldleadtoenhancedoff-shell productionandamorestringentconstraintonthewidth. Itis ev-ident thatthe parameterizationin Eq.(5)relies onthe modeling ofthegluonfusionproductionwiththedominanttop-quarkloop, thereforenopossiblenewparticlesareconsideredintheloop. Fur-therdiscussioncanalsobefoundinRefs.[43–45].

ThethreeparametersΓH, μggH,and μVBFareleftunconstrained inthefit.The μggH and μVBF fittedvaluesarefoundtobe almost identicaltothoseobtainedinRef.[7].Systematicuncertaintiesare includedasnuisanceparametersandaretreatedaccordingto the frequentist paradigm [46]. The shapesand normalizations of the signal and of each background component are allowed to vary within their uncertainties, and thecorrelations in the sources of systematicuncertaintyaretakenintoaccount.

The fit results are shown in Fig. 5 as scans of the negative log-likelihood,−2lnL,asa functionofΓH. Combiningthe two channels a limit is observed (expected) on the total width of ΓH<22 MeV (33 MeV)ata95% CL,whichis5.4(8.0) timesthe expected value in the SM. The best fit value and 68% CL inter-valcorrespondto ΓH=1.8+₋71..78 MeV.The resultofthe4analysis

aloneis an observed (expected)limit of ΓH<33 MeV (42 MeV) ata 95% CL,which is8.0(10.1) times theSM value, andthe re-sultoftheanalysiscombiningthe 4 on-shelland22ν off-shell regionsisΓH<33 MeV (44 MeV)ata95%CL,whichis8.1(10.6) timesthe SM value. The bestfit valuesand 68% CLintervals are ΓH=1.9+₋111.9.7MeV andΓH=1.8₋+112.8.4 MeV forthe4analysisand fortheanalysiscombiningthe 4 on-shell and22ν off-shell re-gions,respectively.

Theexpectedlimitforthetwochannelscombinedwithout in-cludingthesystematicuncertainties isΓH<28 MeV ata 95%CL. Theeffectofsystematicuncertainties isdrivenbythe22ν chan-nelwithlargerexperimentaluncertaintiesinsignalefficienciesand background estimation from control samples in data, while the resultinthe4channelislargelydominatedbythestatistical un-certainty.

The statistical compatibility of the observed results with the expectation under the SM hypothesis corresponds to a p-value of 0.24. The statistical coverage of the results obtained in the likelihood scan has also been tested with the Feldman–Cousins approach[47] forthecombinedanalysis leadingto consistent al-thoughslightlytighterconstraints.Theanalysisinthe4 channel hasalsobeenperformedinaone-dimensionalfitusingeitherm4

orDgg andconsistentresultsarefound.Theexpectedlimit with-out using theMELA likelihood discriminant Dgg is 40% larger in the4channel.

Insummary,wehavepresentedconstraintson thetotalHiggs bosonwidthusingitsrelativeon-shellandoff-shellproductionand decayratestofourleptonsortwoleptonsandtwoneutrinos.The analysisisbasedonthe2011and2012datasetscorrespondingto integratedluminosities of5.1 fb−1 at √s=7 TeV and 19.7 fb−1 at √s=8 TeV. The four-lepton analysis uses the measured in-variant mass distribution near the peak and above the Z-boson pairproductionthreshold,aswell asa likelihooddiscriminant to separate thegluon fusionZZproduction fromtheqq→ZZ back-ground,while thetwo-lepton plustwo-neutrinooff-shellanalysis reliesonthe transversemassdistribution. Thepresentedanalysis determinestheindependentcontributionsofthegluonfusionand VBFproductionmechanismsfromthedataintheon-shellregion. Itreliesneverthelessonthe knowledgeofthecouplingratios be-tweentheoff-shellandon-shellproduction,i.e.thedominanceof thetopquarkloopinthegluonfusionproductionmechanismand theabsenceofnewparticlecontributionintheloop.Thepresence ofanomalous couplingsintheHVVinteractionwouldleadto en-hancedoff-shellproductionandwouldmakeourconstrainttighter. Thecombinedfit ofthe4 and22ν channelsleads to anupper limit onthe Higgsboson widthof ΓH<22 MeV at a 95% confi-dencelevel,whichis5.4timestheexpectedwidthoftheSMHiggs boson.Thisresultimprovesbymorethantwoordersofmagnitude upon previous experimental constraints onthe new bosondecay widthfromthedirectmeasurementattheresonancepeak. Acknowledgements

We wish to thankour theoretician colleagues andin particu-larFabrizioCaolafor providingthe theoreticaluncertainty inthe gg→ZZ background K factor, Tobias Kasprzik for providing the numerical calculations on the EW corrections for the qq→ZZ backgroundprocess,GiampieroPassarinoforhiscalculationsofthe

mZZ-dependent K factor and its variations with renormalization and factorization scales, and Marco Zaro for checking the inde-pendenceonmZZ ofhigher-ordercorrectionsinVBFprocesses.We alsogratefullyacknowledgeAlessandroBallestrero,JohnCampbell, KeithEllis,StefanoForte,NikolasKauer,KirillMelnikov,andCiaran Williamsfor their helpin optimizingthe MonteCarlogenerators forthisanalysis.

