SUSY Searches at ATLAS PauldeJong1,a,onbehalfoftheATLASCollaboration Nikhef,P.O.Box41882,NL-1009DBAmsterdam 2 Abstract. RecentresultsofsearchesforsupersymmetrybytheATLAScollaborationinupto2fb 1of √s=7 − 1 TeV ppcollisionsattheLHCarereported. 0 2 n 1 Introduction MSUGRA/CMSSM: tanβ = 10, A = 0, µ>0 Lint = 1.34 fb-1 a 0 J eV]550 ATLAS obs. CLs 95% C.L. limit 22 Dhausedtiosctohveehryigphocteennttirael-ofof-rmneawssheenaevrgyypoarfti7clTeesVb,etyhoenLdHthCe [Gm1/2500 MMuullttiijjeettss pplluuss EEmTmTiissss CCoommbbiinneedd 2eexx0pp1..1 Cl ≥im2L,si3t 9,±451 %j σe tCs .pLl.u lsim Eimtiss ] Tpaervtaictruolnarlfimoritpsaretvicelneswwitihthlictotlleoulurmchinarogseit,ys.uTchhiasshsoqludasrkins 450 q (~1400) CLELsP 9 25 %∼χ ± C.L. limit T p-ex atsoenndthsigetlievuxiitncyeolsalelisnnotsleuuxpmiesirtnssoyfsmoitrmyepeleetrcryftro(orSwmUeaSankYce)por[o1fd]th.ueHctLoioHwnCevoiefnrc,2hd0au1re1-, 345000 q ~(1000) ~g (1000) DTCh0De F~go, ~ rg~qe,,~qt i1t,ca tanalβlny=β e=3x,5 cµ, lµu 0,arisingfromtheanal- 0 1 ysiswith 2, 3or 4jetsplusmissingmomentum,andthe : 2 Searches with jets and missing multijetsp≥lusm≥issing≥momentumanalysis. v momentum i X r AssumingconservationofR-parity,thelightestsupersym- inasemi-data-drivenway,usingcontrolregionsincombi- a metricparticle(LSP)isstableandweaklyinteracting,and nationwithatransferfactorobtainedfromsimulation. will typically escape detection. If the primary produced The results are interpreted in the MSUGRA/CMSSM particles are squarks or gluinos (and assuming a negligi- model,andinparticularaslimitsintheplanespannedby blelifetimeoftheseparticles),thiswillleadtofinalstates the common scalar mass parameter at the GUT scale m0 with energeticjetsandsignificantmissingtransversemo- andthecommongauginomassparameterattheGUTscale mentum. m1/2, for values of the commontrilinear couplingparam- ATLAScarriesoutanalyseswithaleptonveto[2],re- eter A0 = 0, Higgs mixingparameter µ > 0, and ratio of quiring one isolated lepton [3], or requiring two or more the vacuumexpectationvaluesof the two Higgsdoublets leptons [4]. In addition, a dedicated search is performed tanβ=10.Figure1showstheresultsfortheanalyseswith foreventswithhighjetmultiplicity[5].Datasamplescor- 2, 3 or 4 jets plus missing momentum, and the ≥ ≥ ≥ responding to luminosities between 1.0 and 1.3 fb 1 are multijets plus missing momentum analysis. For a choice − used. Events are triggered either on the presence of a jet of parametersleadingto equalsquarkandgluinomasses, plus large missing momentum, or on the presence of at squarkandgluinomassesbelowapproximately1TeVare leastonehigh-p lepton.Backgroundstothesearchesarise excluded. The 1-lepton and 2-lepton results are less con- T fromStandardModelprocessessuchasvectorbosonpro- straininginMSUGRA/CMSSMforthischoiceofparam- ductionplusjets (W + jets, Z + jets), top quarkpair pro- eters,buttheseanalysesarecomplementary,andtherefore duction and single top production,QCD multijet produc- nolessimportant. tion, and diboson production.Backgroundsare estimated The