Shima Shimizu (Kobe U.) KUBEC DM workshop 7/Aug/014
Dark ma'er search with mono- X events If Dark Ma9er couples to Standard Model (SM) paracles, DM is searchable at collider experiments. Weakly interacang massive paracles (WIMPs), χ. WIMP pair producaon at collider. Direct search Indirect search (WIMP anihilaaon) SM SM DM DM Collider experiments Tag the pair- producaon system by the iniaal state radiaaon (ISR) of SM paracles, X: pp - > χχ + X WIMPs don t interact with the detectors. à Large ing transverse energy, q - X èsearch of Mono- X + q
Mono- X interpreta9ons EffecAve Field Theories (EFTs) Contact interacaon between SM paracles and DM, χ. Mediator is too heavy to be directly produced and is integrated out. Two parameters: Suppression scale: M * = M med / (g SM g DM ) Dark ma9er mass: m Χ M med : mediator mass g : coupling Spin- dependent interacaon Simplified models Mediator is not integrated out. Addressing validity quesaon of EFT at high energies.
detector Tracking system : η <.5 Calorimeter : η <4.9 Muon system : η <.7 Three- level trigger system 4
Available pp collision data s = 7 TeV: 5 e- 1 s = 8 TeV: 0 e- 1 MulAple interacaons occurs simultaneously in a colliding. Increased in 01 u Recorded Luminosity [pb/0.1] u 180 5 Preliminary 01, LHC Delivered 0 Recorded s = 8 TeV Delivered:.8 fb Recorded: 1. fb Physics: 0. fb Good for Physics 15 011, s = 7 TeV Delivered: 5.46 fb Recorded: 5.08 fb Physics: 4.57 fb 5 0 Jan Apr Jul Oct Jan Apr Online Luminosity 160 s = 8 TeV, Ldt = 1.7 fb, <µ> = 0.7 140 s = 7 TeV, Ldt = 5. fb, <µ> = 9.1 10 Z- >μμ event with 0 verfces 0 80 60 40 0 0 0 Total Integrated Luminosity fb data 5 0 5 15 0 5 0 5 40 45 Mean Number of Interactions per Crossing Jul Oct Month in Year
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7 u Event selecaons Large ET An energeac object (X) Veto on (extra) leptons Veto on >1 addiaonal jets Good separaaon in φ between ET, X and addiaonal jets
8 General analysis strategies Event selecaons Large An energeac object (X) Veto on (extra) leptons Veto on >1 addiaonal jets Good separaaon in φ between, X and addiaonal jets SM processes are background to the DM search. W/Z backgrounds e.g: Z- >νν or W- >lν with lepton outside of the acceptance, etc Usually esamated using control regions with lepton requirements. MulAjet backgrounds EsAmated by events with jet aligned with the direcaon. Diboson producaon, Top producaon Usually esamated based on MC simulaaon.
9 Mono- γ search Mono- jet search Mono- W/Z (hadronic) search Mono- W search Mono- Z search
Mono- γ search analysis s=7 TeV, 4.6 e - 1 PRL 1, 01180 (01) mono- γ Event selecaon Isolated, well- defined photon with p γ T > 150 GeV E T > 150 GeV Lepton veto N jet < for p jet T > 0 GeV Δφ(γ, E T ) > 0.4, Δφ(γ, jet) > 0.4, Δφ(E T, jet) > 0.4 Backgrounds W/Z + γ ß control region W/Z + jet ß esamaaon of fake γ from e or jet γ + jet, mulajet ß data Events / GeV 1 - - L dt = 4.6 fb Data 011 ( s =7 TeV) Z()+ W/Z+ W/Z+jet top, +jet, multi-jet, diboson Total background ADD NLO, M =1.0 TeV, n= D WIMP, D5, m = GeV, M =400 GeV * 150 00 50 00 50 400 450 500 (total) (total)
Mono- γ search results EFT operators D1, D5, D8 and D9 are considered. Limits set on M *, for a given m χ. à Converted to χ- nucleon cross- secaon limit for a comparison. mono- γ m χ = 1 GeV m χ = 1. TeV D1 M * > 1 GeV M * > 5 GeV D5 M * > 585 GeV M * > 156 GeV D8 M * > 585 GeV M * > 0 GeV D9 M * > 794 GeV M * > 188 GeV 11 ] -Nucleon cross section [cm -4-5 -6-7 -8-9 -40-90% CL, Spin Dependent -41-4 -4-44 -45 SIMPLE CDF, D8, q q j() 1 Dirac CMS (5 fb ), D8, qq (), D8, qq () Dirac, D9, qq () Dirac Picasso m Dirac s =7 TeV, Ldt = 4.6 fb 90% CL, Spin Independent XENON0 CDMS CoGeNT CDF, D5, qq j() CMS (5 fb ), D5, qq () Dirac, D5, q q () Dirac, D1, qq () 1 Dirac m Dirac Limits from collider experiment is compeaave at low m χ. Spin- dependent limits are smaller than the direct searches.