WecongratulateourcolleaguesintheCERNaccelerator depart-ments for the excellent performance of the LHC and thank the technicalandadministrative staffsatCERN andatother CMS in-stitutes for their contributions to the success of the CMS effort. Inaddition,wegratefullyacknowledgethecomputingcenters and personneloftheWorldwideLHCComputingGridfordeliveringso effectivelythe computinginfrastructureessential to ouranalyses. Finally, we acknowledge the enduring support for the construc-tionandoperation oftheLHC andtheCMSdetectorprovidedby the following funding agencies: BMWF and FWF(Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIEN-CIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER, SF0690030s09andERDF(Estonia);AcademyofFinland,MEC,and HIP(Finland);CEAandCNRS/IN2P3(France);BMBF,DFG,andHGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India);IPM(Iran); SFI(Ireland);INFN (Italy); NRF andWCU (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portu-gal);JINR(Dubna);MON,RosAtom,RASandRFBR(Russia);MESTD (Serbia);SEIDIandCPAN(Spain);SwissFundingAgencies (Switzer-land); NSC (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thai-land);TUBITAKandTAEK(Turkey);NASUandSFFR(Ukraine);STFC (UnitedKingdom);DOEandNSF(USA).

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CMSCollaboration

V. Khachatryan,A.M. Sirunyan, A. Tumasyan

YerevanPhysicsInstitute,Yerevan,Armenia

W. Adam, T. Bergauer, M. Dragicevic,J. Erö, C. Fabjan1,M. Friedl, R. Frühwirth1,V.M. Ghete, C. Hartl, N. Hörmann, J. Hrubec, M. Jeitler1, W. Kiesenhofer,V. Knünz, M. Krammer1, I. Krätschmer,D. Liko, I. Mikulec,D. Rabady2, B. Rahbaran, H. Rohringer,R. Schöfbeck, J. Strauss,A. Taurok,

W. Treberer-Treberspurg,W. Waltenberger, C.-E. Wulz1 InstitutfürHochenergiephysikderOeAW,Wien,Austria

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

S. Alderweireldt, M. Bansal, S. Bansal, T. Cornelis,E.A. De Wolf,X. Janssen, A. Knutsson,S. Luyckx,

S. Ochesanu,B. Roland, R. Rougny, M. Van De Klundert, H. Van Haevermaet,P. Van Mechelen,

N. Van Remortel,A. Van Spilbeeck

F. Blekman,S. Blyweert, J. D’Hondt,N. Daci, N. Heracleous, J. Keaveney,S. Lowette, M. Maes,A. Olbrechts, Q. Python, D. Strom, S. Tavernier,W. Van Doninck, P. Van Mulders, G.P. Van Onsem,I. Villella

VrijeUniversiteitBrussel,Brussel,Belgium

C. Caillol, B. Clerbaux, G. De Lentdecker, D. Dobur, L. Favart, A.P.R. Gay, A. Grebenyuk,A. Léonard, A. Mohammadi, L. Perniè2,T. Reis, T. Seva, L. Thomas, C. Vander Velde, P. Vanlaer,J. Wang

UniversitéLibredeBruxelles,Bruxelles,Belgium

V. Adler,K. Beernaert, L. Benucci, A. Cimmino,S. Costantini, S. Crucy, S. Dildick,A. Fagot, G. Garcia, J. Mccartin,A.A. Ocampo Rios, D. Ryckbosch, S. Salva Diblen,M. Sigamani, N. Strobbe, F. Thyssen, M. Tytgat,E. Yazgan, N. Zaganidis

GhentUniversity,Ghent,Belgium

S. Basegmez, C. Beluffi3, G. Bruno,R. Castello, A. Caudron, L. Ceard, G.G. Da Silveira,C. Delaere,

T. du Pree,D. Favart,L. Forthomme, A. Giammanco4,J. Hollar, P. Jez, M. Komm,V. Lemaitre, C. Nuttens, D. Pagano,L. Perrini, A. Pin, K. Piotrzkowski, A. Popov5,L. Quertenmont, M. Selvaggi, M. Vidal Marono, J.M. Vizan Garcia

UniversitéCatholiquedeLouvain,Louvain-la-Neuve,Belgium

N. Beliy,T. Caebergs, E. Daubie, G.H. Hammad UniversitédeMons,Mons,Belgium

W.L. Aldá Júnior, G.A. Alves,L. Brito,M. Correa Martins Junior, T. Dos Reis Martins, M.E. Pol CentroBrasileirodePesquisasFisicas,RiodeJaneiro,Brazil

W. Carvalho,J. Chinellato6, A. Custódio, E.M. Da Costa, D. De Jesus Damiao,C. De Oliveira Martins, S. Fonseca De Souza, H. Malbouisson,D. Matos Figueiredo, L. Mundim, H. Nogima,W.L. Prado Da Silva, J. Santaolalla,A. Santoro, A. Sznajder,E.J. Tonelli Manganote6, A. Vilela Pereira

UniversidadedoEstadodoRiodeJaneiro,RiodeJaneiro,Brazil

C.A. Bernardesb, T.R. Fernandez Perez Tomeia,E.M. Gregoresb,P.G. Mercadanteb,S.F. Novaesa, Sandra S. Padulaa

a

UniversidadeEstadualPaulista,SãoPaulo,Brazil

b_{UniversidadeFederaldoABC,SãoPaulo,Brazil}

A. Aleksandrov, V. Genchev2, P. Iaydjiev, A. Marinov,S. Piperov, M. Rodozov,G. Sultanov, M. Vutova InstituteforNuclearResearchandNuclearEnergy,Sofia,Bulgaria

