Contents lists available atScienceDirect
Physics
Letters
B
www.elsevier.com/locate/physletb
Search
for
resonant
W Z production
in
the
fully
leptonic
final
state
in
proton–proton
collisions
at
√
s
=
13 TeV with
the
ATLAS
detector
.TheATLAS Collaboration
a r t i c l e i n f o a b s t ra c t
Article history: Received5June2018
Receivedinrevisedform9October2018 Accepted11October2018
Availableonline18October2018 Editor:M.Doser
AsearchforaheavyresonancedecayingintoW Z inthefullyleptonicchannel(electronsandmuons)is performed. Itisbasedonproton–protoncollisiondata collectedbytheATLASexperimentattheLarge Hadron Collider ata centre-of-mass energy of13 TeV, corresponding to an integrated luminosity of 36.1 fb−1.NosignificantexcessisobservedovertheStandard Modelpredictionsandlimits areseton
theproductioncrosssectiontimesbranchingratioofaheavyvectorparticleproducedeitherinquark– antiquarkfusionorthroughvector-bosonfusion.Constraintsarealsoobtainedonthemassandcouplings ofasinglychargedHiggsboson,intheGeorgi–Machacekmodel,producedthroughvector-bosonfusion.
©2018TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/).FundedbySCOAP3.
1. Introduction
Searches for diboson resonances provide an essential test of theories of electroweaksymmetry breaking beyondthe Standard Model(BSM).VectorresonancesarepredictedinvariousBSM sce-narios,suchasinextendedgauge models [1,2],Little Higgs mod-els [3], Composite Higgs models and walking technicolor [4–6], unitarized Electroweak Chiral Lagrangian models [7], as well as intheories withextradimensions [8–10]. Inaddition,newscalar diboson resonances result from models with an extended Higgs sector [11,12].ThisLetterreportsonasearchfora W Z resonance inthe fullyleptonic decaychannel ν (=e or μ), produced either by quark–antiquark (qq) ¯ fusion or by vector-boson fusion (VBF).Theproton–protoncollisiondatawere collectedby the AT-LASdetector [13] attheLargeHadron Collider(LHC)ata centre-of-massenergy√s=13 TeV.
ParameterizedLagrangians [14–16] incorporatinga heavy vec-tor triplet (HVT) permit the interpretation of searches forvector resonancesinagenericway.Here,thesimplified phenomenologi-calLagrangianofRef. [15] isused.Thecouplingofthenewheavy vector resonance, V , tothe Higgsbosonandthe StandardModel (SM)gaugebosonsisparameterizedby gVcH andtothefermions via the combination (g2/gV)cF, where g is the SM SU(2)gauge coupling.Theparameter gV representsthetypical strengthofthe vector-bosoninteraction,whiletheparameters cH and cF are ex-pected to be of the order of unity in most models. The vector-boson scatteringprocess, pp →V j j →W Z j j, is only sensitiveto thegaugebosoncouplingand,inthiscase, thebenchmarkmodel
E-mail address:atlas.publications@cern.ch.
usedtointerprettheresultsassumesnocouplingoftheheavy vec-torresonancetofermions.
The Georgi–Machacekmodel(GM) [17,18] isusedasa bench-mark for a singly charged scalar resonance. The model extends the Higgs sector by including one real and one complex triplet, while preserving custodial symmetry, ensuring that the parame-ter ρ=M2W/(M2Zcos2θW)=1 at treelevel. Itis less experimen-tally constrained [19,20] than other models with higher isospin representations, such as Little Higgs models or Left–Right sym-metric models [21]. A parameter sinθH,representing the mixing ofthe vacuumexpectationvalues,determines thecontributionof thetripletstothemassesofthe W and Z bosons. Theten physi-calscalarstatesareorganizedintodifferentcustodialmultiplets:a fiveplet (H++5 , H5+,H05, H5−,H−−5 ) whichisfermiophobicbut cou-ples to W Z , atriplet,andtwosinglets,oneofwhichisidentified asthe 125 GeV SMHiggsboson.Assumingthat thetriplet states are heavierthan thefivepletscalars, H5 canonlybeproduced by vector-bosonfusionandthecrosssectionisproportionaltosin2θH. The singlychargedmembersofthisfivepletarethe objectofthe present search inthe VBF channel.For both modelsthe intrinsic widthofthe resonanceisbelow4%, whichislower than the ex-perimentalresolutioninnearlyalltheparameterspaceexploredin thepresentanalysis.
TheVBFprocess(pp→W Z j j) ischaracterizedbythepresence of two jetswith a large rapidity gapresulting fromquarks from whichavectorbosonhasbeenradiated.Theabsenceofthis topol-ogyisinterpretedas qq production, ¯ collectivelyreferredtohereas qq. ¯ Thespectrum ofthereconstructed invariant massofthe W Z resonance candidates isexamined forlocalized excessesover the expectedSMbackground.ResultsareprovidedfortheVBFand qq¯
https://doi.org/10.1016/j.physletb.2018.10.021
0370-2693/©2018TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).Fundedby SCOAP3.
categories separately, neglecting possible signal leakage between them.
EarlyresultsfromtheTevatron [22,23] haveput limitsonthe mass of a W boson of an extended gauge model [2] in the W Z channel between180GeVand690 GeV. The present analy-sis extends the search forresonant W Z production beyond that in Run 1 pp collision data at √s=8 TeV performed by the ATLAS [24] and CMS [25] collaborations. Each collaboration has combined results [26–28] from searches for heavy V V and V H resonances (V =W or Z ) based on Run 1 data and on partial Run2 dataat√s=13 TeV in thefullyhadronic(qqqq), semilep-tonic(νqq,qq, ννqq), andfullyleptonic(,ν,νν)final states.Morerecentresults from V V and V H resonance searches with data at √s=13 TeV have been reported in Refs. [29–38]. Thevariousdecaychannelsgenerallydifferinsensitivityin differ-ent massregions. The fully leptonic channel, in spite ofa lower branching ratio, is expected to be particularly sensitive to low-massresonancesasithaslowerbackgrounds.Arecentsearch [39] by the CMS Collaboration for a charged Higgs boson produced by vector-boson fusion and decaying into W Z in the fully lep-tonicmode,using15.2 fb−1 ofdatacollectedat√s=13 TeV,has yieldedlimitson the couplingparameter of the GMmodel,as a function of mass. Limits on the GM model have also been set, basedon analyses ofsame-charge W W production by CMS [40] andopposite-charge W W production byATLAS [41],usingdataat
√
s=13 TeV withanintegratedluminosityof36.1 fb−1. 2. ATLASdetector
TheATLAS detectorattheLHChasacylindricalgeometrywith anear 4π coverage in solidangle.1 Theinner detector(ID), con-sistingof silicon pixel,silicon microstrip and transitionradiation detectors,is surroundedby a thinsuperconducting solenoid pro-vidinga2 Taxialmagneticfield.Itallowsprecisereconstructionof tracksfromchargedparticles andmeasurementoftheirmomenta up to a pseudorapidity of |η|=2.5. High-granularity lead/liquid-argon (LAr) sampling electromagnetic and steel/scintillator-tile hadron calorimeters, at larger radius, provide energy measure-ments in thecentral pseudorapidity range|η|<1.7. In the end-cap and forward regions, LAr calorimeters for both the EM and hadronicenergy measurements extendthe region ofangular ac-ceptance up to |η|=4.9. Outside the calorimeters, the muon spectrometer incorporates multiple layers of trigger andtracking chambersinamagnetic field producedby asystemof supercon-ductingtoroidmagnets,enablinganindependentprecise measure-ment of muon track momenta for |η|<2.7. The ATLAS trigger systemconsistsofahardware-based level-1triggerfollowedby a software-basedhigh-leveltrigger [42].
3. DataandMonteCarlosamples
Thedatausedinthisanalysiswerecollected during 2015and 2016withtheATLASdetectorinpp collisions atacentre-of-mass energy of 13 TeV at the LHC. The minimum bunch crossing in-tervalis25 ns,withameannumberof23additionalinteractions perbunchcrossing.Theeventsarerequiredtohavepassed combi-nationsofsingle-electronorsingle-muon triggers.The transverse
1 ATLASusesaright-handedcoordinatesystemwithitsoriginatthe nominal interactionpoint(IP)inthecentreofthedetectorandthe z-axis alongthebeam pipe.The x-axis pointsfromtheIPtothecentreoftheLHCring,andthe y-axis pointsupwards.Cylindricalcoordinates(r,φ)areusedinthetransverseplane,φ beingtheazimuthalanglearoundthe z-axis. Thepseudorapidityisdefinedinterms ofthepolarangleθas η= −ln tan(θ/2).Angulardistanceismeasuredinunitsof R ≡(η)2+ (φ)2.
momentum thresholdof the leptons in2015 is 24GeVfor elec-tronsand 20GeV formuons satisfyinga loose isolation require-mentbasedonlyonIDtrackinformation.Duetothehigher instan-taneousluminosityin2016thetriggerthresholdwasincreasedto 26GeVforbothelectronsandmuonsandtighterisolation require-ments were applied. Additional electron and muon triggers that donotincludeanyisolationrequirementswithtransverse momen-tumthresholdsof pT =60GeVand50GeV,andasingle-electron triggerrequiringpT >120GeVwithlessrestrictiveelectron iden-tificationcriteriaareusedtoincreasetheselectionefficiencywhich reachescloseto 100%.Events areacceptedonlyifquality criteria for detectorand data conditions are satisfied. Withthese condi-tions,theavailabledatasetscorrespondtoanintegratedluminosity of36.1 fb−1.
Samples of simulated data were produced by Monte Carlo (MC) generators with the detector response obtained from the Geant4toolkit [43,44].Forsomesamples,thecalorimeterresponse is obtained from a fast parameterized simulation [45], instead of Geant4. Additionalsimulated inelastic pp collisions, generated with Pythia 8.186 [46] withthe A2setof tunedparameters [47] and the MSTW2008LO [48] parton distribution function (PDF), were overlaid inordertomodel boththe in- andout-of-time ef-fectsfromadditional pp collisions (pile-up)inthesameand neigh-bouring bunch crossings. The mean numberof pile-up events in theMCsampleswassettoreflecttheconditionsinthedata.