search with two isolated opposite-chargeleptons isalsointerpretedintheframeworkofminimalgaugeme- a e-mail:paul.de.jong@nikhef.nl diatedsupersymmetrybreaking(GMSB),asshowninFig- EPJWebofConferences GMSB: M =250TeV, N=3, sign(µ) = +, C =1 Squark-gluino-neutralino model βn 50 mes 5 grav V]2000 ATLAS Preliminary ta ATLAS Preliminary Observed 95% CL Ge 0 lepton 2011 combined 3400 Theory excl. Lint = 1.0MOLLE4EExP efpPPdAbe iL99a-c1 55nt,9e%% 5e d% x CClspi mLLCe= cLi((7 tt∼~τe .± 1 RT)9 )15eσ%V CL ark mass [11570500 ∫ L dt = 1.04EEOO xxfbbbppss-..1.., mmmmsLLLLSS=SSPPPP7 == ==T e0101V 9 9GG55e e GGVVeeVV OS combined EmTiss + 3 jets qu EOxbps.. mmLSP == 339955 GGeeVV s1250 LSP 1200 χ∼10 ∼τC1oNLSP ~ lR 1705000 Tevatron, Run I CDF, Run II D0, Run II σσSSUUSSYY == 00..10 1p pbb 10 20 30 40 50 60 Λ [TeV7]0 σSUSY = 1 pb 500 Fig. 2. Exclusion contours in the GMSB Λ-tanβ plane, for σSUSY = 10 pb M =250TeV,N =3andµ>0,resultingfromtheopposite- 250 chmaregseleptonanalys5is. LEP2 ~q 0 0 250 500 750 1000 1250 1500 1750 2000 gluino mass [GeV] ure2[6].Assumingamessengermassscale M of250 mes Fig.3. Exclusioncontours inthesquark-gluino massplane, for TeV, 3 generations of messengers (N = 3) and µ > 0, 5 three values of the LSP mass, using the simplified model de- limitsaresetontheeffectiveSUSY breakingscaleΛ and scribedinthetext. ontanβ.TheselimitssignificantlyimproveontheLEPre- sults. ∼∼ Direct decay, ~g~g ⇒ qqqqχ0χ0 V]1000 11 102 b] 3 Simplified model interpretation mass [Ge 890000 ∫0A0 LllTee dppLttt oo=Ann 1 22S.000411 11 Pf bcc-r1oo,e mmlsbbi=miinn7ee TiddneVary % C.L. [p ATLAShasfounditusefultonotonlyinterprettheresults P CLs observed 95% C.L. limit 10 95 ienlscaosnssutrmaiinnegdsmpeocdifielcs,pbruotdaulcstoioinnatenrdmdseocfasyimmpoldifieesd[7m].oIdn- LS 670000 CExLps emceteddia lnim eitx ±p1e cσted limit ded at seulsclhikseimMpSliUfiGedRmA/oCdMelsS,StMheocroGnsMtrSaiBntasreimrepllaixededb,yleamvoindg- 500 ~g LS P exclu more freedom for variation of particle masses and decay 400 1 BR) modes.Interpretationsinsimplifiedmodelsthusshowbet- × 300 σ terthelimitationsoftheanalysesasafunctionoftherel- ( evantkinematicvariables,andaidindrawingconclusions 200 10-1 fromtheresults. 100 Inclusivesearchresultswithjetsandmissingmomen- tumareinterpretedusingsimplifiedmodelswitheitherpair 0 300 400 500 600 700 800 900 1000 productionofsquarksorofgluinos,orproductionofsquark- gluino mass [GeV] gluinopairs.Directsquarkdecays(q˜ qχ˜0)ordirectglu- 1 ino decays (g˜ qq¯χ˜0) are dominan→tif all other particle Fig.4.Crosssectionlimitsandexclusioncontoursinthegluino- masses have m→ulti-TeV1 values, so that those do not play neutralinomassplane,fordirectgluinodecays,g˜ →qq¯χ˜01,asob- tainedbytheno-leptonanalysis.Allsquarkmassesareassumed arole.Additionalcomplexitymaybebuiltin,forexample byallowingone-stepdecaystointermediatecharginos,χ˜±, tobemulti-TeV,sothatonlygluinopairproductiontakesplace, and thedirect decay isassumed tooccur with100% branching orheavierneutralinos,χ˜0. 