A. Dimitrov,I. Glushkov, R. Hadjiiska, V. Kozhuharov,L. Litov, B. Pavlov,P. Petkov UniversityofSofia,Sofia,Bulgaria

J.G. Bian,G.M. Chen, H.S. Chen, M. Chen, R. Du,C.H. Jiang, D. Liang,S. Liang,R. Plestina7, J. Tao,

X. Wang,Z. Wang

InstituteofHighEnergyPhysics,Beijing,China

C. Asawatangtrakuldee, Y. Ban,Y. Guo, Q. Li, W. Li, S. Liu,Y. Mao, S.J. Qian, D. Wang,L. Zhang, W. Zou StateKeyLaboratoryofNuclearPhysicsandTechnology,PekingUniversity,Beijing,China

C. Avila,L.F. Chaparro Sierra, C. Florez, J.P. Gomez, B. Gomez Moreno,J.C. Sanabria UniversidaddeLosAndes,Bogota,Colombia

N. Godinovic, D. Lelas,D. Polic, I. Puljak TechnicalUniversityofSplit,Split,Croatia

Z. Antunovic, M. Kovac UniversityofSplit,Split,Croatia

V. Brigljevic,K. Kadija, J. Luetic, D. Mekterovic, L. Sudic InstituteRudjerBoskovic,Zagreb,Croatia

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

M. Bodlak,M. Finger, M. Finger Jr.8 CharlesUniversity,Prague,CzechRepublic

Y. Assran9, A. Ellithi Kamel10,M.A. Mahmoud11, A. Radi12,13

AcademyofScientificResearchandTechnologyoftheArabRepublicofEgypt,EgyptianNetworkofHighEnergyPhysics,Cairo,Egypt M. Kadastik, M. Murumaa, M. Raidal, A. Tiko

NationalInstituteofChemicalPhysicsandBiophysics,Tallinn,Estonia P. Eerola, G. Fedi,M. Voutilainen DepartmentofPhysics,UniversityofHelsinki,Helsinki,Finland

J. Härkönen,V. Karimäki, R. Kinnunen, M.J. Kortelainen, T. Lampén, K. Lassila-Perini,S. Lehti, T. Lindén, P. Luukka, T. Mäenpää,T. Peltola, E. Tuominen, J. Tuominiemi,E. Tuovinen, L. Wendland

HelsinkiInstituteofPhysics,Helsinki,Finland T. Tuuva

LappeenrantaUniversityofTechnology,Lappeenranta,Finland

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

DSM/IRFU,CEA/Saclay,Gif-sur-Yvette,France

S. Baffioni,F. Beaudette, P. Busson, C. Charlot, T. Dahms, M. Dalchenko,L. Dobrzynski, N. Filipovic, A. Florent,R. Granier de Cassagnac, M. Machet, L. Mastrolorenzo, P. Miné, C. Mironov, I.N. Naranjo, M. Nguyen, C. Ochando, P. Paganini,R. Salerno, J.b. Sauvan, Y. Sirois,C. Veelken, Y. Yilmaz, A. Zabi LaboratoireLeprince-Ringuet,EcolePolytechnique,IN2P3-CNRS,Palaiseau,France

J.-L. Agram14, J. Andrea, A. Aubin, D. Bloch,J.-M. Brom, E.C. Chabert,C. Collard, E. Conte14, J.-C. Fontaine14,D. Gelé, U. Goerlach, C. Goetzmann,A.-C. Le Bihan, P. Van Hove

InstitutPluridisciplinaireHubertCurien,UniversitédeStrasbourg,UniversitédeHauteAlsaceMulhouse,CNRS/IN2P3,Strasbourg,France S. Gadrat

CentredeCalculdel’InstitutNationaldePhysiqueNucleaireetdePhysiquedesParticules,CNRS/IN2P3,Villeurbanne,France

S. Beauceron,N. Beaupere, G. Boudoul2,E. Bouvier, S. Brochet, C.A. Carrillo Montoya, J. Chasserat, R. Chierici,D. Contardo2,P. Depasse,H. El Mamouni, J. Fan, J. Fay, S. Gascon, M. Gouzevitch, B. Ille, T. Kurca, M. Lethuillier, L. Mirabito,S. Perries, J.D. Ruiz Alvarez,D. Sabes, L. Sgandurra,V. Sordini, M. Vander Donckt, P. Verdier, S. Viret,H. Xiao

Z. Tsamalaidze8

InstituteofHighEnergyPhysicsandInformatization,TbilisiStateUniversity,Tbilisi,Georgia

C. Autermann,S. Beranek, M. Bontenackels, M. Edelhoff,L. Feld, O. Hindrichs, K. Klein, A. Ostapchuk, A. Perieanu,F. Raupach, J. Sammet,S. Schael, H. Weber, B. Wittmer, V. Zhukov5