For the HVT interpretation, W→W Z samples were gener-ated. Twobenchmark models, provided in Ref. [15], are used. In Model A, weakly coupledvector resonances arise froman exten-sion of the SM gauge group [49] with an additional SU(2) sym-metry group and the branching fractions to fermions and gauge bosons are comparable. In Model B, the heavy vector triplet is producedina stronglycoupledscenario,asinaComposite Higgs model [50] andfermionic couplingsare suppressed.The parame-ter gV was setto 1 forModelA andto3 forModel B.Forboth models,theparameter cF isassumedtobethesameforall types of fermions. Simulated signal samples for the HVT benchmark ModelA weregeneratedformassesofvector resonances ranging from250 GeV to3 TeV with MadGraph_aMC@NLO 2.2.2 [51], us-ing the model file provided by the authorsin Ref. [52] with the NNPDF23LO [53] PDFset.Theyarehadronized with Pythia 8.186. ForinterpretationintermsofModelB,theModelAcrosssections aresimplyscaled.Thisisjustifiedsincethewidthremainswell be-low theexperimentalresolutionandtheangulardistributionsare thesameforbothmodels.
Forthe VBFproduction channel,HVTsamples were generated with gV=1 formassesrangingfrom250 GeV to2 TeV.The cou-pling parameter cH was set to 1 and all other couplings of the heavytriplet,including cF,weresetto0inordertomaximizethe VBF contribution.A dijetinvariant massof atleast150 GeV was requiredduringeventgeneration.
For the GMsignal samples, pp →H±5 j j →W±Z j j were pro-ducedwith MadGraph_aMC@NLO 2.2.2forthemassrange200to 900GeVinthe H5-planedefinedin [54],compatiblewithpresent limits [20,55], using GMCALC [56] and with sinθH =0.5. They wereproducedatleadingorder,butnormalizedtonext-to-leading orderaccordingto Ref. [11],wherethecrosssectionsandwidths, which scale assin2θH,are also given. Forthese samples,a min-imum pT of 15 GeV (10 GeV)forthe jets(leptons) was required during event generation and the pseudorapidity must be in the range|η|<5 forjetsand|η|<2.7 forleptons.
Thebackgroundsources inthisanalysisincludeprocesseswith twoormoreelectroweakgaugebosons,namely V V and V V V as well asprocesseswithtopquarks,such as t¯t, t¯t V , single topand t Z , andprocesseswithgaugebosonsproducedinassociationwith jetsorphotons( Z+j and Zγ).MCsimulationisusedtoestimate
the contribution from background processes with three or more promptleptonswhiledata-driventechniquesareusedforthecase of background processes withat least one misidentified or non-promptlepton.Simulatedeventsareusedforcrosschecksandto assessthesystematicuncertaintiesinthesebackgrounds.
ThedominantW Z SM backgroundprocessoforder(α2α2 s) in-volving colour-exchange diagrams, here referred to asQCD W Z , was modelled using Sherpa 2.2.2 [57] at next-to-leading order (NLO),andincludeshard-scattering,partonshower, hadronization andthe underlyingevents.Up tothree additionalpartons gener-atedattreelevelweremergedwiththepartonshower.Inorderto estimatean uncertaintyduetothepartonshowermodelling, two alternative W Z samples wereproducedusing Powheg-Boxv2 [58] interfaced with Pythia 8.186 and Herwig++ [59], respectively. A sampleofthepurelyelectroweakprocess W Z j j → ν j j (la-belled W Z j j) witha matrix-element b-quark veto(at zero order in αs) was generatedseparately with Sherpa 2.2.2. Contributions from W Z jb → ν bj (labelled W Z bj) are included in the t Z sample described below. To estimate an uncertainty due to the partonshowermodellinganalternative Madgraph+Pythia 8 sam-plewasproduced.This Madgraph sampleincludes b-quarks inthe initial state and was split to provide a sample without (with) a b-quark in thefinal stateto modelthe W Z j j (t Z+W Z bj) back-ground.
Samplesof qq¯→Z Z→4 or qq¯→Z Z→ νν were gener-ated by Powheg-Boxv2 at NLO, interfaced to Pythia 8.186 and normalizedtoNNLOby K -factors evaluatedinRef. [60].The gg→ Z Z and tribosons weregenerated with Sherpa 2.1.1.The tt V and ¯ t Z processes weregeneratedatLOusing Madgraph_aMC@NLO, in-terfacedwith Pythia 8.186 (t¯t V ) and Pythia 6.428(t Z ). The tt V¯ sampleswerenormalizedtoNLOpredictions [11].
Finally samplesofSMbackgrounds withatleastone misiden-tified or non-prompt lepton, including Zγ, Wγ, Drell–Yan Z→
, W → ν as well as top-pair and single-top were gener-atedtoassistinthefake/non-promptleptonbackgroundestimate. Events with Zγ and Wγ in the final state were generated with Sherpa2.1.1.Drell–Yan Z→ , W→ ν aswell astop-pairand single-topproductionchannelsweregenerated with Powheg-Box v2andhadronizedwith Pythia.Toavoiddoublecountingthe Zγ events,Z events producedbytheDrell–Yanprocesswithaphoton from final-state radiation with pT>10 GeV were removed. The partonshower forprocesses withtop quarks was modelled with Pythia 6.428. Madgraph_aMC@NLO and Pythia 8.186 were used forbackgroundprocessesinvolvingapairoftopquarks accompa-nied by a W boson orby a pair ofcharged leptons. The Z and single-top cross sections were normalized to NNLO by K -factors evaluatedinRef. [60,61].
SM backgrounds with Higgs bosons (H,tt H¯ , V H ) contribute less than 0.1% of the total background because of the low cross section andthe requirementofawell reconstructed Z boson de-cayingleptonically.Thesebackgroundsareneglected.
4. Reconstructedobjects
Events are required to have at leastone primary vertex with at least two associated tracks, each with transverse momentum pT>0.4 GeV. If there is more than one vertexreconstructed in the event, the one with the largest trackp2T ischosen asthe hard-scatter primary vertex andis subsequentlyused for the re-constructionofelectrons,muons, jetsandmissingtransverse mo-mentum.
Electroncandidates are reconstructedfrom energydeposits in the EM calorimeter which are matched to a well-reconstructed ID track originating fromthe primary vertex. The electron iden-tification is based on a likelihood evaluated from a multivariate
discriminant.Theyarecategorizedassatisfyingthe medium or the tight reconstruction quality requirements, asdefined inRef. [62]. Onlyelectronswithtransverseenergy ET>25 GeV inthe pseudo-rapidityrange|η|<2.47 areconsideredinthisanalysis.The candi-dateelectronsarerequiredtopassanisolationcondition:anupper valueofthescalarsumofthetransversemomentumofthetracks with pT>0.4 GeV in a cone of size R =min(0.2,10 GeV/ET) around the electron,excluding the trackof the electron itself, is chosen suchthattheefficiencyisconstantat99%forelectrons in Z→ee events. For tight electrons, anisolationrequirementis im-posed,basedoncalorimeteraswellastrackvariables,whichvaries asafunctionoftransverseenergyandyieldsanefficiencybetween 95% and 99% forelectrons with pT in the range25–60 GeV. For a pair of electrons sharing the same ID-track, the electron with highercluster ETiskept.
Muons are reconstructed by combining tracks from the inner detector with tracks from the muon spectrometer. They are re-quiredtosatisfy medium or tight quality requirements,asdefined in Ref. [63]. Only muons with pT>25 GeV and |η|<2.7 are considered in this analysis. Isolation requirements are also ap-pliedtoall muons,basedontheratio pvarcone
T /p μ
T,where pvarconeT is the scalar sumof the transverse momenta of the tracks with pT>1 GeV in acone ofsize R =min(10 GeV/pμT,0.3) around themuon,excludingthemuontrackitself.Thisisolationgives99% efficiency,independentlyof ηor pμT,in Z→μμsamples.
Electron and muon candidates are required to originate from theprimaryvertex. Thus,thesignificanceofthetrack’stransverse impact parameter calculated relative to the beam line, |d0/σd0|, mustbelessthanthreeformuonsandlessthanfiveforelectrons, andthelongitudinalimpactparameter, z0 (thedifferencebetween the value of z of the point on the track at which d0 is defined andthelongitudinalpositionoftheprimaryvertex),isrequiredto satisfy|z0·sin(θ )|<0.5 mm.
Jetsarereconstructedfromclustersofenergydepositioninthe calorimeter [64] usingtheanti-kt algorithm [65] witharadius pa-rameter R =0.4. Events with jetsarising fromdetector noise or other non-collisionsourcesarediscarded [66].Thissearch consid-ers jets with pT>30 GeV in the range |η|<4.5. Furthermore, to mitigate the pile-up contamination, a jet vertex tagger [67], based on information about tracks associated with the primary vertex and pile-up vertices, is applied to jets with pT<60 GeV and |η|< 2.4. The selected working point provides at least92% efficiency. The energy ofeach jet is calibrated and corrected for detector effects using a combination of simulated events and in situmethodsin13 TeV data [68].
As lepton and jet candidates can be reconstructed from the same detector information,a procedure to resolve overlap ambi-guities is applied. If an electron anda muon share the sameID track,themuonisselected.Reconstructedjetswhichoverlapwith electronsormuonsinaconeofsizeR =0.2 areremoved.
Jetscontaining b-hadrons areidentifiedas b-jets by theMV2c10 b-tagging algorithm [69], which uses information such as track impact-parameter significances and positions of explicitly recon-structed secondarydecayvertices.Aworkingpointcorresponding to85% b-tagging efficiencyonasampleof tt events ¯ ischosen [70], withalight-flavourjetrejectionfactorofabout34anda c-jet re-jectionofabout3.Correctionfactorsareappliedtothesimulated event samples to compensate for differences between data and simulation in the b-tagging efficiencyfor b-jets, c-jets and light-flavourjets.
The missing transverse momentum, pmiss
T , and its magnitude EmissT , are calculated from the imbalance in the sum of visible transverse momenta of reconstructed physics objects: electrons, muonsandjets,aswellasa“soft”termreconstructedfromtracks
Fig. 1. Thesignalselectionacceptancetimesefficiency(A×),definedastheratioofthenumberofMCsignaleventsintheVBFcategorytothenumberofgeneratedsignal events,ispresentedasafunctionoftheresonancemass.Fig.1(a)correspondstotheGMModel H±5 whileFig.1(b)correspondstotheHVTmodels.TheA×isshownfor eachdecaychannelandthesumofallleptonflavourcombinations(inclusive).Theerrorbarsshownineachfigurerepresentthetotalstatisticalandsystematicuncertainties.
compatiblewiththeprimaryvertexandnotassociatedwithanyof thoseobjects [71,72].