2 fraction. Figure3showstheATLASresultsinterpretedinterms of limits on (first and secondgeneration)squark and glu- inomasses,forthreevaluesoftheLSP(χ˜0)mass,andas- 1 catethatmassesoffirstandsecondgenerationsquarksand sumingthatallotherSUSYparticlesareverymassive[8]. ofgluinosmustbeaboveapproximately750GeV.Anim- Furtherinterpretationsaredoneintermsoflimitsongluino portant caveat in this interpretation is the fact that this is massvsLSPmassassuminghighsquarkmasses,asshown onlytrueforneutralinoLSPmassesbelowapproximately for example in Figure 4 for direct decays, or in terms of 250GeV(asinMSUGRA/CMSSMforvaluesofm be- 1/2 limitsonsquarkmassvsLSPmassassuminghighgluino low (600)GeV).ForhigherLSPmasses,thesquarkand masses [3,8]. Figure 5 shows an example of limits in the O gluinomasslimitsaresignificantlylessrestraining.Itwill gluino-LSPmassplaneobtainedfromone-stepgluinode- be a challengefor furtheranalysesto extendthe sensitiv- cays,g˜ qq¯′χ˜±, χ˜± W(∗)χ˜01,bytheone-leptonanaly- ity of inclusive squark and gluino searches to the case of → → sis.Thecharginomassinsuchdecaysisafreeparameter, heavyneutralinos.If the LSPis heavy,eventsare charac- characterizedbyx=(mχ˜±−mχ˜01)/(mg˜−mχ˜01),andFigure5 terized by less energetic jets and less missing transverse showsx=1/2asanexample. momentum.This will be more difficult to trigger on, and The results of the inclusivejets plusmissing momen- lead to higherStandard Modelbackgroundsin the analy- tumsearches,interpretedinthesesimplifiedmodels,indi- sis. HadronColliderPhysicsSymposium2011 V] 800 b] [GemLSP 670000 ~LgC1~gi-noS→t m=teqb p1qin .qD0aq4etWi cofbanW-y1,,χ∼ x01s=χ∼=0117/2 TeV ATLAS 102at 95% CL [p m [GeV]∼0χ1330500 ~b1-~b1C pDroFd 2u.c6ti5o nfb, -~b11→ b+∼χ01 C±CC LLL1sss σ EOE NxxbppLseeOeccr vttseeecddda lLLeLii immmuniiitttc (±(.9 9155 σ%% CC..LL..)) 500 Observed 95% CL ded 250 D0 5.2 fb-1 ATLAS 340000 EExxppeecctteedd ±1σ 10 Section Exclu 125000 ~b →1 b ∼χ0 1forbidden ∫L dt = 2.05 fb-1, s = 7 TeV 1 s s 200 Cro 100 Reference point 100 10-1 50 0 300 400 500 600 700 800 0 100 150 200 250 300 350 400 450 mgluino [GeV] m~ [GeV] b 1 Fig.5.Crosssectionlimitsandexclusioncontoursinthegluino- Fig. 6. Exclusion contour inthesbottom-neutralino mass plane neutralino mass plane, for one-step gluino decays, g˜ qq¯′χ˜±, resultingfromtheanalysissearchingforsbottomquarkpairpro- χ˜± → W(∗)χ˜01,asobtainedbytheone-leptonanalysis.→Onlyglu- duction,assumingsbottomtobottomplusneutralinodecay. inopairproductionisconsidered,theone-stepgluinodecayisas- sm4uamSsseUdisStcohYoacraaccuntredrwizintehda1bt0yu0x%ra=bl1rna/ne2cs(hsisenegtferxatc)t.ion,andthechargino [GeV]m~t1556050000~g-~g 1>A>+-== ~lTte -11~tpL tpbboAr--nottaa,dS gg4u,, c jmmePtitoeesrffnff e,>> ~g l66 i→00m00 ~t iGG1+neet,aVV ~tr1→y b+χ∼±1 OECCExxLLbppsss∫ eeoeeLccbxrdtvtpseeteee dd=drc vC AtA1eeTL.Tdd0sLL 3llAliiAim mmfSSbiiit t-t (1 (,3±3 515sσ p=pb7b--11 )T)eV 450 m(χ∼0) = 60 GeV , m(χ∼±) ≈ 2 m(χ∼0) 1 1 1 ItrmypaorretatnhtemfaocttivsatthioatnsSUfoSrYelemctirgohwteparko-vsicdaeleasnuapteurrsaylmsomlue-- 334050000 m(~q1,2) >> m(~g) ~g → ~tt1 forbidden tion to the hierarchy problem by preventing “unnatural” 250 fine-tuning of the Higgs sector, and that the lightest sta- bleSUSYparticleisanexcellentdarkmattercandidate.It 200 Reference point isinstructivetoconsiderwhatsuchamotivationreallyre- 150 quiresfromSUSY:arelativelylighttopquarkpartner(the 300 350 400 450 500 550 600 650 700 750 800 stop, t˜) (and an associated sbottom-leftquark, b˜ ), a glu- mg~ [GeV] L inonotmuchheavierthanabout1.5TeVtokeepthestop Fig.7.Exclusioncontourinthegluino-stopmassplaneresulting light (the stop receives radiative corrections from loops fromtheanalysissearchingfor stopquark production ingluino liket˜ g˜t t˜),andelectroweakgauginosbelowtheTeV decays.Theassumptionsmadetoderivetheplotarelistedinthe scale→[9].Th→erearenostrongconstraintsonfirstandsec- plot. ondgenerationsquarksandsleptons;infactheavysquarks andsleptonsmakeiteasierforSUSYtosatisfythestrong constraintsfromflavourphysics.Motivatedbythese con- a neutralino (LSP) with a 100% branching fraction. Un- siderations,ATLASexplicitlysearchesforthirdgeneration dertheseassumptions,sbottommassesupto390GeVare squarksandforelectroweakgauginos. excludedforneutralinomassesbelow60GeV. ATLAShassearchedforstopquarkproductioninglu- ino decays [12] using an analysis requiring at least four high-p jetsofwhichatleastoneshouldbeb-tagged,one T 5 Stop and sbottomsearches isolatedlepton,andsignificantmissingtransversemomen- tum.Afterapplyingtheselectioncriteria,74eventsareob- ATLAS has carried out a number of searches for super- servedin1.0fb−1ofdata,where55 14backgroundevents ± symmetrywith b-taggedjets, which are sensitive to sbot- are expected from a data-driven estimation procedure, or tom and stop quarks production, either direct, or in glu- 52 28 from Monte Carlo simulations. Since there is no ± inodecays.Jetsaretaggedasoriginatingfromb-quarksby significant excess, limits are set in the gluino-stop mass analgorithmthatexploitsbothtrackimpactparameterand plane,assumingthegluinotodecayasg˜ t˜t,andthestop secondaryvertexinformation. quarktodecayast˜ bχ˜±1,asshowninF→igure7. → Directsbottompairproductionissearchedforinadata Inaddition,ATLAShassearchedforsbottomproduc- samplecorrespondingto2fb 1 byrequiringtwob-tagged tionin gluinodecays,setting limitsinthegluino-sbottom − jetswith p > 130,50GeVandsignificantmissingtrans- massplaneandinthegluino-neutralinomassplane[13]. T versemomentumofmorethan130GeV[10].Thefinaldis- Furthersearches for directstop quarkpair production criminantistheboost-correctedcontransversemassm [11], areinprogress.Thesesearchesarechallengingduetothe CT andsignalregionswithm >100,150,200GeVarecon- similaritywiththetopquarkpairproductionfinalstatefor CT sidered.Noexcessesareobservedabovetheexpectedback- stop masses similar to the top mass, and due to the low groundsoftop,W+heavyflavourandZ+heavyflavourpro- cross section for high stop masses. ATLAS has searched duction.Figure6showstheresultinglimitsinthesbottom- forsignsofnewphenomenaintopquarkpaireventswith neutralino