DARK MATTER LHC – ATLAS SEASON 2 · 2016. 5. 23. · Dark Ma*er Benchmark Models for Early LHC...
22
1 DARK MATTER LHC – ATLAS SEASON 2 Dan Levin, University of Michigan on behalf of the ATLAS Collabora<on LHCSKI 2016 the hunt continues...
Transcript of DARK MATTER LHC – ATLAS SEASON 2 · 2016. 5. 23. · Dark Ma*er Benchmark Models for Early LHC...
1
DARK MATTER LHC – ATLAS SEASON 2
DanLevin,UniversityofMichigan
onbehalfoftheATLASCollabora<on
LHCSKI2016
the hunt continues...
1. Directdetec+on:
èNuclearrecoilfromDMpar<cleinterac<onsExclusionlimitsby:PICO-2L,Xenon100,LUX,SuperCDMS,PICASSO...MarcSchumantalk
2. Indirectastrophysicaldetec+oneg,positronexcessHEAT,PAMELA,AMSasWIMP-WIMPannihila<on?see“SecondaryProduc+onastheoriginoftheCRPositronExcess”arXiv1410.7239ApJOlafReimertalk
3. Produc+onincolliders:ifDMpar<clesweaklyinteractwithSMèSearchforgenericdecaysignatures
2
PossibleDMPar<cleInterac<ons
q qXenon100 Gran Sasso
AMS
χχrecoilagainsttriggerableobjectX=W/Z,h,jet,γ,t,b
3
X
yourinterac<on
here
χ
-q
q
χχescapeundetectedàMissingET
EventSignature:qqàthing+nothing
SearchforDMwithMono-X
χχWIMPpairsproduc<ondescribedby:• SimplifiedModelswithISR• SimplifiedModelswithHiggs• LighteststableSUSYpar<cles• Effec<veFieldTheory
4
SimplifiedModels
Z/Amediator:genericweakinterac<onaxial-vector,vector,scalar,pseudoscalarFreeparameters:MZ’=mediatormassmΧ=WIMPmassgq,=mediator-SMcouplinggΧ=mediator-WIMPcouplingΓ=minimalwidthassumed(decaysonlytoDMpar<cles)
axial-vectorcase:
DarkMa*erBenchmarkModelsforEarlyLHCRun-2Searches:ReportoftheATLAS/CMSDarkMa*erForumarXiv:1507.00966
ReplacingEFTsasbenchmarksèEFTnotvalidatlargeQ2
DM predictions
ETmiss
AnalysisStrategy
5
1)Lookforacleansignature:highmomentumobjectwithlargeETmiss
2)backgrounds:datadrivenMC(normalizedwithControlRegions)
3)kinema<ccutsdefineSignalRegions4)countnumberofeventsinSignalRegions
èlookforexcessoverSMbackground
MaxBaak-CERN
arXiv1212.3352
7
MonoZ/W(hadronic)
EFTDimension7operatorVectormediatedmodel
TwoDMproduc<onmodelsconsidered:
MZ’=0-1TeVmΧ=0-0.5TeVgq,=0.25,gΧ=1
DMForumBenchmarks
Fi=fieldstrengthsforSMU(1),SU(2),SU(3)gaugegroups.