5. Eventselection
Preselectioncriteriaare first applied to all theeventsamples. The presence of three prompt leptons is required, two of which willbeassociatedwiththe Z boson, andarerequiredtosatisfythe medium quality requirement(Section4).The Z boson candidateis reconstructedfromthetwo leptons ofsameflavour andopposite charge,whose invariant massisclosest to theon-shell mass mZ, andintherange|m−mZ|<20 GeV.Thethirdlepton,associated withthe W boson decay, is required to satisfy the tight quality criteriato enhance the background rejection. To ensure that the triggerefficiencyiswelldetermined,atleastoneofthecandidate leptonsisrequiredtohavepT>27 GeV.
To suppress background processes with at least four prompt leptons, events with a fourth lepton candidate satisfying looser selectioncriteriaarerejected.Forthislooserselection,the require-mentontheminimum pT oftheleptonsisloweredto pT>7 GeV and medium identification requirementsareusedforboththe elec-tronsandmuons.
Sincethereisaneutrinointhesignalevents,EmissT >25 GeV is alsorequired.Thethirdleptonandthemissingtransverse momen-tumareassumedtoresultfromthe W boson decay.The longitu-dinalmomentum pνz oftheneutrinoiscalculatedbyrequiringthat theinvariantmassofthelepton–neutrinosystembe equaltothe W mass. Thesolutionresultsinaquadraticequation whichleads totwopossiblesolutions.Iftheyarereal,theonewiththesmaller
|pνz| is chosen since it was found to provide a better agreement withthe truth. Otherwise, the real part is chosen. The invariant mass, mW Z,ofthe W Z resonance candidateisthenreconstructed usingthechosen solutionforpνz alongwiththefour-momentaof thethreechargedleptons.
Theselectedeventsarethenseparatedintotwocategories tar-getingdifferentproductionmechanisms:VBFand qq. ¯ TheVBF cat-egory contains events withtwo or more jets with pT>30 GeV whichfailthe b-tagging requirementsdescribed inSection 4.The dijetpair defined by the two highest-pT jets in the event must alsohave large η separation (|ηj j|>3.5) and an invariant mj j above500 GeV.If morethantwo jetsare foundin anevent, the twohighest-pTjetsareconsidered.Byimposinga b-jet veto, back-groundscontainingoneormoretopquarks,including tt, t¯ ¯t+W/Z , and t Z are suppressed.
Thenetacceptancetimesefficiency(A×)oftheselection, rel-ativeto signal events generated for H5± and HVT models in the
Fig. 2. Thesignalselectionacceptancetimesefficiency(A×),definedastheratio ofthenumberofMCsignaleventsinthe qq category ¯ tothenumberofgenerated signalevents,asafunctionoftheHVTresonancemass.Theerrorbarsrepresentthe totalstatisticalandsystematicuncertainties.
VBFcategory isshowninFig.1.ThegenerationoftheGMModel H5±eventshadthefollowingrequirements: pT(jets)>15 GeV,pT (leptons) > 10 GeV, |η|(jets) <5 and |η|(leptons) <2.7. Decays of W bosons into alllepton flavours,andof Z bosons into e+e− and μ+μ−, were simulated. The Z →τ+τ− decays give a neg-ligible contributionandwere not included inthe simulation,but theA× shownwasscaledtoincludealldecays.FortheHVTVBF samples, mj j>150 GeV wasrequiredatgeneratorlevel.Decaysof W and Z bosons into all flavours of leptons were included. For HVTand H±5 theA× fallsinthe range2–8%and3–12% respec-tivelyforresonancemassesrangingbetween200and900 GeV,the differencebeingdue,withapproximatelyequalimportance,tothe generatorlevelselectionandtothedifferentangulardistributions ofthefinalproducts.
The remaining events are assigned to the qq category ¯ signal region. Forthiscategory, the W and Z bosons froma resonance producedinthes-channelwith mW Z largerthan250 GeV are ex-pectedto havetransversemomentacloseto50% ofitsmass.The requirements pW
T /mW Z >0.35 and pTZ/mW Z>0.35 enhance the sensitivitytothesignal.The overallselectionefficiencyrelativeto generated eventincreasesfrom about15% to 25% forresonances masses ranging from 500 GeV to 3 TeV as illustrated in Fig. 2. Decays of W and Z bosons into all flavours of leptons are in-cludedateventgeneration.TheA×valuesdecreaseforresonance massesaboveapproximately2 TeV duetothecollinearityof elec-tronsfromthe Z→ee decays whichspoilstheisolation.
Fig. 3. Observedandexpecteddistributionsofthe W Z invariant massin(a)the qq validation ¯ regionand(b)theVBFvalidationregion.Thepointscorrespondtothedata andthehistogramstotheexpectationsforthedifferentSMprocesses.Theuncertaintyinthetotalbackgroundprediction,shownasbands,combinesstatistical,theoryand systematiccontributions.Thebinsizeswerechosentoreflecttheresolutionofareconstructedsignal,andthewidthoftheprevioustolastbinisusedtoscalethebin contents.Thelastbincontainstheoverflow.
6. Backgroundestimation
The dominant background in the resonance search is the SM productionof W Z . Itsnormalizationandshapeareestimatedfrom MCandvalidatedindedicatedvalidationregionsbycomparingthe dataandMCdistributions.Eventsinthevalidationregionsare se-lectedinexactlythesamewayasthoseintheircorresponding sig-nalcategoriesexceptforthefollowingrequirements.TheVBF W Z validationregion isdefinedby invertingthe requirementsonthe dijetvariables:100<mj j<500 GeV and|ηj j|<3.5.The W Z qq¯ validation region requires the events to have pZT/mW Z<0.35 or pW
T /mW Z <0.35. These validation regions are dominated by the W Z contribution, with apurity higherthan 80%. Forthe bench-markmodelswithparameters givenin Section3, thesignal con-taminationinthe qq (VBF) ¯ validationregionisbelow5%(1%).The reconstructed mW Z mass in the validation regions is shown in Fig. 3, where good agreement of data withthe background pre-dictionisobserved.
Eventsfrom Z+jets, Zγ, Wγ, tt, ¯ singletopor W W where jets or photons were misidentified as leptons (here called fake/non-prompt leptons), canalso satisfy theselection criteria. The distri-bution shapesandnumberof fake/non-prompt lepton eventsare estimated for both the qq and ¯ VBF categories by a data-driven method using a global matrix which exploits differences in ob-ject characteristicsbetweenreal andfake/non-prompt leptons on astatisticalbasis.Detailsofthemethod,herereferred toas “Ma-trixMethod”,canbefoundinRef. [73].
Otherbackgroundsinclude tt V , ¯ Z Z , t Z , W Zbj and tripleboson production. They are estimated by Monte Carlo simulation (Sec-tion3).The t Z , W Z bj and V V V backgrounds areaddedasasingle contribution,herecalled t Z+V V V .
7. Systematicuncertainties
Systematicuncertainties resultfrom thetheoretical modelling ofbackgroundsandfromobjectandeventreconstruction.
The uncertainty in the normalization of the Sherpa samples of SM W Z background is evaluated by taking into account the variations obtainedwithdifferentPDF sets [74].The nominalset NNPDF30nloas0118 is compared with other samples generated withtheCT14nnloandMMHT2014nlo68clPDFsetsandthe uncer-taintyisevaluated fromthemaximumdifferences.It isestimated
to be below 6% in all mass bins for both the VBF and qq cate-¯ gories.Theuncertaintyassociatedwiththechoiceof renormaliza-tionandfactorizationscales, μRand μF,istakenasthemaximum downwardandupwardvariationwhenthescalesarevaried inde-pendentlybyfactorsof1/2and2.Whiletheseuncertaintiescanin principleaffecttheshapeofthe mW Z distribution,inpracticethe shapedifferencesdonothaveastrongimpactonthesensitivityof thesearch.Theuncertaintiesarethereforetreatedasnormalization uncertainties,takentobe20%and40%respectively.Shape system-aticuncertainties associatedwithshoweringandhadronizationof theQCD W Z are evaluatedbycomparingthe Powheg-Boxv2 sam-plesinterfacedwith Pythia 8.186and Herwig.Fortheelectroweak W Z process the Sherpa 2.2.2and Madgraph+Pythia 8predictions are compared. Thisuncertaintyband ranges from10% to30% for bothcategories.
The uncertainties assigned to the cross sections of the other backgroundsources consistofacontributionfromPDF uncertain-ties and fromQCD scale uncertainties. Theyare estimatedto be 10%for Z Z , 13%for tt V , 20%for V V V and 15%for t Z .
The theoretical uncertainties in the cross section and accep-tance of the simulated signal samples are evaluated in a similar waytothebackground.ThePDFerrorsaretakenfromtheNNPDF LO PDF error set, andthe NNPDF set is alsocompared with the CTEQ6L1andMSTW2008lo68clsets.Thedifferentpredictionsfrom these PDF sets are takenas an extra contribution to the overall uncertainty. For both the qq and ¯ VBF categories, the uncertain-tiesare typicallybelow5%.This procedurewas followedforeach mass point and a generator-level event selection was chosen to closely mimic the one used in the reconstruction-level analysis. ScaleandPDFuncertaintiesarenotcorrelatedbetweensignaland background.
Anuncertaintyduetothereconstructionefficiency,momentum scalesandresolutionofelectronsandmuonsisevaluatedby vary-ing correction factors applied to the MC samples [63,75] within appropriatelimits.
The jet energy scale and resolution uncertainties [66] are also taken into account as they affect the shape and normal-ization of the background distributions. The uncertainty due to b-tagging [76] isalsoincluded.
Missing transverse momentum is calculated using the prese-lectedleptons,jetsandotherreconstructedobjects.The uncertain-tiesinthereconstructionofthoseobjectsarethenusedtoevaluate
Table 1
Impactofthedominantsourcesofrelativeuncertaintiesonthe95%CLupperlimitsofthesignal-strength parameter(μ)forahypotheticalHVTsignalofmass m(W)=800 GeV inthe qq category ¯ andaGMsignal ofmass m(H±5)=450 GeV intheVBFcategory.Theeffectofthestatisticaluncertaintyonthesignaland backgroundsamplesisalsoshown.Sourcesofsystematicuncertaintywithanimpactoflessthan2%inboth categoriesarenotshown.