RWTHAachenUniversity,I.PhysikalischesInstitut,Aachen,Germany

M. Ata, E. Dietz-Laursonn,D. Duchardt, M. Erdmann, R. Fischer,A. Güth, T. Hebbeker,C. Heidemann, K. Hoepfner,D. Klingebiel,S. Knutzen, P. Kreuzer,M. Merschmeyer, A. Meyer, P. Millet,M. Olschewski, K. Padeken,P. Papacz, H. Reithler,S.A. Schmitz,L. Sonnenschein, D. Teyssier,S. Thüer, M. Weber RWTHAachenUniversity,III.PhysikalischesInstitutA,Aachen,Germany

V. Cherepanov, Y. Erdogan,G. Flügge, H. Geenen, M. Geisler, W. Haj Ahmad, F. Hoehle,B. Kargoll, T. Kress,Y. Kuessel, J. Lingemann2,A. Nowack, I.M. Nugent,L. Perchalla, O. Pooth, A. Stahl

RWTHAachenUniversity,III.PhysikalischesInstitutB,Aachen,Germany

I. Asin,N. Bartosik, J. Behr,W. Behrenhoff, U. Behrens,A.J. Bell, M. Bergholz15,A. Bethani, K. Borras, A. Burgmeier,A. Cakir,L. Calligaris, A. Campbell, S. Choudhury, F. Costanza, C. Diez Pardos,S. Dooling, T. Dorland,G. Eckerlin, D. Eckstein, T. Eichhorn, G. Flucke, J. Garay Garcia, A. Geiser, P. Gunnellini, J. Hauk, G. Hellwig,M. Hempel, D. Horton, H. Jung, A. Kalogeropoulos,M. Kasemann, P. Katsas,

J. Kieseler, C. Kleinwort,D. Krücker, W. Lange, J. Leonard,K. Lipka, A. Lobanov,W. Lohmann15,B. Lutz, R. Mankel, I. Marfin,I.-A. Melzer-Pellmann, A.B. Meyer, J. Mnich, A. Mussgiller, S. Naumann-Emme, A. Nayak,O. Novgorodova, F. Nowak,E. Ntomari, H. Perrey,D. Pitzl, R. Placakyte, A. Raspereza, P.M. Ribeiro Cipriano,E. Ron, M.Ö. Sahin,J. Salfeld-Nebgen, P. Saxena, R. Schmidt15,

T. Schoerner-Sadenius,M. Schröder, C. Seitz,S. Spannagel, A.D.R. Vargas Trevino, R. Walsh, C. Wissing DeutschesElektronen-Synchrotron,Hamburg,Germany

M. Aldaya Martin,V. Blobel, M. Centis Vignali, A.r. Draeger,J. Erfle, E. Garutti, K. Goebel, M. Görner, J. Haller, M. Hoffmann,R.S. Höing, H. Kirschenmann,R. Klanner, R. Kogler, J. Lange,T. Lapsien, T. Lenz, I. Marchesini,J. Ott, T. Peiffer, N. Pietsch, T. Pöhlsen, D. Rathjens, C. Sander,H. Schettler, P. Schleper, E. Schlieckau,A. Schmidt, M. Seidel, J. Sibille16,V. Sola, H. Stadie,G. Steinbrück, D. Troendle, E. Usai, L. Vanelderen

UniversityofHamburg,Hamburg,Germany

C. Barth,C. Baus, J. Berger,C. Böser, E. Butz, T. Chwalek, W. De Boer,A. Descroix, A. Dierlamm, M. Feindt,F. Frensch, M. Giffels, F. Hartmann2, T. Hauth2,U. Husemann, I. Katkov5,A. Kornmayer2, E. Kuznetsova, P. Lobelle Pardo, M.U. Mozer,Th. Müller, A. Nürnberg, G. Quast, K. Rabbertz, F. Ratnikov, S. Röcker,H.J. Simonis, F.M. Stober,R. Ulrich, J. Wagner-Kuhr, S. Wayand, T. Weiler, R. Wolf

InstitutfürExperimentelleKernphysik,Karlsruhe,Germany

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

InstituteofNuclearandParticlePhysics(INPP),NCSRDemokritos,AghiaParaskevi,Greece A. Panagiotou,N. Saoulidou, E. Stiliaris

UniversityofAthens,Athens,Greece

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

G. Bencze,C. Hajdu, P. Hidas,D. Horvath17, F. Sikler,V. Veszpremi, G. Vesztergombi18, A.J. Zsigmond WignerResearchCentreforPhysics,Budapest,Hungary

N. Beni, S. Czellar, J. Karancsi19,J. Molnar, J. Palinkas, Z. Szillasi InstituteofNuclearResearchATOMKI,Debrecen,Hungary

P. Raics, Z.L. Trocsanyi,B. Ujvari UniversityofDebrecen,Debrecen,Hungary

S.K. Swain

NationalInstituteofScienceEducationandResearch,Bhubaneswar,India

S.B. Beri, V. Bhatnagar,N. Dhingra, R. Gupta, U. Bhawandeep, A.K. Kalsi, M. Kaur, M. Mittal, N. Nishu, J.B. Singh

PanjabUniversity,Chandigarh,India

Ashok Kumar, Arun Kumar,S. Ahuja, A. Bhardwaj, B.C. Choudhary,A. Kumar, S. Malhotra,M. Naimuddin,

K. Ranjan,V. Sharma

UniversityofDelhi,Delhi,India

S. Banerjee, S. Bhattacharya, K. Chatterjee,S. Dutta, B. Gomber, Sa. Jain, Sh. Jain,R. Khurana, A. Modak, S. Mukherjee,D. Roy, S. Sarkar, M. Sharan