8
Selec<onEtmisstrigger>80GeVEtmiss>200GeVatleast1large(an<-ktR=1.0)jet:Pt>250GeVMjet=MZ/MW±15GeVnolooseleptonsàe,μPt>7GeV|η|<2.47,2.7substructurevariableD2(Pt)èdiscriminateW/ZfromQCD
Etmiss
MonoZ/WèhighEtmiss+boostedW/Z(fatjet)
Backgrounds
arXiv1409.6298
*D2=f(2-pnt/3-pnttrackcorrela<on)
D2example
Z(àνν)+jetsW(àlν)+jets
simultaneousprofilelikelihoodfitof3ControlRegionsconstrainsMC
9
Data&SMconsistent
MonoZ/WResults
limitonEFTsuppressionscaleM*vsMχ Vectormodel:limitsonsignalstrengthμ
systema<csdominatedbylargeRjetparametersmassresolu<onà10%D2scaleà5-10%
Z(ll)+jetsCR
Finalstate:hàbb+Etmisstwob-jets+Etmiss 10
ISRisYukawasuppressed...Model1:Simplified...massivevectormediatorw/baryonnumber radiatesHiggs,decaystoWIMPS(alsowithbaryonnumber) specifiedby:gq,gΧ,gZ’,MZ’,MΧ,mixinganglesinϑ:SMhtobaryonicHModel2(2HDM):vectormediator(Z’)+two-Higgs-doublet(fiveHiggses)
Z’àA0+regularHiggsh,A0àΧΧ(BR~1)specifiedby:gq,gΧ,MZ’,MAMΧh–Hmixingangleα&tanβassumesalignmentlimitàcos(α-β)=0
MonoHiggs(hàbb)
Model1: Model2:
11
Selec<on• Etmisstrigger>80GeV• Etmiss>150GeV,Ptmiss>30GeVcentralregion,leptonveto• resolvedregion:Etmiss<500GeVàtwocentraljets,R=0.4,2b-tag)• mergedregion:Etmiss>500GeVàonelargeRjet(w/btag+2trackjets)• Δφ(Etmiss,Ptmiss)<π/2àsuppressfakeEtmiss
• Δφ(Etmiss,h)>120osuppressQCDdi-jets• Δφ(jet1,jet2)<140• B-tageff=70%,mis-ID=12%
MonoHiggs(hàbb)
14%-50%
78%-39%
1%-10%
SignalEventEtmiss=213GeVMjj=120GeV
bkgfrac<on
doprofilefittoMinvinHiggswindowforallCR,SR
12
MonoHiggs
dijetinvariantmass(2b-tag)350<Etmiss<500GeVShowingsignaltemplate
Etmissallsignalregions
13
MonoHiggsResults
çLimitsonWIMPMass–forVectorMediatormodel
LimitsonZ’+2DHMModelèpseudo-scalarAHeavyHiggsmassvsVectorMediatormasslimitsto500GeVonA
specifiedby:gq=1/3gΧ=1,gZ’=MZ’sinϑ=0.3
WIMPsignals(Powheg-Boxv2)S-channel,spin-1mediator@NLOB-Wpropagator,gΧ=1,gq=0.25masspointsgrid1GeV<MΧ<1TeV10GeV<MA<2TeV
Monojets
14
CompressedSUSYscenario:(Madgraph-5_aMC@NLO)stop,sbo�om,squarkpairs:250GeV<Msquark<700GeV5GeV<Δm=m~q1–m~Χ1<25GeV
15
MonojetAnalysis
processfrac<onEtmiss>250,700GeVZàνν+jets 58%,65%Wàνl+jets 35%,23%Z/γàll+jetsmul<jet,t,�dibosonnon-collision
7%,12%
Backgrounds(MC+3ControlRegions)• Etmisstrigger• Jetsreconswan<-ktR=0.4• primaryvertexinbeamspot• Etmiss>250GeV7signalregionsto700GeV• Pt(jetleading)>250GeV|η|<2.4• Pt/Etmiss>0.5• Δφ(Ptjet,Ptmiss)>0.4foralljets• vetoleptons(e/μ)>20/10GeV• veto:>4jets(Pt>30GeV)
SignalSelec<on
ExampleControlRegion:Zàνν+jetsbkg:useW(àμν)+jets:select30<MT<100GeV MT=
TransferfactorfromCRtoSR
MonojetControl&SignalRegions
SignalRegion>250GeV
16
removesleptonveto
Alas...onlySM!