Source μ/μ[%]
qq category¯ VBF category m(W)=800 GeV m(H±5)=450 GeV
W Z background modelling: scale, PDF 5 11
W Z background modelling: parton shower 10 6
MC statistical uncertainty 7 8
Electron identification 4 2
Muon identification 3 3
Jet uncertainty 1 8
Missing transverse momentum 2 1
Fake/non-prompt 1 5
Total systematic uncertainty 17 21
Statistical uncertainty 53 52
theuncertaintyin Emiss
T reconstruction.Those duetothe pT scale andresolutionofthesofttermarealsoconsidered [71,72].
Anuncertaintyinthepredictionofthefake/non-prompt back-groundisalsotakenintoaccountasitaffectstheshapeand nor-malizationof the background distributions. The total uncertainty isabout20% (27%) for the qq (VBF) ¯ category. It is slightlylarger fortheVBF category becauseofthe higherstatisticaluncertainty derivedfromtheMatrixMethod(Section6).
The uncertaintyin the integrated luminosity is 2.1%. It is de-rived, following a methodology similar to the one detailed in Ref. [77], from a calibration of the luminosity scale using x– y beam-separationscansperformedinAugust2015andMay2016. 8. Results
The W Z invariant massdistribution, mW Z,obtainedasthesum ofallfourlepton-flavorpermutations,isusedasthediscriminating variable,withbinwidthscomparabletotheexpectedresolutionof anarrowresonantsignal.Abinnedlikelihoodfunction,constructed fromthePoissonprobabilityofthesum,ineachbin,ofthe contri-butionsofthebackgroundandofahypotheticalsignalofstrength μ relative to the benchmark model,is used to set limitson the presenceofa signal.The fitisperformedinthesignal regionfor the qq and ¯ VBF categories separately. The systematic uncertain-tiesdescribedabove(Section7)enterasnuisanceparameterswith Gaussianorlog-normalpriordistributions,inconvolutionwiththe nominalbackgrounddistribution.
Theeffectsof systematicuncertainties are studiedfor hypoth-esizedsignals using the signal-strength parameter μ. The list of leading sources of uncertainty in the 95% confidence level (CL) upper limit on the μ value is given in Table 1 together with their relative importance (μ/μ). The values are quoted sepa-ratelyforahypotheticalHVTsignalofmass m(W)=800 GeV in the qq category ¯ andaGMsignalofmass m(H±5)=450 GeV inthe VBFcategory. Apart fromthestatisticaluncertainties in thedata, theuncertainty with thelargest impact on the sensitivityof the searchesisrelatedtothe W Z background modelling.
The numbers of background events are extracted through a background-onlyfitofthedataineachcategory. Background con-tributions frompromptleptons, including their shapes, aretaken fromMCsimulations.Inthecaseofnon-promptleptonsthe back-groundshapesare takenfrom theMatrix Method.In the fit,the normalisationofallbackgroundsare allowed tovarywithin their uncertainties. The post-fit background yields are summarized in Table2 forthe qq and ¯ VBF categories. The fit constrains the SM W Z background estimatetotheobserveddata,whichreducesthe
Table 2
Expectedandobservedyieldsinthe qq and ¯ VBFsignalregions.Yieldsand uncer-taintiesareevaluatedafterabackground-onlyfittothedatainthe qq or ¯ VBFsignal regionsafterapplyingallselectioncriteria.Theuncertaintyinthetotalbackground estimateissmallerthanthesuminquadratureoftheindividualbackground con-tributionsduetoanti-correlationsbetweentheestimatesofdifferentbackground sources.
qq signal region¯ VBF signal region
W Z 521±29 87±12 Fake/non-prompt 64±13 15±4 t¯t V 29±4 4.9±0.8 Z Z 18.9±2.0 4.4±1.0 t Z+V V V 14.1±2.9 8.1±1.8 Total background 647±25 120±11 Observed 650 114
total background uncertainty, pulling themodelling uncertainties bylessthanonestandarddeviationfromtheirpre-fitvalues.None ofthenuisanceparametersare significantlypulledorconstrained relativetotheirpre-fitvaluesinthebackground-onlyfit.
Fig.4showsthepost-fit mW Z distributionforthe qq and ¯ VBF categories. The largest difference betweenthe observeddata and the SMbackground predictionisin theVBF category.A local ex-cess of events at a resonance mass of around 450 GeV can be seen in Fig. 4(b). The local significances for signals of H±5 and ofaheavy vector Ware 2.9and3.1standarddeviations, respec-tively.TherespectiveglobalsignificancescalculatedusingtheLook Elsewheremethod asinRef. [78] andevaluated up toa mass of 900 GeV, are 1.6and 1.9standard deviations. Inthe qq category ¯ thelargestdifferencebetweentheobserveddataandtheSM back-groundpredictionislocatedaroundamassof700 GeV withalocal significanceof1.2standarddeviations.
Upper limits are set on the product of the production cross section of new resonances and their decay branching ratio into W Z . Exclusion intervalsarederived usingtheCLs method [79] in the asymptotic approximation [80]. For masses higher than 900 (700) GeV in qq (VBF) ¯ category, the small number of expected events makes the asymptotic approximation imprecise and the limits are calculated using pseudo-experiments. The limit set on thesignal strength μisthen translatedintoa limitonthesignal crosssection timesbranchingratio, σ×B(W→W Z),usingthe theoretical cross section and branching ratiofor the givensignal model.
Fig. 5 presents the observed and expected limits on σ ×
B(W→W Z) at 95% CL for the HVT model in the qq cate-¯ gory. Massesbelow 2260 GeV can be excluded forModel A and
Fig. 4. Observedandexpecteddistributionsofthe W Z invariant mass(a)inthe qq and ¯ (b)intheVBFcategoriesafterapplyingallselectioncriteria.Signalpredictionsare overlaid,normalizedtothepredictedcrosssections.Theuncertaintyinthetotalbackgroundprediction,shownasshadedbands,combinesstatistical,theoryandsystematic contributions.Thelowerpanelshowtheratiosoftheobserveddatatothebackgroundpredictions.
Fig. 5. Observedandexpected95%CLupperlimitson σ× B(W→W±Z)forthe qq production ¯ ofa W bosoninthe HVTmodelsasafunctionofitsmass.The theoreticalpredictionsforHVTModelsAwith gV=1 andBwith gV=3 arealso
shown.
2460 GeV forModelB.Forresonancemassesabove2 TeV the ex-clusionlimitsbecomeworse duetotheacceptancelossesathigh mass.FortheVBFprocess,thelimiton σ×B(W→W Z)isshown inFig.6.
Observed and expected exclusion limits at 95% CL on σ ×
B(H5±→W±Z) and on the mixing parameter sinθH of the GM ModelareshowninFig.7asafunctionof mH±
5.Theintrinsicwidth ofthescalarresonance,forsinθH=0.5,isnarrowerthanthe de-tectorresolutioninthemassregionexplored.The shadedregions showtheparameterspaceforwhichthe H±5 widthexceeds5%and 10%of mH±5.
9. Conclusion
A search is performed for resonant W Z production in fully leptonic final states (electrons and muons) using 36.1 fb−1 of
√
s=13 TeV pp data collected by the ATLAS experiment atthe LHCduringthe2015and2016runperiods.Twodifferent produc-tionmodesareconsideredusingquark–antiquarkannihilationand vector-bosonfusion.
The datainthe qq fusion ¯ category are found tobe consistent with Standard Model predictions. The results are used to derive
Fig. 6. Observedandexpected95%CLupperlimitson σ× B(W→W±Z)forthe VBFproduction ofa W bosonintheHVTModel,with parameter cF=0,asa
functionofitsmass.
upperlimitsat95%CLonthecrosssection timesbranchingratio ofthephenomenologicalHeavyVectorTripletbenchmarkModelA (ModelB)withcouplingconstant gV=1 (gV=3)asafunctionof theresonancemass,withnoevidenceofheavyresonance produc-tionformassesbelow2260(2460) GeV.
InthecaseoftheVBFproductionprocesses,limitsonthe pro-ductioncrosssectiontimesbranchingratioareobtainedasa func-tionofthemassofachargedmemberofaheavyvectortripletor of the fiveplet scalar inthe Georgi–Machacek model. The results showalocalexcessofeventsovertheStandardModelexpectations at a resonance mass of around 450 GeV. The local significances forsignalsof H5±andofaheavyvector Wbosonare2.9and3.1 standarddeviationsrespectively.Therespectiveglobalsignificances calculated considering the Look Elsewhereeffect are 1.6and 1.9 standarddeviationsrespectively.
Acknowledgements
We thank CERN forthe very successful operation ofthe LHC, as well asthe supportstaff fromour institutions withoutwhom ATLAScouldnotbeoperatedefficiently.
Fig. 7. Observedandexpected95%CLupperlimitson(a) σ× B(H±5→W±Z)and(b)theparametersinθHoftheGMModelasafunctionof mH±5.Theshadedregionshows
wherethetheoreticalintrinsicwidthoftheresonancewouldbelargerthan5%or10%ofthemass.
WeacknowledgethesupportofANPCyT,Argentina;YerPhI, Ar-menia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azer-baijan;SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI,Canada; CERN; CONICYT,Chile; CAS, MOSTandNSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic;DNRFandDNSRC,Denmark;IN2P3-CNRS,CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF, andMPG, Germany; GSRT, Greece;RGC,HongKong SAR,China;ISFandBenoziyo Center, Is-rael; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands;RCN, Norway;MNiSW andNCN, Poland;FCT, Portu-gal;MNE/IFA,Romania;MESofRussiaandNRCKI,Russian Feder-ation;JINR;MESTD,Serbia;MSSR,Slovakia;ARRSandMIZŠ, Slove-nia; DST/NRF, South Africa; MINECO, Spain;SRC and Wallenberg Foundation,Sweden;SERI,SNSF andCantonsofBernandGeneva, Switzerland;MOST,Taiwan; TAEK,Turkey;STFC,UnitedKingdom; DOE and NSF, United States of America. In addition, individ-ualgroups andmembershave received supportfrom BCKDF,the CanadaCouncil, CANARIE, CRC, ComputeCanada, FQRNT,andthe OntarioInnovationTrust, Canada;EPLANET, ERC,ERDF,FP7, Hori-zon 2020 andMarie Skłodowska-Curie Actions, European Union; Investissements d’Avenir Labex and Idex, ANR, Région Auvergne andFondationPartagerleSavoir,France;DFGandAvHFoundation, Germany;Herakleitos,ThalesandAristeiaprogrammesco-financed byEU-ESFandtheGreekNSRF;BSF,GIF andMinerva,Israel;BRF, Norway; CERCA Programme Generalitat de Catalunya, Generalitat Valenciana,Spain;theRoyalSocietyandLeverhulmeTrust,United Kingdom.