SahaInstituteofNuclearPhysics,Kolkata,India

A. Abdulsalam, D. Dutta, S. Kailas,V. Kumar, A.K. Mohanty2, L.M. Pant, P. Shukla,A. Topkar BhabhaAtomicResearchCentre,Mumbai,India

T. Aziz, S. Bhowmik20,R.M. Chatterjee, S. Ganguly,S. Ghosh, M. Guchait21, A. Gurtu22, G. Kole, S. Kumar, M. Maity20,G. Majumder, K. Mazumdar, G.B. Mohanty, B. Parida,K. Sudhakar,

N. Wickramage23

TataInstituteofFundamentalResearch- EHEP,Mumbai,India S. Banerjee, R.K. Dewanjee, S. Dugad TataInstituteofFundamentalResearch- HECR,Mumbai,India

H. Bakhshiansohi,H. Behnamian, S.M. Etesami24, A. Fahim25, R. Goldouzian, A. Jafari,M. Khakzad, M. Mohammadi Najafabadi, M. Naseri, S. Paktinat Mehdiabadi, B. Safarzadeh26, M. Zeinali

InstituteforResearchinFundamentalSciences(IPM),Tehran,Iran

M. Felcini,M. Grunewald

UniversityCollegeDublin,Dublin,Ireland

M. Abbresciaa,b_{, L. Barbone}a,b_{,C. Calabria}a,b_{,S.S. Chhibra}a,b_{,A. Colaleo}a_{,D. Creanza}a,c_,

N. De Filippisa,c, M. De Palmaa,b,L. Fiorea,G. Iasellia,c,G. Maggia,c,M. Maggia, S. Mya,c, S. Nuzzoa,b, A. Pompilia,b,G. Pugliesea,c,R. Radognaa,b,2, G. Selvaggia,b, L. Silvestrisa,2,G. Singha,b, R. Vendittia,b, P. Verwilligena, G. Zitoa

a_{INFNSezionediBari,Bari,Italy} b

UniversitàdiBari,Bari,Italy

c_{PolitecnicodiBari,Bari,Italy}

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

S. Marcellinia, G. Masettia,2, A. Montanaria, F.L. Navarriaa,b,A. Perrottaa, F. Primaveraa,b, A.M. Rossia,b, T. Rovellia,b, G.P. Sirolia,b,N. Tosia,b, R. Travaglinia,b

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

S. Albergoa,b, G. Cappelloa,M. Chiorbolia,b,S. Costaa,b,F. Giordanoa,2,R. Potenzaa,b,A. Tricomia,b, C. Tuvea,b

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

G. Barbaglia,V. Ciullia,b_{,C. Civinini}a_{, R. D’Alessandro}a,b_{, E. Focardi}a,b_{,E. Gallo}a_{, S. Gonzi}a,b_,

V. Goria,b,2,P. Lenzia,b,M. Meschinia,S. Paolettia, G. Sguazzonia, A. Tropianoa,b a_{INFNSezionediFirenze,Firenze,Italy}

b_{UniversitàdiFirenze,Firenze,Italy}

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

F. Ferroa, M. Lo Veterea,b, E. Robuttia,S. Tosia,b a_{INFNSezionediGenova,Genova,Italy}

b_{UniversitàdiGenova,Genova,Italy}

M.E. Dinardoa,b, S. Fiorendia,b,2, S. Gennaia,2,R. Gerosa2, A. Ghezzia,b,P. Govonia,b,M.T. Lucchinia,b,2, S. Malvezzia, R.A. Manzonia,b, A. Martellia,b, B. Marzocchi,D. Menascea,L. Moronia,M. Paganonia,b, D. Pedrinia,S. Ragazzia,b,N. Redaellia, T. Tabarelli de Fatisa,b

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

S. Buontempoa, N. Cavalloa,c,S. Di Guidaa,d,2, F. Fabozzia,c,A.O.M. Iorioa,b, L. Listaa,S. Meolaa,d,2, M. Merolaa, P. Paoluccia,2

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

P. Azzia, N. Bacchettaa, D. Biselloa,b, A. Brancaa,b,R. Carlina,b,P. Checchiaa, M. Dall’Ossoa,b, T. Dorigoa,U. Dossellia, M. Galantia,b,F. Gasparinia,b,U. Gasparinia,b,P. Giubilatoa,b,

A. Gozzelinoa, K. Kanishcheva,c,S. Lacapraraa, M. Margonia,b, A.T. Meneguzzoa,b, J. Pazzinia,b, N. Pozzobona,b, P. Ronchesea,b,F. Simonettoa,b, E. Torassaa,M. Tosia,b, P. Zottoa,b, A. Zucchettaa,b, G. Zumerlea,b

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

M. Gabusia,b,S.P. Rattia,b, C. Riccardia,b,P. Salvinia,P. Vituloa,b a_{INFNSezionediPavia,Pavia,Italy}

b_{UniversitàdiPavia,Pavia,Italy}

M. Biasinia,b,G.M. Bileia,D. Ciangottinia,b, L. Fanòa,b,P. Laricciaa,b,G. Mantovania,b, M. Menichellia, F. Romeoa,b_{,A. Saha}a_{,A. Santocchia}a,b_{, A. Spiezia}a,b,2