mass plane, assuming sbottom quark pair pro- large missing transverse momentum [14]; such an analy- ductionandsbottomquarkdecayintoabottomquarkplus sis is sensitive to pair production of massive partners of EPJWebofConferences m [GeV]~g111102000000GGM: bin±AAAo TTT1-LLLl iσAAAkeSSS nCCCeLLLussst oreoabxblpssineeeorcrvvt,eee tddda 9n995β55%%% = CCC2LLL, cllliiimmmτNiiitttL S(3P6 < pA b0.T-11)L mAmS [GeV]m∼0χ1330500 χ∼±1∫ mχ∼L∼χ02 ±1d →=t =m ~ lν1∼χ02. ~,0l lm,4 l~ lν∼,fν∼b ~=l-l1 , → m Ls Sl=νP7 +χ∼ T 011e l/Vl2 χ∼ (01m∼χ±1 - m∼χ01) 345345 % CL [pb]% CL [pb] CMS observed 95% CL limit (35 pb-1) Observed 95% CL 22 9595 900 250 Expected at at Expected ± 1 σ d d 800 ∫Ldt = 1.07 fb-1 200 ATLAS 11 cludeclude 700 xx s = 7 TeV 150 n En E 600 oo 500 ~g NLSP 100 s Sectis Secti 400 200 400 600 800 1000 1200 50 CrosCros mχ∼ [GeV] 0 150 200 250 300 350 00..22 m∼χ±,∼χ0 [GeV] 1 2 Fig.8.Exclusioncontourinthegluino-neutralinomassplanein Fig. 9. Cross section limits and exclusion contours in the thegeneralgaugemediation(GGM)model,assumingabino-like chargino-neutralino massplane,resultingfromthesame-charge neutralino,resultingfromthediphotonplusmissingmomentum dilepton analysis. The interpretation is done in a simplified analysis. model,detailsaregivenintheplot. the top quark, decaying to a top quark and a long-lived undetected neutral particle. No excess above background selectioncriteriaonjetsandonthemissingtransversemo- wasobserved,andlimitsonthecrosssectionforpairpro- mentum. For all signal regions, the observed event count duction of top quark partners are set. These limits con- agreeswiththeexpectedbackground.Theanalysisselect- strain fermionic exotic fourth generation quarks, but not ing same-chargeleptonspluslargemissing momentumis yetscalarpartnersofthetopquark,suchasthestopquark. sensitive to electroweak gaugino production, and results for this analysis are shown in Figure 9. The interpreta- tionisdoneinasimplifiedmodelassumingchargino(χ˜±1) 6 Electroweakgaugino searches plusaheavierneutralino(χ˜0)production,anddecaytolep- 2 tonsandLSPsthroughintermediatesleptons.Undertheas- Searchesforcharginosandneutralinosarecarriedoutvia sumptionofequalmassofχ˜±1 andχ˜02,limitsaresetinthe amneanlytusmes,oofrfimnualltsilteaptetsoninsvpolluvsinmgipsshiontgonmsopmluesnmtuimss.ingmo- χ˜±1 −χ˜01massplane. Ingaugemediationmodels,neutralinosdecaytograv- itinosplusoneormorestandardmodelparticles,depend- 7 Specialfinal states ing on the neutralinocomposition.For bino-likeneutrali- nos, the final state consists of a pair of high-p photons T ThenumberofdifferentfinalstatessensitivetoSUSYpro- plusmissingtransversemomentum.ATLAShassearched foranexcessinsuchfinalstatesusing1.1fb 1ofdata[15]. duction is very large. SUSY particles may be long-lived, − whentheirdecayissuppressedkinematically(splitSUSY, Theselectionrequirestwophotons,identifiedwith“tight” R-hadrons,anomaly-mediatedSUSYbreaking,certainparts criteria,with p > 25GeV,andsignificantmissingtrans- T of phase space of gauge-mediatedSUSY breaking)or by