The crucialcomputing support fromall WLCG partners is ac-knowledged gratefully,in particularfromCERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Swe-den),CC-IN2P3(France),KIT/GridKA(Germany),INFN-CNAF(Italy), NL-T1(Netherlands),PIC(Spain),ASGC(Taiwan),RAL(UK)andBNL (USA),theTier-2facilitiesworldwideandlargenon-WLCGresource providers.Majorcontributorsofcomputingresources arelistedin Ref. [81].
References
[1]P.Langacker,R.W.Robinett,J.L.Rosner,Newheavygaugebosonsinppandpp collisions,Phys.Rev.D30(1984)1470.
[2]G.Altarelli,B.Mele,M.Ruiz-Altaba,Searchingfornewheavyvectorbosonsin
pp colliders,¯ Z.Phys.C45(1989)109.
[3]N.Arkani-Hamed,A.G.Cohen,E.Katz,A.E.Nelson,ThelittlestHiggs,J.High EnergyPhys.07(2002)034,arXiv:hep-ph/0206021 [hep-ph].
[4]K.Agashe,R.Contino,A.Pomarol,TheminimalcompositeHiggsmodel,Nucl. Phys.B719(2005)165,arXiv:hep-ph/0412089 [hep-ph].
[5]G.Giudice,C.Grojean,A.Pomarol,R.Rattazzi,Thestrongly-interacting light Higgs,J.HighEnergyPhys.06(2007)045,arXiv:hep-ph/0703164 [hep-ph].
[6]R.Foadi,M.T.Frandsen,T.A.Ryttov,F.Sannino,Minimalwalkingtechnicolor: setup forcolliderphysics, Phys.Rev.D76(2007)055005,arXiv:0706.1696 [hep-ph].
[7]R.L. Delgado, et al., Production of vector resonances at the LHC via WZ-scattering: aunitarized EChLanalysis, J.High Energy Phys. 11(2017) 098, arXiv:1707.04580 [hep-ph].
[8]L.Randall,R.Sundrum,Alargemasshierarchyfromasmallextradimension, Phys.Rev.Lett.83(1999)3370,arXiv:hep-ph/9905221.
[9]H.Davoudiasl,J.L.Hewett,T.G.Rizzo,BulkgaugefieldsintheRandall–Sundrum model,Phys.Lett.B473(2000)43,arXiv:hep-ph/9911262.
[10]C. Csaki,C.Grojean,H.Murayama, L.Pilo,J.Terning, Gaugetheoriesonan interval:unitaritywithoutaHiggs,Phys.Rev.D69(2004)055006,arXiv:hep -ph/0305237 [hep-ph].
[11]D.deFlorian,etal.,HandbookofLHCHiggscrosssections:4.Decipheringthe natureoftheHiggssector,arXiv:1610.07922 [hep-ph],2016.
[12]I.P.Ivanov,BuildingandtestingmodelswithextendedHiggssectors,Prog.Part. Nucl.Phys.95(2017)160,arXiv:1702.03776 [hep-ph].
[13]ATLASCollaboration,TheATLASexperimentattheCERNlargehadroncollider, J.Instrum.3(2008)S08003.
[14]J. deBlas, J.M. Lizana, M.Perez-Victoria, Combiningsearches ofZ’ and W’ bosons,J.HighEnergyPhys.01(2013)166,arXiv:1211.2229 [hep-ph].
[15]D.Pappadopulo,A.Thamm,R.Torre,A.Wulzer,Heavyvectortriplets:bridging theoryanddata,J.HighEnergyPhys.09(2014)060,arXiv:1402.4431 [hep-ph].
[16]D.Greco,D.Liu,HuntingcompositevectorresonancesattheLHC:naturalness facingdata,J.HighEnergyPhys.12(2014)126,arXiv:1410.2883 [hep-ph].
[17]H.Georgi,M.Machacek,DoublychargedHiggsbosons,Nucl.Phys.B262(1985) 463.
[18]M.S. Chanowitz,M.Golden,Higgsbosontripletswith M(W)=M(Z)cosθW,
Phys.Lett.B165(1985)105.
[19]S.Godfrey,K.Moats,ExploringHiggstripletmodelsviavectorbosonscattering attheLHC,Phys.Rev.D81(2010)075026,arXiv:1003.3033 [hep-ph].
[20]K.Hartling,K.Kumar,H.E.Logan,IndirectconstraintsontheGeorgi–Machacek model and implications for Higgsboson couplings,Phys. Rev.D91 (2015) 015013,arXiv:1410.5538 [hep-ph].
[21]R.N. Mohapatra, J.C. Pati,Left–right gauge symmetryand an“isoconjugate” modelofCPviolation,Phys.Rev.D11(1975)566.
[22]D0Collaboration,SearchforresonantWWandWZproductioninpp collisions¯
at?s=1.96TeV,Phys.Rev.Lett.107(2011)011801,arXiv:1011.6278 [hep-ex].
[23]CDFCollaboration,SearchfornewheavyparticlesdecayingtoZ Z→ ,j j
inpp collisions¯ at√s=1.96 TeV,Phys.Rev.D83(2011)112008,arXiv:1102. 4566 [hep-ex].
[24]ATLASCollaboration,Searchfor W Z resonancesinthefullyleptonicchannel using pp collisionsat√s=8TeV withtheATLASdetector,Phys.Lett.B737 (2014)223,arXiv:1406.4456 [hep-ex].
[25]CMSCollaboration,SearchfornewresonancesdecayingviaWZtoleptonsin proton–proton collisionsat√s= 8TeV, Phys.Lett.B740(2015)83,arXiv: 1407.3476 [hep-ex].
[26]ATLAS Collaboration,Combinationofsearches for W W , W Z ,and Z Z
reso-nancesinpp collisionsat√s=8TeV withtheATLASdetector,Phys.Lett.B 755(2016)285,arXiv:1512.05099 [hep-ex].
[27]ATLAS Collaboration,Searchesforheavydibosonresonancesinpp collisions
at√s=13TeV withtheATLASdetector,J.HighEnergyPhys.09(2016)173, arXiv:1606.04833 [hep-ex].
[28]CMSCollaboration,Combinationofsearchesforheavyresonancesdecayingto WW,WZ,ZZ,WH,and ZHbosonpairsinproton–protoncollisionsat √s=
8 and 13TeV,Phys.Lett.B774(2017)533,arXiv:1705.09171 [hep-ex].
[29]ATLASCollaboration,SearchforW W/W Z resonanceproductioninνqq final
statesinpp collisionsat √s=13TeVwiththeATLASdetector,arXiv:1710. 07235 [hep-ex],2017.
[30]ATLASCollaboration,SearchesforheavyZ Z andZ W resonancesintheqq
andννqq finalstatesinpp collisionsat√s=13 TeVwiththeATLASdetector, arXiv:1708.09638 [hep-ex],2017.
[31]ATLASCollaboration,Searchfordibosonresonanceswithboson-taggedjetsin
pp collisionsat√s=13 TeVwiththeATLASdetector,Phys.Lett.B777(2018) 91,arXiv:1708.04445 [hep-ex].
[32]ATLASCollaboration,SearchforheavyresonancesdecayingtoaW orZ boson
andaHiggsbosonintheqq¯()bb final¯ stateinpp collisionsat√s=13 TeV
withtheATLASdetector,Phys.Lett.B774(2017)494,arXiv:1707.06958 [hep -ex].
[33]ATLASCollaboration,SearchfornewresonancesdecayingtoaW or Z boson
andaHiggsbosoninthe+−bb,¯ νbb,¯ andνν¯bb channels¯ withpp collisions
at√s=13 TeVwiththeATLASdetector,Phys.Lett.B765(2017)32,arXiv: 1607.05621 [hep-ex].
[34]CMSCollaboration,Searchforheavyresonancesthatdecayintoavectorboson andaHiggsbosoninhadronicfinalstatesat√s=13 TeV,Eur.Phys.J.C77 (2017)636,arXiv:1707.01303 [hep-ex].
[35]CMSCollaboration,Searchfor massiveresonancesdecayinginto W W , W Z , Z Z ,qW ,andq Z withdijetfinalstatesat√s=13 TeV,Phys.Rev.D97(2018) 072006,arXiv:1708.05379 [hep-ex].
[36]CMSCollaboration,SearchforanewheavyresonancedecayingintoaZboson andaZorWbosonin22qfinalstatesat √s= 13TeV,arXiv:1803.10093 [hep-ex],2018.
[37]CMSCollaboration,SearchforaheavyresonancedecayingintoaZbosonand avectorbosonintheννqq finalstate,J. HighEnergy Phys.07(2018)075, arXiv:1803.03838 [hep-ex].
[38]CMSCollaboration,Searchforaheavyresonancedecayingtoapairofvector bosonsintheleptonplusmergedjetfinalstateat√s=13 TeV,J.HighEnergy Phys.05(2018)088,arXiv:1802.09407 [hep-ex].
[39]CMSCollaboration,SearchforchargedHiggsbosonsproducedviavectorboson fusion anddecayinginto apairof W andZ bosons usingpp collisionsat
√
s=13 TeV,Phys.Rev.Lett.119(2017)141802,arXiv:1705.02942 [hep-ex].
[40]CMSCollaboration,Observationofelectroweakproductionofsame-signW bo-sonpairsinthetwojetandtwosame-signleptonfinalstateinproton–proton collisionsat√s=13TeV,Phys.Rev.Lett.120(2018)081801,arXiv:1709.05822 [hep-ex].
[41]ATLASCollaboration,Searchforheavyresonancesdecayinginto W W inthe
eνμνfinalstateinpp collisionsat√s=13 TeVwiththeATLASdetector,Eur. Phys.J.C78(2018)24,arXiv:1710.01123 [hep-ex].
[42]ATLAS Collaboration,PerformanceoftheATLAS triggersystemin2015,Eur. Phys.J.C77(2017)317,arXiv:1611.09661 [hep-ex].
[43]S.Agostinelli,etal.,GEANT4:asimulationtoolkit,Nucl.Instrum.MethodsA 506(2003)250.
[44]ATLAS Collaboration,TheATLAS simulationinfrastructure,Eur.Phys.J. C70 (2010)823,arXiv:1005.4568 [hep-ex].
[45] ATLASCollaboration,ThesimulationprincipleandperformanceoftheATLAS fastcalorimetersimulationFastCaloSim,ATL-PHYS-PUB-2010-013,https://cds. cern.ch/record/1300517,2010.