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

K. Androsova,27,P. Azzurria,G. Bagliesia,J. Bernardinia,T. Boccalia,G. Broccoloa,c,R. Castaldia,

T. Lomtadzea, L. Martinia,b, A. Messineoa,b,C.S. Moona,28, F. Pallaa,2, A. Rizzia,b, A. Savoy-Navarroa,29, A.T. Serbana,P. Spagnoloa,P. Squillaciotia,27,R. Tenchinia, G. Tonellia,b,A. Venturia,

P.G. Verdinia, C. Vernieria,c,2 a_{INFNSezionediPisa,Pisa,Italy}

b_{UniversitàdiPisa,Pisa,Italy}

c_{ScuolaNormaleSuperiorediPisa,Pisa,Italy}

L. Baronea,b,F. Cavallaria, G. D’imperioa,b,D. Del Rea,b,M. Diemoza, M. Grassia,b, C. Jordaa,E. Longoa,b,F. Margarolia,b,P. Meridiania, F. Michelia,b,2, S. Nourbakhsha,b, G. Organtinia,b,R. Paramattia, S. Rahatloua,b,C. Rovellia, F. Santanastasioa,b,

L. Soffia,b,2, P. Traczyka,b a_{INFNSezionediRoma,Roma,Italy} b_{UniversitàdiRoma,Roma,Italy}

N. Amapanea,b, R. Arcidiaconoa,c,S. Argiroa,b,2, M. Arneodoa,c, R. Bellana,b, C. Biinoa,N. Cartigliaa, S. Casassoa,b,2, M. Costaa,b, A. Deganoa,b,N. Demariaa,L. Fincoa,b,C. Mariottia, S. Masellia,

E. Migliorea,b,V. Monacoa,b,M. Musicha,M.M. Obertinoa,c,2, G. Ortonaa,b,L. Pachera,b,N. Pastronea, M. Pelliccionia,G.L. Pinna Angionia,b, A. Potenzaa,b,A. Romeroa,b, M. Ruspaa,c,R. Sacchia,b,

A. Solanoa,b_{, A. Staiano}a_{, U. Tamponi}a

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

c_{UniversitàdelPiemonteOrientale(Novara),Torino,Italy}

S. Belfortea,V. Candelisea,b,M. Casarsaa, F. Cossuttia,G. Della Riccaa,b, B. Gobboa, C. La Licataa,b, M. Maronea,b,D. Montaninoa,b,A. Schizzia,b,2,T. Umera,b, A. Zanettia

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

T.J. Kim

ChonbukNationalUniversity,Chonju,Korea

S. Chang, A. Kropivnitskaya,S.K. Nam KangwonNationalUniversity,Chunchon,Korea

D.H. Kim,G.N. Kim, M.S. Kim,D.J. Kong, S. Lee, Y.D. Oh,H. Park, A. Sakharov, D.C. Son KyungpookNationalUniversity,Daegu,Korea

J.Y. Kim, S. Song

ChonnamNationalUniversity,InstituteforUniverseandElementaryParticles,Kwangju,Korea

S. Choi, D. Gyun,B. Hong, M. Jo,H. Kim, Y. Kim,B. Lee, K.S. Lee, S.K. Park,Y. Roh KoreaUniversity,Seoul,Korea

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

Y. Choi,Y.K. Choi, J. Goh,D. Kim, E. Kwon, J. Lee, H. Seo,I. Yu SungkyunkwanUniversity,Suwon,Korea

A. Juodagalvis VilniusUniversity,Vilnius,Lithuania

J.R. Komaragiri, M.A.B. Md Ali

H. Castilla-Valdez,E. De La Cruz-Burelo, I. Heredia-de La Cruz30,R. Lopez-Fernandez, A. Sanchez-Hernandez

CentrodeInvestigacionydeEstudiosAvanzadosdelIPN,MexicoCity,Mexico S. Carrillo Moreno, F. Vazquez Valencia UniversidadIberoamericana,MexicoCity,Mexico

I. Pedraza, H.A. Salazar Ibarguen BenemeritaUniversidadAutonomadePuebla,Puebla,Mexico E. Casimiro Linares, A. Morelos Pineda UniversidadAutónomadeSanLuisPotosí,SanLuisPotosí,Mexico D. Krofcheck

UniversityofAuckland,Auckland,NewZealand P.H. Butler,S. Reucroft

UniversityofCanterbury,Christchurch,NewZealand

A. Ahmad, M. Ahmad, Q. Hassan,H.R. Hoorani, S. Khalid, W.A. Khan, T. Khurshid,M.A. Shah, M. Shoaib NationalCentreforPhysics,Quaid-I-AzamUniversity,Islamabad,Pakistan

H. Bialkowska,M. Bluj31,B. Boimska, T. Frueboes,M. Górski, M. Kazana, K. Nawrocki,

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

NationalCentreforNuclearResearch,Swierk,Poland

G. Brona,K. Bunkowski, M. Cwiok,W. Dominik,K. Doroba, A. Kalinowski,M. Konecki, J. Krolikowski,

M. Misiura, M. Olszewski, W. Wolszczak

InstituteofExperimentalPhysics,FacultyofPhysics,UniversityofWarsaw,Warsaw,Poland

P. Bargassa,C. Beirão Da Cruz E Silva, P. Faccioli, P.G. Ferreira Parracho,M. Gallinaro, F. Nguyen, J. Rodrigues Antunes,J. Seixas, J. Varela, P. Vischia