versemomentum.Theresultsareinterpretedinthegeneral verysmallcouplings(e.g.R-parityviolation).ATLAShas gauge mediation model (GGM), in terms of limits in the carried out searches for stable massive particles [17], for gluino-neutralinomassplane,andassumingtheneutralino stoppedgluinos[18],forkinkedordisappearingtracks[19] tobetheNLSP.TheresultsareshowninFigure8.Theas- andforsecondaryverticesofdecayingmassiveparticles[20]. sumptionismadethatphotonsareproducedpromptly,i.e. Furthermore,there is a dedicatedsearch for third genera- cτoftheNLSPisassumedtobelessthan0.1mm.Inthis tion sneutrinos decaying to an electron-muon pair in R- model,agluinomassbelow805GeVisexcludedforbino parity violation scenarios [21]. It is also noteworthy that massesabove50GeV. ATLAShassearchedforascalarpartnerofthegluon[22]. Thediphotonplusmissingtransversemomentumanal- Kinkedordisappearingtracksareapossiblesignature ysis is also interpreted in the minimal gauge mediation ofhigh-p massiveparticlesdecayinginthedetectorvol- model(GMSB),fortheSPS8parametersM =2Λ,N = T mes 5 ume to an almost degenerate daughter particle, such as 1,tanβ=15andµ>0.TheATLASresultsimplyalower limitonΛfortheSPS8parametersof145TeVat95%CL. χ˜±1 χ˜01π±inanomaly-mediatedSUSYbreaking(AMSB) Multileptonanalyses[4,16]aresensitivetoproduction mod→els, where χ˜±1 and χ˜01 are almost degenerate, and the ofcharginosand/orneutralinosotherthantheLSP,decay- resultingpiontrackhaslow p andiseasilymissedinthe T ing leptonically to the LSP. These analyses comprise the reconstruction. ATLAS has searched for such signatures goldensearch modesat the Tevatron,butare also rapidly in 1.0 fb 1 of data [19], demandinga track p of at least − T gaining relevance at the LHC. ATLAS searches for ex- 10 GeV, good reconstruction quality in the silicon track- cessesinfinalstateswiththreeormoreleptonsonthe2011 ingdetectorsandintheinnerlayersofthetransitionradi- dataareinprogress.ATLAShaspublishedresultsofvar- ation tracker (TRT), but no, or only few hits in the outer ious analyses searching for dilepton events plus missing layerof theTRT. Backgroundsarise fromtracksinteract- momentum, in 1.0 fb 1 of data [4]. Three signal regions ing with the TRT material(dominant),or frommisrecon- − aredefinedforopposite-chargeleptons,andtwosignalre- structed low-p tracks. Figure 10 (top)shows probability T gions are defined for same-charge leptons, with varying density functions (pdfs) in p for signal and background T HadronColliderPhysicsSymposium2011 bability density1100-1-21 ATLAS Prelims=i7nTaerVy SHBiaagddn ratorlan: c LtkrLa 0bc1ak,c bτk(agχ∼cr±1ok) ug=nr o1dunnsd x mass [GeV]102 ×111..460-3 Pro10-3 Verte 1.2 1 10-4 Signal region 10 0.8 10-5 ATLAS ∫ 0.6 Ldt = 33 pb-1 10-6 102 103 0.4 track pT [GeV] 1 Data 2010 0.2 V102 Signal MC Ge Data 0 1 2 3 4 5 6 78910 20 30 40 s / 10 Fit results Number of tracks in vertex k c a Tr 1 ATLAS Preliminary Fig.11.Vertexmassandnumberoftracksinthesecondaryver- s=7TeV, ∫Ldt = 1.02 fb-1 tex,forverticesselectedbytheanalysissearchingforhighmass 10-1 secondaryvertices. 