[46]T.Sjostrand,S.Mrenna,P.Z.Skands,AbriefintroductiontoPYTHIA8.1,Comput. Phys.Commun.178(2008)852,arXiv:0710.3820 [hep-ph].
[47] ATLAS Collaboration, Summary of ATLAS Pythia 8 tunes, ATL-PHYS-PUB-2012-003,https://cds.cern.ch/record/1474107,2012.
[48]A.D.Martin,W.J.Stirling,R.S.Thorne,G.Watt,PartondistributionsfortheLHC, Eur.Phys.J.C63(2009)189,arXiv:0901.0002 [hep-ph].
[49]V.D.Barger,W.-Y.Keung,E.Ma,AgaugemodelwithlightW and Z bosons,
Phys.Rev.D22(1980)727.
[50]R.Contino,D.Marzocca,D.Pappadopulo,R.Rattazzi,Ontheeffectof reso-nancesincompositeHiggsphenomenology,J.HighEnergyPhys.10(2011)081, arXiv:1109.1570 [hep-ph].
[51]J.Alwall,etal.,Theautomatedcomputationoftree-levelandnext-to-leading orderdifferentialcrosssections,andtheirmatchingtopartonshower simula-tions,J.HighEnergyPhys.07(2014)079,arXiv:1405.0301 [hep-ph].
[52] D.Pappadopulo,A.Thamm,R.Torre,A.Wulzer,Heavyvectortriplets,http:// rtorre.web.cern.ch/rtorre/Riccardotorre/vector_triplet_t.html,2014.
[53]R.D.Ball,etal.,PartondistributionswithLHCdata,Nucl.Phys.B867(2013) 244,arXiv:1207.1303 [hep-ph].
[54]C.Degrande,K.Hartling,H.E.Logan,A.D.Peterson,M.Zaro,Automatic predic-tionsintheGeorgi–Machacekmodelatnext-to-leadingorderaccuracy,Phys. Rev.D93(2016)035004,arXiv:1512.01243 [hep-ph].
[55] M.Zaro,H.Logan,RecommendationsfortheinterpretationofLHCsearchesfor H0
5, H±5,and H±±5 invectorbosonfusionwithdecaystovectorbosonpairs,
https://cds.cern.ch/record/2002500,2015.
[56]K. Hartling, K. Kumar, H.E. Logan, GMCALC: a calculator for the Georgi– Machacekmodel,arXiv:1412.7387 [hep-ph],2014.
[57]T.Gleisberg,etal.,EventgenerationwithSHERPA1.1,J.HighEnergyPhys.02 (2009)007,arXiv:0811.4622 [hep-ph].
[58]S.Alioli,P.Nason,C.Oleari,E.Re,AgeneralframeworkforimplementingNLO calculationsinshowerMonteCarloprograms:thePOWHEGBOX,J.High En-ergyPhys.06(2010)043,arXiv:1002.2581 [hep-ph].
[59]M.Bahr,etal.,Herwig++physicsandmanual,Eur.Phys.J.C58(2008)639, arXiv:0803.0883 [hep-ph].
[60]M. Brucherseifer, F. Caola, K. Melnikov, On the NNLO QCD corrections to single-topproductionattheLHC,Phys.Lett.B736(2014)58,arXiv:1404.7116 [hep-ph].
[61]C.Anastasiou,L.J.Dixon,K.Melnikov,F.Petriello,HighprecisionQCDathadron colliders:electroweakgaugebosonrapiditydistributionsatNNLO,Phys.Rev.D 69(2004)094008,arXiv:hep-ph/0312266 [hep-ph].
[62] ATLASCollaboration,ElectronefficiencymeasurementswiththeATLAS detec-torusingthe2015LHCproton–protoncollisiondata,ATLAS-CONF-2016-024,
https://cds.cern.ch/record/2157687,2016.
[63]ATLASCollaboration,MuonreconstructionperformanceoftheATLASdetector inproton–protoncollisiondataat√s=13TeV,Eur.Phys.J.C76(2016)292, arXiv:1603.05598 [hep-ex].
[64] ATLASCollaboration,Jetenergyscaleanditssystematicuncertaintyinproton– protoncollisionsat√s=7TeV withATLAS2011data,ATLAS-CONF-2013-004,
https://cds.cern.ch/record/1509552,2013.
[65]M.Cacciari,G.P.Salam,G.Soyez,Theanti-ktjetclusteringalgorithm,J.High
EnergyPhys.04(2008)063,arXiv:0802.1189 [hep-ph].
[66]ATLAS Collaboration, Jet energy measurement with the ATLAS detector in proton–protoncollisionsat√s=7TeV,Eur.Phys.J.C73(2013)2304,arXiv: 1112.6426 [hep-ex].
[67]ATLASCollaboration,Performanceofpile-upmitigationtechniquesforjetsin
pp collisionsat√s=8 TeVusingtheATLASdetector,Eur.Phys.J.C76(2016) 581,arXiv:1510.03823 [hep-ex].
[68] ATLASCollaboration, Jetcalibrationand systematicuncertaintiesfor jets re-constructedintheATLASdetectorat √s=13TeV,ATL-PHYS-PUB-2015-015,
https://cds.cern.ch/record/2037613,2015.
[69]ATLASCollaboration,Performanceofb-jetidentificationintheATLAS experi-ment,J.Instrum.11(2016)P04008,arXiv:1512.01094 [hep-ex].
[70]ATLASCollaboration,Measurementsofb-jettaggingefficiencywiththeATLAS detectorusingt¯t eventsat√s=13 TeV,arXiv:1805.01845 [hep-ex],2018.
[71] ATLAS Collaboration, Performance ofmissing transverse momentum recon-structionwiththeATLASdetectorinthefirstproton–protoncollisionsat√s= 13TeV,ATL-PHYS-PUB-2015-027,https://cds.cern.ch/record/2037904,2015. [72] ATLAS Collaboration, Expected performance ofmissing transverse
momen-tumreconstruction for theATLAS detector at √s=13TeV, ATL-PHYS-PUB-2015-023,https://cds.cern.ch/record/2037700,2015.
[73]ATLASCollaboration,MeasurementsofW±Z productioncrosssectionsinpp
collisionsat √s=8TeV withthe ATLAS detectorand limits onanomalous gaugebosonself-couplings,Phys.Rev.D93(2016)092004,arXiv:1603.02151 [hep-ex].
[74]A.Buckley,etal.,LHAPDF6:partondensityaccessintheLHCprecisionera,Eur. Phys.J.C75(2015)132,arXiv:1412.7420 [hep-ph].
[75]ATLASCollaboration,ElectronefficiencymeasurementswiththeATLAS detec-torusing2012LHCproton–protoncollisiondata,Eur.Phys.J.C77(2017)195, arXiv:1612.01456 [hep-ex].
[76] ATLASCollaboration,OptimisationoftheATLASb-taggingperformanceforthe 2016 LHC run, ATL-PHYS-PUB-2016-012, https://cds.cern.ch/record/2160731, 2016.
[77]ATLASCollaboration,Luminositydeterminationinppcollisionsat√s=8 TeV usingtheATLASdetectorattheLHC,Eur.Phys.J.C76(2016)653,arXiv:1608. 03953 [hep-ex].
[78] ATLASCollaboration,ProcedurefortheLHCHiggsbosonsearchcombination insummer2011,ATL-PHYS-PUB-2011-011,https://cds.cern.ch/record/1375842, 2011.
[79]A.L.Read,Presentationofsearchresults:theCLstechnique,J.Phys.G28(2002)
2693.
[80]G.Cowan,K.Cranmer,E.Gross,O.Vitells,Asymptoticformulaefor likelihood-basedtests ofnewphysics, Eur.Phys. J.C71(2011)1554,arXiv:1007.1727 [physics.data-an];
G.Cowan,K.Cranmer,E.Gross,O.Vitells,Eur.Phys.J.C73(2012)2501, Erra-tum.
[81] ATLAS Collaboration, ATLAS computing acknowledgements2016–2017, ATL-GEN-PUB-2016-002,https://cds.cern.ch/record/2202407,2016.