LaboratóriodeInstrumentaçãoeFísicaExperimentaldePartículas,Lisboa,Portugal

S. Afanasiev,P. Bunin,M. Gavrilenko,I. Golutvin, I. Gorbunov, A. Kamenev,V. Karjavin, V. Konoplyanikov, A. Lanev,A. Malakhov,V. Matveev32, P. Moisenz, V. Palichik,V. Perelygin, S. Shmatov, N. Skatchkov, V. Smirnov,A. Zarubin

JointInstituteforNuclearResearch,Dubna,Russia

V. Golovtsov,Y. Ivanov, V. Kim33,P. Levchenko, V. Murzin,V. Oreshkin, I. Smirnov, V. Sulimov,L. Uvarov, S. Vavilov, A. Vorobyev,An. Vorobyev

PetersburgNuclearPhysicsInstitute,Gatchina(St.Petersburg),Russia

Yu. Andreev,A. Dermenev,S. Gninenko, N. Golubev, M. Kirsanov, N. Krasnikov, A. Pashenkov, D. Tlisov, A. Toropin

InstituteforNuclearResearch,Moscow,Russia

V. Epshteyn,V. Gavrilov, N. Lychkovskaya,V. Popov, G. Safronov, S. Semenov, A. Spiridonov, V. Stolin, E. Vlasov,A. Zhokin

V. Andreev,M. Azarkin, I. Dremin, M. Kirakosyan, A. Leonidov, G. Mesyats, S.V. Rusakov, A. Vinogradov

P.N.LebedevPhysicalInstitute,Moscow,Russia

A. Belyaev,E. Boos, V. Bunichev, M. Dubinin34, L. Dudko,A. Ershov, A. Gribushin,V. Klyukhin, O. Kodolova,I. Lokhtin, S. Obraztsov,S. Petrushanko,V. Savrin

SkobeltsynInstituteofNuclearPhysics,LomonosovMoscowStateUniversity,Moscow,Russia

I. Azhgirey,I. Bayshev,S. Bitioukov, V. Kachanov, A. Kalinin, D. Konstantinov, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, L. Tourtchanovitch,S. Troshin, N. Tyurin, A. Uzunian,A. Volkov

StateResearchCenterofRussianFederation,InstituteforHighEnergyPhysics,Protvino,Russia P. Adzic35, M. Ekmedzic,J. Milosevic,V. Rekovic UniversityofBelgrade,FacultyofPhysicsandVincaInstituteofNuclearSciences,Belgrade,Serbia

J. Alcaraz Maestre, C. Battilana,E. Calvo, M. Cerrada,M. Chamizo Llatas, N. Colino, B. De La Cruz, A. Delgado Peris,D. Domínguez Vázquez, 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,G. Merino, E. Navarro De Martino,A. Pérez-Calero Yzquierdo, J. Puerta Pelayo,

A. Quintario Olmeda, I. Redondo,L. Romero,M.S. Soares CentrodeInvestigacionesEnergéticasMedioambientalesyTecnológicas(CIEMAT),Madrid,Spain C. Albajar, J.F. de Trocóniz, M. Missiroli, D. Moran UniversidadAutónomadeMadrid,Madrid,Spain

H. Brun, J. Cuevas,J. Fernandez Menendez, S. Folgueras, I. Gonzalez Caballero, L. Lloret Iglesias UniversidaddeOviedo,Oviedo,Spain

J.A. Brochero Cifuentes, I.J. Cabrillo, A. Calderon, J. Duarte Campderros,M. Fernandez, G. Gomez, A. Graziano, A. Lopez Virto,J. Marco, R. Marco,C. Martinez Rivero, F. Matorras, F.J. Munoz Sanchez, J. Piedra Gomez, T. Rodrigo,A.Y. Rodríguez-Marrero,A. Ruiz-Jimeno, L. Scodellaro,I. Vila,

R. Vilar Cortabitarte

InstitutodeFísicadeCantabria(IFCA),CSIC–UniversidaddeCantabria,Santander,Spain

D. Abbaneo, E. Auffray, G. Auzinger, M. Bachtis,P. Baillon, A.H. Ball, D. Barney, A. Benaglia, J. Bendavid, L. Benhabib,J.F. Benitez, C. Bernet7,G. Bianchi, P. Bloch, A. Bocci, A. Bonato, O. Bondu,C. Botta,

H. Breuker, T. Camporesi, G. Cerminara, S. Colafranceschi36,M. D’Alfonso, D. d’Enterria, A. Dabrowski, A. David,F. De Guio, A. De Roeck, S. De Visscher, M. Dobson, M. Dordevic, N. Dupont-Sagorin,

A. Elliott-Peisert, J. Eugster,G. Franzoni, W. Funk, D. Gigi, K. Gill,D. Giordano, M. Girone, F. Glege, R. Guida, S. Gundacker, M. Guthoff,J. Hammer, M. Hansen, P. Harris,J. Hegeman, V. Innocente, P. Janot, K. Kousouris,K. Krajczar, P. Lecoq,C. Lourenço, N. Magini, L. Malgeri,M. Mannelli, J. Marrouche,