10-2 in triggering,andindealingwithhighpile-upconditions. Inthelongerterm,increasingtheLHCbeamenergyto>6 10-3 10 20 50 100 200 500 1000 TeVwillagainenablethecrossingofkinematicalbarriers track p [GeV] andopenthewayformulti-TeVSUSYsearches. T Fig. 10. Top: Probability density functions for signal (AMSB model) and expected background distributions of track p for T References trackssatisfyingthekinked-trackselection.Bottom:Distribution oftrack p for185tracksindatasatisfyingthekinked-trackse- T 1. See the reviews of S. P. Martin, hep-ph/9709356 and lection,andtheresultofthepdffit.Thefitisconsistentwiththe H. P. Nilles, Phys. Rept. 110 (1984) 1, and references background-onlyhypothesis. therein. 2. ATLASCollaboration,arXiv:1109.6572(2011) tracks;Figure10(bottom)showsthe p distributionofthe 3. ATLASCollaboration,arXiv:1109.6606(2011) T 185tracksindatasatisfyingtheselectioncriteria,andthe 4. ATLASCollaboration,arXiv:1110.6189(2011) pdf fit to the data. The data is consistent with the back- 5. ATLASCollaboration,JHEP11(2011)99 groundexpectation,andupperlimitsonthesignalareset. 6. ATLAS Collaboration, ATLAS-CONF-2011-156 ATLAShasalsosearchedforhigh-masssecondaryver- (2011),http://cdsweb.cern.ch/record/1398247/ tices,consistentwiththedecayofmassiveparticles,in33 7. D.Alvesetal.,arXiv:1105.2838(2011) pb 1ofdatacollectedin2010.Theanalysisisdesignedin 8. ATLAS Collaboration, ATLAS-CONF-2011-155 − particularforthe decayχ˜0 µ˜µandthe R-parityviolat- (2011),http://cdsweb.cern.ch/record/1398201/ ingdecayµ˜ qq¯ through→anon-zeroλ coupling[20]. 9. R.Barbieri,these(HCP2011)proceedings → ′ ′2ij 10. ATLASCollaboration,arXiv:1112.3832(2011) Backgroundsarise from interactionsin the inner detector 11. G.PoleselloandD.Tovey,JHEP03(2010)030 material,andthefiducialvolumeofthisanalysisexcludes 12. ATLAS Collaboration, ATLAS-CONF-2011-130 regionswithsuchdetectormaterial.Asignalregionisde- (2011),http://cdsweb.cern.ch/record/1383833/ fined requiringa vertexmass of10 GeV or more,with at 13. ATLAS Collaboration, ATLAS-CONF-2011-098 leastfourtracksinthevertex,asshowninFigure11.The (2011),http://cdsweb.cern.ch/record/1369212/ dataisconsistentwiththebackgroundhypothesis. 14. ATLASCollaboration,arXiv:1109.4725(2011) 15. ATLASCollaboration,arXiv:1111.4116(2011) 16. ATLAS Collaboration, ATLAS-CONF-2011-039 8 Conclusion and Outlook (2011),http://cdsweb.cern.ch/record/1338568/ 17. ATLASCollaboration,Phys.Lett.B703(2011)428, The results of ATLAS supersymmetry searches are sum- Phys.Lett.B701(2011)1 marizedinFigure12. 18. ATLASCollaboration,(inpreparation) AlthoughnosignsofSUSYhavebeenfoundsofar,it 19. ATLASCollaboration,(inpreparation) isimportanttorealizethatactualtestsof“natural”SUSY 20. ATLASCollaboration,arXiv:1109.2242(2011) are onlyjustbeginning[23]. Inthisrespect, theLHC run 21. ATLASCollaboration,Eur.Phys.J.C71(2011)1809 of2012,withanexpectedluminosityofmorethan10fb−1, 22. ATLASCollaboration,Eur.Phys.J.C71(2011)1828 possibly at √s = 8 TeV, will be very important. How- 23. G.Polesello,these(HCP2011)proceedings