TheATLASCollaboration
M. Aaboud34d, G. Aad99, B. Abbott124,O. Abdinov13,aw,B. Abeloos128,D.K. Abhayasinghe91,
S.H. Abidi165, O.S. AbouZeid143,N.L. Abraham153,H. Abramowicz159,H. Abreu158,Y. Abulaiti6,
B.S. Acharya64a,64b,o, S. Adachi161,L. Adamczyk81a,J. Adelman119,M. Adersberger112,A. Adiguzel12c,ah,
T. Adye141,A.A. Affolder143,Y. Afik158,C. Agheorghiesei27c,J.A. Aguilar-Saavedra136f,136a,
F. Ahmadov77,af,G. Aielli71a,71b,S. Akatsuka83, T.P.A. Åkesson94,E. Akilli52, A.V. Akimov108,
G.L. Alberghi23b,23a, J. Albert174,P. Albicocco49,M.J. Alconada Verzini86, S. Alderweireldt117,
M. Aleksa35, I.N. Aleksandrov77,C. Alexa27b,G. Alexander159, T. Alexopoulos10, M. Alhroob124,
B. Ali138, G. Alimonti66a,J. Alison36, S.P. Alkire145, C. Allaire128, B.M.M. Allbrooke153,B.W. Allen127,
P.P. Allport21, A. Aloisio67a,67b,A. Alonso39,F. Alonso86, C. Alpigiani145,A.A. Alshehri55,M.I. Alstaty99,
B. Alvarez Gonzalez35,D. Álvarez Piqueras172, M.G. Alviggi67a,67b, B.T. Amadio18,
Y. Amaral Coutinho78b, L. Ambroz131, C. Amelung26, D. Amidei103,S.P. Amor Dos Santos136a,136c,
S. Amoroso35, C.S. Amrouche52,C. Anastopoulos146,L.S. Ancu52, N. Andari21, T. Andeen11,
C.F. Anders59b, J.K. Anders20, K.J. Anderson36,A. Andreazza66a,66b,V. Andrei59a,S. Angelidakis37,
I. Angelozzi118,A. Angerami38,A.V. Anisenkov120b,120a, A. Annovi69a,C. Antel59a,M.T. Anthony146,
M. Antonelli49, D.J.A. Antrim169, F. Anulli70a,M. Aoki79,L. Aperio Bella35, G. Arabidze104, Y. Arai79,
J.P. Araque136a,V. Araujo Ferraz78b,R. Araujo Pereira78b,A.T.H. Arce47,R.E. Ardell91,F.A. Arduh86,
J-F. Arguin107, S. Argyropoulos75,A.J. Armbruster35,L.J. Armitage90, A Armstrong169, O. Arnaez165,
H. Arnold118, M. Arratia31,O. Arslan24, A. Artamonov109,aw,G. Artoni131,S. Artz97, S. Asai161,
N. Asbah44,A. Ashkenazi159,E.M. Asimakopoulou170,L. Asquith153, K. Assamagan29, R. Astalos28a,
R.J. Atkin32a,M. Atkinson171,N.B. Atlay148,K. Augsten138, G. Avolio35,R. Avramidou58a, B. Axen18,
M.K. Ayoub15a,G. Azuelos107,au,A.E. Baas59a, M.J. Baca21,H. Bachacou142, K. Bachas65a,65b,
M. Backes131,P. Bagnaia70a,70b, M. Bahmani82, H. Bahrasemani149, A.J. Bailey172, J.T. Baines141,
M. Bajic39,O.K. Baker181,P.J. Bakker118,D. Bakshi Gupta93,E.M. Baldin120b,120a, P. Balek178,F. Balli142,
W.K. Balunas133, E. Banas82, A. Bandyopadhyay24,S. Banerjee179,k, A.A.E. Bannoura180, L. Barak159,
W.M. Barbe37,E.L. Barberio102,D. Barberis53b,53a,M. Barbero99, T. Barillari113,M-S. Barisits35,
J. Barkeloo127, T. Barklow150,N. Barlow31,R. Barnea158,S.L. Barnes58c, B.M. Barnett141,R.M. Barnett18,
Z. Barnovska-Blenessy58a,A. Baroncelli72a, G. Barone26,A.J. Barr131,L. Barranco Navarro172,
F. Barreiro96,J. Barreiro Guimarães da Costa15a, R. Bartoldus150, A.E. Barton87,P. Bartos28a,
A. Basalaev134,A. Bassalat128,R.L. Bates55,S.J. Batista165,S. Batlamous34e,J.R. Batley31,M. Battaglia143,
M. Bauce70a,70b, F. Bauer142,K.T. Bauer169,H.S. Bawa150,m,J.B. Beacham122,M.D. Beattie87, T. Beau132,
P.H. Beauchemin168,P. Bechtle24, H.C. Beck51, H.P. Beck20,r, K. Becker50,M. Becker97,C. Becot121,
A. Beddall12d, A.J. Beddall12a,V.A. Bednyakov77,M. Bedognetti118, C.P. Bee152,T.A. Beermann35,
M. Begalli78b, M. Begel29,A. Behera152,J.K. Behr44,A.S. Bell92,G. Bella159,L. Bellagamba23b,
A. Bellerive33,M. Bellomo158, K. Belotskiy110, N.L. Belyaev110,O. Benary159,aw, D. Benchekroun34a,
M. Bender112, N. Benekos10,Y. Benhammou159, E. Benhar Noccioli181, J. Benitez75,D.P. Benjamin47,
M. Benoit52,J.R. Bensinger26,S. Bentvelsen118, L. Beresford131, M. Beretta49,D. Berge44,
E. Bergeaas Kuutmann170,N. Berger5, L.J. Bergsten26,J. Beringer18, S. Berlendis56, N.R. Bernard100,
G. Bernardi132, C. Bernius150,F.U. Bernlochner24, T. Berry91, P. Berta97,C. Bertella15a, G. Bertoli43a,43b,
I.A. Bertram87,G.J. Besjes39, O. Bessidskaia Bylund43a,43b,M. Bessner44,N. Besson142,A. Bethani98,
S. Bethke113, A. Betti24,A.J. Bevan90,J. Beyer113,R.M.B. Bianchi135, O. Biebel112,D. Biedermann19,
R. Bielski98, K. Bierwagen97, N.V. Biesuz69a,69b, M. Biglietti72a, T.R.V. Billoud107, M. Bindi51,
A. Bingul12d, C. Bini70a,70b,S. Biondi23b,23a, T. Bisanz51,J.P. Biswal159,C. Bittrich46, D.M. Bjergaard47,
J.E. Black150,K.M. Black25,R.E. Blair6,T. Blazek28a,I. Bloch44,C. Blocker26,A. Blue55,
U. Blumenschein90,Dr. Blunier144a, G.J. Bobbink118,V.S. Bobrovnikov120b,120a,S.S. Bocchetta94,
A. Bocci47,D. Boerner180,D. Bogavac112, A.G. Bogdanchikov120b,120a, C. Bohm43a, V. Boisvert91,
P. Bokan170,y,T. Bold81a, A.S. Boldyrev111, A.E. Bolz59b, M. Bomben132, M. Bona90,J.S. Bonilla127,
M. Boonekamp142,A. Borisov140, G. Borissov87, J. Bortfeldt35, D. Bortoletto131,
V. Bortolotto71a,61b,61c,71b,D. Boscherini23b,M. Bosman14,J.D. Bossio Sola30,J. Boudreau135,
E.V. Bouhova-Thacker87,D. Boumediene37, C. Bourdarios128,S.K. Boutle55,A. Boveia122,J. Boyd35,
I.R. Boyko77,A.J. Bozson91,J. Bracinik21,N. Brahimi99,A. Brandt8, G. Brandt180,O. Brandt59a,
A.J. Brennan102, L. Brenner44,R. Brenner170, S. Bressler178,B. Brickwedde97,D.L. Briglin21,D. Britton55,
D. Britzger59b, I. Brock24,R. Brock104,G. Brooijmans38,T. Brooks91, W.K. Brooks144b, E. Brost119,
J.H Broughton21,P.A. Bruckman de Renstrom82,D. Bruncko28b,A. Bruni23b,G. Bruni23b,L.S. Bruni118,
S. Bruno71a,71b,B.H. Brunt31,M. Bruschi23b,N. Bruscino135, P. Bryant36,L. Bryngemark44, T. Buanes17,
Q. Buat35,P. Buchholz148,A.G. Buckley55,I.A. Budagov77, F. Buehrer50,M.K. Bugge130,O. Bulekov110,
D. Bullock8, T.J. Burch119, S. Burdin88,C.D. Burgard118,A.M. Burger5, B. Burghgrave119, K. Burka82,
S. Burke141,I. Burmeister45,J.T.P. Burr131, D. Büscher50, V. Büscher97,E. Buschmann51, P. Bussey55,
J.M. Butler25,C.M. Buttar55, J.M. Butterworth92, P. Butti35,W. Buttinger35, A. Buzatu155,
A.R. Buzykaev120b,120a, G. Cabras23b,23a,S. Cabrera Urbán172, D. Caforio138, H. Cai171,V.M.M. Cairo2,
O. Cakir4a, N. Calace52, P. Calafiura18,A. Calandri99, G. Calderini132,P. Calfayan63, G. Callea40b,40a,
L.P. Caloba78b,S. Calvente Lopez96,D. Calvet37, S. Calvet37,T.P. Calvet152, M. Calvetti69a,69b,
R. Camacho Toro132, S. Camarda35,P. Camarri71a,71b,D. Cameron130, R. Caminal Armadans100,
C. Camincher35, S. Campana35,M. Campanelli92, A. Camplani66a,66b, A. Campoverde148,
V. Canale67a,67b,M. Cano Bret58c,J. Cantero125,T. Cao159, Y. Cao171,M.D.M. Capeans Garrido35,
I. Caprini27b,M. Caprini27b,M. Capua40b,40a,R.M. Carbone38,R. Cardarelli71a,F.C. Cardillo50, I. Carli139,
T. Carli35, G. Carlino67a, B.T. Carlson135,L. Carminati66a,66b,R.M.D. Carney43a,43b,S. Caron117,
E. Carquin144b,S. Carrá66a,66b, G.D. Carrillo-Montoya35,D. Casadei32b, M.P. Casado14,g, A.F. Casha165,
M. Casolino14,D.W. Casper169,R. Castelijn118, F.L. Castillo172, V. Castillo Gimenez172,
N.F. Castro136a,136e, A. Catinaccio35,J.R. Catmore130, A. Cattai35, J. Caudron24, V. Cavaliere29,
E. Cavallaro14,D. Cavalli66a,M. Cavalli-Sforza14,V. Cavasinni69a,69b,E. Celebi12b, F. Ceradini72a,72b,
L. Cerda Alberich172,A.S. Cerqueira78a, A. Cerri153, L. Cerrito71a,71b,F. Cerutti18,A. Cervelli23b,23a,
S.A. Cetin12b,A. Chafaq34a, D Chakraborty119, S.K. Chan57, W.S. Chan118, Y.L. Chan61a, P. Chang171,
J.D. Chapman31, D.G. Charlton21,C.C. Chau33,C.A. Chavez Barajas153, S. Che122,A. Chegwidden104,
S. Chekanov6,S.V. Chekulaev166a,G.A. Chelkov77,at, M.A. Chelstowska35, C. Chen58a,C.H. Chen76,
H. Chen29,J. Chen58a,J. Chen38, S. Chen133, S.J. Chen15c,X. Chen15b,as,Y. Chen80,Y-H. Chen44,
H.C. Cheng103,H.J. Cheng15d, A. Cheplakov77,E. Cheremushkina140, R. Cherkaoui El Moursli34e,