L. Masetti, F. Meijers, S. Mersi,E. Meschi, F. Moortgat, S. Morovic, M. Mulders, P. Musella, L. Orsini, L. Pape,E. Perez, L. Perrozzi,A. Petrilli, G. Petrucciani, A. Pfeiffer,M. Pierini, M. Pimiä, D. Piparo, M. Plagge, A. Racz,G. Rolandi37, M. Rovere,H. Sakulin, C. Schäfer, C. Schwick,A. Sharma, P. Siegrist, P. Silva,M. Simon, P. Sphicas38,D. Spiga, J. Steggemann,B. Stieger, M. Stoye, D. Treille, A. Tsirou, G.I. Veres18, J.R. Vlimant, N. Wardle, H.K. Wöhri, H. Wollny, W.D. Zeuner

CERN,EuropeanOrganizationforNuclearResearch,Geneva,Switzerland

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

F. Bachmair, L. Bäni, L. Bianchini, P. Bortignon, M.A. Buchmann,B. Casal, N. Chanon, A. Deisher,

G. Dissertori, M. Dittmar, M. Donegà, M. Dünser, P. Eller, C. Grab,D. Hits, W. Lustermann,B. Mangano, A.C. Marini,P. Martinez Ruiz del Arbol, D. Meister, N. Mohr,C. Nägeli39,F. Nessi-Tedaldi, F. Pandolfi, F. Pauss,M. Peruzzi, M. Quittnat,L. Rebane, M. Rossini, A. Starodumov40,M. Takahashi, K. Theofilatos, R. Wallny,H.A. Weber

InstituteforParticlePhysics,ETHZurich,Zurich,Switzerland

C. Amsler41,M.F. Canelli, V. Chiochia,A. De Cosa, A. Hinzmann, T. Hreus, B. Kilminster, C. Lange, B. Millan Mejias, J. Ngadiuba,P. Robmann, F.J. Ronga,S. Taroni, M. Verzetti, Y. Yang

UniversitätZürich,Zurich,Switzerland

M. Cardaci,K.H. Chen, C. Ferro, C.M. Kuo, W. Lin, Y.J. Lu,R. Volpe, S.S. Yu NationalCentralUniversity,Chung-Li,Taiwan

P. Chang,Y.H. Chang, Y.W. Chang,Y. Chao, K.F. Chen, P.H. Chen, C. Dietz,U. Grundler,W.-S. Hou,K.Y. Kao, Y.J. Lei, Y.F. Liu,R.-S. Lu, D. Majumder, E. Petrakou, Y.M. Tzeng,R. Wilken

NationalTaiwanUniversity(NTU),Taipei,Taiwan

B. Asavapibhop,N. Srimanobhas, N. Suwonjandee

ChulalongkornUniversity,Bangkok,Thailand

A. Adiguzel, M.N. Bakirci42,S. Cerci43, C. Dozen,I. Dumanoglu, E. Eskut, S. Girgis, G. Gokbulut, E. Gurpinar,I. Hos, E.E. Kangal, A. Kayis Topaksu,G. Onengut44, K. Ozdemir, S. Ozturk42, A. Polatoz, K. Sogut45, D. Sunar Cerci43,B. Tali43, H. Topakli42,M. Vergili

CukurovaUniversity,Adana,Turkey

I.V. Akin,B. Bilin, S. Bilmis, H. Gamsizkan, G. Karapinar46,K. Ocalan, S. Sekmen, U.E. Surat,M. Yalvac, M. Zeyrek

MiddleEastTechnicalUniversity,PhysicsDepartment,Ankara,Turkey E. Gülmez,B. Isildak47,M. Kaya48,O. Kaya49 BogaziciUniversity,Istanbul,Turkey

H. Bahtiyar50,E. Barlas, K. Cankocak, F.I. Vardarlı, M. Yücel IstanbulTechnicalUniversity,Istanbul,Turkey

L. Levchuk,P. Sorokin

NationalScientificCenter,KharkovInstituteofPhysicsandTechnology,Kharkov,Ukraine

J.J. Brooke,E. Clement, D. Cussans,H. Flacher, R. Frazier,J. Goldstein, M. Grimes, G.P. Heath, H.F. Heath, J. Jacob,L. Kreczko, C. Lucas, Z. Meng, D.M. Newbold51,S. Paramesvaran,A. Poll, S. Senkin, V.J. Smith, T. Williams

UniversityofBristol,Bristol,UnitedKingdom

K.W. Bell,A. Belyaev52,C. Brew, R.M. Brown, D.J.A. Cockerill, J.A. Coughlan, K. Harder,S. Harper, E. Olaiya,D. Petyt, C.H. Shepherd-Themistocleous, A. Thea,I.R. Tomalin, W.J. Womersley, S.D. Worm RutherfordAppletonLaboratory,Didcot,UnitedKingdom

M. Baber,R. Bainbridge, O. Buchmuller, D. Burton,D. Colling, N. Cripps,M. Cutajar, P. Dauncey, G. Davies, M. Della Negra,P. Dunne, W. Ferguson, J. Fulcher, D. Futyan,A. Gilbert, G. Hall,G. Iles, M. Jarvis,G. Karapostoli, M. Kenzie,R. Lane, R. Lucas51, L. Lyons, A.-M. Magnan, S. Malik,B. Mathias,