ever,experimentallytherewillbeconsiderablechallenges EPJWebofConferences ATLAS SUSY Searches* - 95% CL Lower Limits (Status: Dec. 2011) MSUGRA/CMSSM : 0-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6572] 950 GeV ~q = ~g mass ATLAS MSUGRA/CMSSM : 1-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6606] 820 GeV ~q = ~g mass Preliminary MSUGRA/CMSSM : multijets + ET,miss L=1.3 fb-1 (2011) [arXiv:1110.2299] 680 GeV ~g mass (for m(~q) = 2m(~g)) ∫ Simpl. mod. : 0-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6572] 1.075 TeV ~q = ~g mass (light χ∼01) Ldt = (0.03 - 2.0) fb-1 Simpl. mod. : 0-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6572] 875 GeV ~q mass (m(~g) < 2 TeV, light χ∼01) s = 7 TeV Simpl. mod. : 0-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6572] 700 GeV ~g mass (m(~q) < 2 TeV, light χ∼01) Simpl. mod. : 0-lep + j’s + ET,miss L=1.0 fb-1 (2011) [ATLAS-CONF-2011-155] 700 GeV ~q mass (m(~g) < 2 TeV, m(χ∼01) < 200 GeV) Simpl. modS. i(m~g→pl. qmqoχ∼d±). :: 10--lleepp ++ jj’’ss ++ EETT,,mmiissss LL==11..00 ffbb--11 ((22001111)) [[AarTXLiAv:S1-1C0O9.N6F60-260]11-155] 60605 0G GeVe V ~g~g m maassss ( m (m(χ∼(01~q)) < < 2 20 T0e GVe, mV,( ∆χ∼01m) (<χ∼ ±2,0 χ∼00 )G / e∆Vm)(~g, χ∼0) > 1/2) SUSY SimpSli.m mpoSlS.d imim.m (op~gpdl→l... mm(tχ∼toχ∼o±1dχ01∼d).02. ::(→ ~b101-- →ll3eelpp χ∼b 01χ+∼+)01 bb): --2:jj ee-2ltte ssbp -++ jSe jjtS’’sss ++++ EEEETTTT,,,,mmmmiiiissssssss LLLL====1120....0008 53ff bbffbb--11 --11(( 22((22001001111111)) ))[[ Aa[[PArTXrTLeiLAvlAi:Sm1S-1Ci-1nCO0aO.rN6yN1F]8F-229-020]001 G111-e1-V03 098]]χ∼3±19 0m Gae5Vs40 s G(7b~eli2V g0m h Gate~ gχ∼sV sm 01, (am~gms (m~s(l)χ∼ a (01=ms) 2s1(< (χ∼( m601m)0( (χ∼< b~G±1 )8) e <0+V G6m)0e(0χ∼V 02)G))e)V, lightχ∼ 01) GMSB : 2-lep OSSF + ET,miss L=1.0 fb-1 (2011) [ATLAS-CONF-2011-156] 810 GeV ~g mass (corresp. to Λ < 35 TeV, tanβ < 35) GGM + Simpl. model : γγ + ET,miss L=1.1 fb-1 (2011) [arXiv:1111.4116] 805 GeV ~g mass (m(bino) > 50 GeV) GMSB : stable ∼τ L=37 pb-1 (2010) [1106.4143965 ]GeV ∼τ mass AMSB : long-lived χ∼±1 L=1.0 fb-1 (2011) [9P2r eGle]V χ∼±1 mass (0.5 < τ(χ∼±1) < 2 ns ) Stable massive particles : R-hadrons L=34 pb-1 (2010) [arXiv:1103.1984] 562 GeV ~g mass ~ Stable massive particles : R-hadrons L=34 pb-1 (2010) [arXiv:1103.1984] 294 GeV b mass Stable massive particles : R-hadrons L=34 pb-1 (2010) [arXiv:1103.1984] 309 GeV ~t mass Hypercolour scalar gluons : 4 jets, mij ≈ mkl L=34 pb-1 (2010) [arXiv:1110.2168953 ]GeV sgluon mass (excl: msg < 100 GeV, m sg ≈ 140 ± 3 GeV) RPV : high-mass eµ L=1.1 fb-1 (2011) [arXiv:1109.3089] 1.32 TeV ν∼τ mass (λ,311=0.10, λ312=0.05) Bilinear RPV : 1-lep + j’s + ET,miss L=1.0 fb-1 (2011) [arXiv:1109.6606] 760 GeV ~q = ~g mass (cτLSP < 15 mm) 10-1 1 10 Mass scale [TeV] *Only a selection of the available results leading to mass limits shown Fig. 12. Summary of limitsset on SUSY particlemasses by ATLAS,resulting from analyses of up to2 fb 1 of pp collision data at − √s=7TeV.

SUSY Searches at ATLAS

Similar SUSY Searches at ATLAS