E. Cheu7,K. Cheung62,L. Chevalier142, V. Chiarella49,G. Chiarelli69a,G. Chiodini65a, A.S. Chisholm35,
A. Chitan27b, I. Chiu161, Y.H. Chiu174, M.V. Chizhov77,K. Choi63, A.R. Chomont128, S. Chouridou160,
Y.S. Chow118,V. Christodoulou92, M.C. Chu61a,J. Chudoba137,A.J. Chuinard101,J.J. Chwastowski82,
L. Chytka126, D. Cinca45,V. Cindro89, I.A. Cioar˘a24, A. Ciocio18, F. Cirotto67a,67b, Z.H. Citron178,
M. Citterio66a, A. Clark52, M.R. Clark38,P.J. Clark48, C. Clement43a,43b,Y. Coadou99,M. Cobal64a,64c,
A. Coccaro53b,53a, J. Cochran76,A.E.C. Coimbra178, L. Colasurdo117,B. Cole38, A.P. Colijn118,J. Collot56,
P. Conde Muiño136a,136b, E. Coniavitis50,S.H. Connell32b,I.A. Connelly98, S. Constantinescu27b,
F. Conventi67a,av,A.M. Cooper-Sarkar131, F. Cormier173, K.J.R. Cormier165,M. Corradi70a,70b,
E.E. Corrigan94, F. Corriveau101,ad,A. Cortes-Gonzalez35, M.J. Costa172,D. Costanzo146,G. Cottin31,
G. Cowan91, B.E. Cox98,J. Crane98, K. Cranmer121, S.J. Crawley55, R.A. Creager133,G. Cree33,
S. Crépé-Renaudin56,F. Crescioli132, M. Cristinziani24,V. Croft121, G. Crosetti40b,40a,A. Cueto96,
T. Cuhadar Donszelmann146,A.R. Cukierman150, M. Curatolo49,J. Cúth97,S. Czekierda82,
P. Czodrowski35, M.J. Da Cunha Sargedas De Sousa58b,136b,C. Da Via98,W. Dabrowski81a,T. Dado28a,y,
S. Dahbi34e,T. Dai103, F. Dallaire107,C. Dallapiccola100, M. Dam39,G. D’amen23b,23a,J.R. Dandoy133,
M.F. Daneri30, N.P. Dang179,k, N.D Dann98, M. Danninger173,V. Dao35,G. Darbo53b,S. Darmora8,
O. Dartsi5, A. Dattagupta127, T. Daubney44, S. D’Auria55, W. Davey24,C. David44,T. Davidek139,
D.R. Davis47, E. Dawe102,I. Dawson146, K. De8,R. De Asmundis67a, A. De Benedetti124,
S. De Castro23b,23a, S. De Cecco70a,70b, N. De Groot117,P. de Jong118, H. De la Torre104,F. De Lorenzi76,
A. De Maria51,t,D. De Pedis70a,A. De Salvo70a, U. De Sanctis71a,71b,A. De Santo153,
K. De Vasconcelos Corga99,J.B. De Vivie De Regie128, C. Debenedetti143,D.V. Dedovich77,
N. Dehghanian3, M. Del Gaudio40b,40a, J. Del Peso96, D. Delgove128, F. Deliot142,C.M. Delitzsch7,
M. Della Pietra67a,67b,D. Della Volpe52,A. Dell’Acqua35, L. Dell’Asta25, M. Delmastro5,C. Delporte128,
P.A. Delsart56, D.A. DeMarco165,S. Demers181, M. Demichev77, S.P. Denisov140,D. Denysiuk118,
L. D’Eramo132,D. Derendarz82,J.E. Derkaoui34d, F. Derue132, P. Dervan88, K. Desch24,C. Deterre44,
K. Dette165,M.R. Devesa30, P.O. Deviveiros35,A. Dewhurst141, S. Dhaliwal26, F.A. Di Bello52,
B. Di Micco72a,72b, R. Di Nardo35,K.F. Di Petrillo57,A. Di Simone50,R. Di Sipio165, D. Di Valentino33,
C. Diaconu99, M. Diamond165,F.A. Dias39, T. Dias Do Vale136a,M.A. Diaz144a,J. Dickinson18,
E.B. Diehl103,J. Dietrich19,S. Díez Cornell44,A. Dimitrievska18,J. Dingfelder24,F. Dittus35, F. Djama99,
T. Djobava157b, J.I. Djuvsland59a,M.A.B. Do Vale78c, M. Dobre27b,D. Dodsworth26,C. Doglioni94,
J. Dolejsi139,Z. Dolezal139, M. Donadelli78d,J. Donini37,A. D’onofrio90, M. D’Onofrio88,J. Dopke141,
A. Doria67a, M.T. Dova86,A.T. Doyle55, E. Drechsler51,E. Dreyer149,T. Dreyer51, M. Dris10, Y. Du58b,
J. Duarte-Campderros159, F. Dubinin108,A. Dubreuil52,E. Duchovni178,G. Duckeck112,
A. Ducourthial132, O.A. Ducu107,x,D. Duda113, A. Dudarev35, A.C. Dudder97, E.M. Duffield18,
L. Duflot128,M. Dührssen35, C. Dülsen180, M. Dumancic178,A.E. Dumitriu27b,e, A.K. Duncan55,
M. Dunford59a, A. Duperrin99,H. Duran Yildiz4a, M. Düren54,A. Durglishvili157b,D. Duschinger46,
B. Dutta44, D. Duvnjak1,M. Dyndal44, B.S. Dziedzic82,C. Eckardt44,K.M. Ecker113,R.C. Edgar103,
T. Eifert35, G. Eigen17,K. Einsweiler18,T. Ekelof170, M. El Kacimi34c, R. El Kosseifi99,V. Ellajosyula99,
M. Ellert170,F. Ellinghaus180,A.A. Elliot90, N. Ellis35,J. Elmsheuser29, M. Elsing35, D. Emeliyanov141,
Y. Enari161, J.S. Ennis176,M.B. Epland47,J. Erdmann45, A. Ereditato20,S. Errede171,M. Escalier128,
C. Escobar172,B. Esposito49,O. Estrada Pastor172, A.I. Etienvre142,E. Etzion159, H. Evans63,
A. Ezhilov134,M. Ezzi34e,F. Fabbri55,L. Fabbri23b,23a, V. Fabiani117, G. Facini92,
R.M. Faisca Rodrigues Pereira136a,R.M. Fakhrutdinov140, S. Falciano70a, P.J. Falke5, S. Falke5,
J. Faltova139,Y. Fang15a, M. Fanti66a,66b, A. Farbin8, A. Farilla72a, E.M. Farina68a,68b,T. Farooque104,
S. Farrell18, S.M. Farrington176,P. Farthouat35, F. Fassi34e,P. Fassnacht35, D. Fassouliotis9,
M. Faucci Giannelli48, A. Favareto53b,53a,W.J. Fawcett52,L. Fayard128,O.L. Fedin134,q, W. Fedorko173,
M. Feickert41, S. Feigl130, L. Feligioni99, C. Feng58b,E.J. Feng35, M. Feng47,M.J. Fenton55,
A.B. Fenyuk140,L. Feremenga8,J. Ferrando44, A. Ferrari170, P. Ferrari118,R. Ferrari68a,
D.E. Ferreira de Lima59b, A. Ferrer172, D. Ferrere52, C. Ferretti103, F. Fiedler97,A. Filipˇciˇc89,
F. Filthaut117, M. Fincke-Keeler174,K.D. Finelli25, M.C.N. Fiolhais136a,136c,b,L. Fiorini172, C. Fischer14,
W.C. Fisher104,N. Flaschel44,I. Fleck148,P. Fleischmann103,R.R.M. Fletcher133,T. Flick180,
B.M. Flierl112,L.M. Flores133, L.R. Flores Castillo61a, N. Fomin17, G.T. Forcolin98, A. Formica142,
F.A. Förster14, A.C. Forti98,A.G. Foster21, D. Fournier128, H. Fox87,S. Fracchia146,P. Francavilla69a,69b,
M. Franchini23b,23a,S. Franchino59a, D. Francis35, L. Franconi130, M. Franklin57, M. Frate169,
M. Fraternali68a,68b, D. Freeborn92,S.M. Fressard-Batraneanu35,B. Freund107,W.S. Freund78b,
D. Froidevaux35,J.A. Frost131,C. Fukunaga162,T. Fusayasu114,J. Fuster172, O. Gabizon158,
A. Gabrielli23b,23a, A. Gabrielli18,G.P. Gach81a,S. Gadatsch52, P. Gadow113, G. Gagliardi53b,53a,
L.G. Gagnon107,C. Galea27b, B. Galhardo136a,136c, E.J. Gallas131,B.J. Gallop141,P. Gallus138,G. Galster39,
R. Gamboa Goni90, K.K. Gan122,S. Ganguly178,Y. Gao88,Y.S. Gao150,m,C. García172,
J.E. García Navarro172,J.A. García Pascual15a,M. Garcia-Sciveres18,R.W. Gardner36,N. Garelli150,
V. Garonne130, K. Gasnikova44,A. Gaudiello53b,53a, G. Gaudio68a, I.L. Gavrilenko108, A. Gavrilyuk109,
C. Gay173,G. Gaycken24,E.N. Gazis10,C.N.P. Gee141, J. Geisen51, M. Geisen97,M.P. Geisler59a,
K. Gellerstedt43a,43b,C. Gemme53b,M.H. Genest56, C. Geng103,S. Gentile70a,70b, C. Gentsos160,
S. George91,D. Gerbaudo14,G. Gessner45, S. Ghasemi148, M. Ghneimat24,B. Giacobbe23b,
S. Giagu70a,70b,N. Giangiacomi23b,23a,P. Giannetti69a, S.M. Gibson91, M. Gignac143, D. Gillberg33,
G. Gilles180,D.M. Gingrich3,au, M.P. Giordani64a,64c, F.M. Giorgi23b,P.F. Giraud142,P. Giromini57,
G. Giugliarelli64a,64c,D. Giugni66a, F. Giuli131,M. Giulini59b, S. Gkaitatzis160,I. Gkialas9,j,
E.L. Gkougkousis14, P. Gkountoumis10,L.K. Gladilin111,C. Glasman96, J. Glatzer14,P.C.F. Glaysher44,
A. Glazov44,M. Goblirsch-Kolb26,J. Godlewski82,S. Goldfarb102,T. Golling52,D. Golubkov140,
A. Gomes136a,136b,136d,R. Goncalves Gama78a, R. Gonçalo136a,G. Gonella50, L. Gonella21,
A. Gongadze77,F. Gonnella21, J.L. Gonski57,S. González de la Hoz172, S. Gonzalez-Sevilla52,
L. Goossens35,P.A. Gorbounov109,H.A. Gordon29,B. Gorini35,E. Gorini65a,65b, A. Gorišek89,
A.T. Goshaw47, C. Gössling45, M.I. Gostkin77, C.A. Gottardo24, C.R. Goudet128, D. Goujdami34c,
A.G. Goussiou145, N. Govender32b,c,C. Goy5,E. Gozani158,I. Grabowska-Bold81a,P.O.J. Gradin170,
E.C. Graham88,J. Gramling169, E. Gramstad130,S. Grancagnolo19, V. Gratchev134,P.M. Gravila27f,
C. Gray55, H.M. Gray18, Z.D. Greenwood93,aj,C. Grefe24, K. Gregersen92, I.M. Gregor44,P. Grenier150,
K. Grevtsov44, J. Griffiths8,A.A. Grillo143, K. Grimm150,S. Grinstein14,z, Ph. Gris37,J.-F. Grivaz128,