Wàμν+jetscontrolregion
systema<cs:jet,Etmissenergyscale1.6%jetquality,pileup0.9%leptonID<2.6%W/Z+jetsmodeling2%-4%
17
MonojetSUSYDM
exclusionlimitsonstopmassextendedWRTtoRun-1
exclusionlimitsonsquarkmassMsquarkexcludedbelow602GeV(extendspreviouslimits)
18
MonojetWIMPLimits
EFT:D5
SimplifiedModellimits• excludeupto1TeVinmediatormass• RelicabundancebasedonWMAP,Planckassumesonlythespecifiedinterac<on• belowrelicabundancecurve:DMoverproduc<on• above‘’‘’underproduc<on
SimplifiedModelcrosssec<onlimitsexpressedasDirectDetec<onlimits
onshell
Signals
dimension-7EFToperator(sameasMono-Zwithk1=k2=1
EventSelec<onγtrigger70geV(99.7%eff)jecprimaryvertex,>2tracksat0.4GeVPhotonPT>150GeVETmiss>150GeVleadingγ|η|<2.37Δϕ(γ,Etmiss)>0.40or1jetPT>30GeV|η|<4.5Leptonveto
19
Monoγ
arXiv1212.3352
SimplifiedmodelAxial–vectorwithgΧ=1gq=0.25
Signalacceptance0.43-0.55
20
MonoγResultsEv
ents
/ 15
0 G
eV
1<10
1
10
210
310data
a)i lAW(Fake Photons
a ll)AZ(a)iiAZ(
+ jetsa
PreliminaryATLAS
-1=13 TeV, 3.2 fbs
Single-muon CR
[GeV]missTE
150 200 250 300 350 400 450 500 550 600
Dat
a/Bk
g
0.51
1.5
Even
ts /
150
GeV
1<10
1
10
210
310
410 dataDM150 M500
a)iiAZ(a)i lAW(
Fake Photons + jetsa
a ll)AZ(
PreliminaryATLAS
-1=13 TeV, 3.2 fbs
Signal Region
[GeV]missTE
150 200 250 300 350 400 450 500 550 600
Dat
a/Bk
g
0.51
1.5
BackgroundsZ+ISR→νν+γCRW+ISR→νll+ γCRZ→ll+ γCRZ/W+jets�,γ+jets,mul<jets:datadriven3ControlRegion:Invert1or2vetosàusetonormalizetheW+γ&Z+γMC
SinglemuonWàlνControlRegionSignalRegion
21
MonoγResults
[GeV]medm100 200 300 400 500 600 700 800
[GeV
]r
m
50
100
150
200
250
300
350 PreliminaryATLAS
-1=13 TeV, 3.2 fbs
Axial-vector mediator
Dirac DM
=1DM
g=0.25, qg
Observed 95% CLtheom 1 ±Observed
Expected 95% CLm 1±Expected
Relic densityPerturbative limit
[GeV]rm10 210 310 410
]2-p
roto
n cr
oss
sect
ion
[cm
r
43<10
42<10
41<10
40<10
39<10
38<10
37<10
36<10
35<10
34<10 PreliminaryATLAS-1=13 TeV, 3.2 fbs
90% CL limits
Axial-vector mediator
=1DM
g=0.25, qgDirac DM,
PICO-2L
XENON100
LUX
[GeV]rm1 10 210 310
[GeV
]*
95%
CL
low
er li
mit
on M
100200
300400500
600700
800900 observed limit
expected limitm 1±expected m 2±expected
truncated limits
ATLAS PreliminaryEW EFT model
= 13 TeV,s -13.2 fb
2
4 8
/4
truncatedlimitsonsuppressionscaleM*requiresECM<g*M*
σ(χ+P)limitsforA-Vsimplifiedmodelè
ConclusionFirstATLASsearchesat13TeV&3.2o-1forDMsignatureswithmono-higgs,photon,W/Z,jets,finalstatesNoexcessinSignalRegionsècompa<blewithSMLimitsaresetforDarkMa�erForumbenchmarksimplifiedmodelsdijetlimits:derivedfromcomparisonofgeneratedmediatormassesto95%CLdijetσ*Avsmjj(SeetalkbyDavidSalek)
22
MonoZ/W...ATLAS-CONF-2015-080Monojets....ATLAS-CONF-2016-011Monophoton....arxiv1604.01306MonoHiggs....ATLAS-CONF-2016-019