1 Mono- γ search Mono- jet search Mono- W/Z (hadronic) search Mono- W search Mono- Z search
Event selec9on (7TeV analysis) s=7 TeV, 4.6 e - 1 JHEP04 (01) 075 mono- jet 1 Event selecaon 4 Signal Regions (SR), p T jet,leading > 10, 0, 50 and 500 GeV ana- k t jet with R=0.4, η < No more than one addiaonal jet with p T >0 GeV, η <4.5 Δφ(p T, p T jet ) >0.5 Lepton vetos (loose definiaon for SR- leptons) Electron: p T >0 GeV, η <.47, Muon: p T >7 GeV, η <.5 Dominant background Z/W + jets CR is defined with explicit (Aght) lepton requirement ß EsAmated using Control Region (CR)
mono- jet 14 Results Dominant systemaac uncertainaes from: JES, TheoreAcal uncertainaes of W and Z producaon, shapes of W Good agreement with the SM predicaons Events/GeV 5 4 1 Ldt = 4.7 fb s= 7 TeV Data 011 D5 M=0GeV M =680GeV * ADD δ= M D =.5TeV Sum of backgrounds Z( νν)+jets W( lν)+jets Z( ll)+jets tt + single top Multijet Di-bosons Non collision SR1 Events/GeV 1 - Ldt = 4.7 fb s= 7 TeV SR4 Data 011 D5 M=0GeV M =680GeV * ADD δ= M D =.5TeV Sum of backgrounds Z( νν)+jets W( lν)+jets Z( ll)+jets tt + single top Di-bosons - - 00 400 600 800 00 100 500 600 700 800 900 00 10 100
EFT interpreta9on mono- jet 15 * Suppression scale M 50 40 0 0 s=7 TeV Ldt = 4.7 fb 1 Operator D1, SR, 90%CL Expected limit (± 1 exp ) Observed limit (± 1 theory ) Thermal relic WIMP mass m * Suppression scale M 100 00 800 600 400 00 s=7 TeV Ldt = 4.7 fb 1 Operator D5, SR, 90%CL Expected limit (± 1 exp ) Observed limit (± 1 theory ) Thermal relic WIMP mass m * Suppression scale M 600 500 s=7 TeV Ldt = 4.7 fb 400 00 00 0 1 Operator D11, SR4, 90%CL Expected limit (± 1 exp ) Observed limit (± 1 theory ) Thermal relic WIMP mass m * Suppression scale M 100 00 800 600 400 00 s=7 TeV Ldt = 4.7 fb Operator D8, SR, 90%CL Expected limit (± 1 exp ) Observed limit (± 1 theory ) Thermal relic 1 WIMP mass m * Suppression scale M 400 00 000 1800 1600 1400 100 00 800 600 400 00 Operator D9, SR4, 90%CL Expected limit (± 1 exp ) Observed limit (± 1 theory ) Thermal relic 1 s=7 TeV Ldt = 4.7 fb WIMP mass m M * : suppression scale M * =M med / (g SM g DM ) m χ : WIMP mass
Cross- sec9on limits mono- jet 16 ] WIMP-nucleon cross section [ cm -5-6 -7-8 -9-40 -41 SIMPLE 011 Picasso 01 D8: CDF qq j() D8: CMS qq j() 1 Dirac Dirac s = 7 TeV, 4.7 fb, 90%CL D8: qq j() Dirac D9: qq j() Dirac theory Spin-dependent WIMP mass m [ GeV ] ] WIMP-Nucleon cross section [ cm -1 - -5-7 -9-41 -9-4 -45 XENON0 01 CDMSII low-energy CoGeNT 0 D5: CDF qq j() Dirac 1 s = 7 TeV, 4.7 fb, 90%CL D1: qq j() Dirac D5: qq j() Dirac D11: gg j() Dirac theory Spin-independent WIMP mass m [ GeV ] Tighter constraint compared to Mono- γ search (D8, D9 and D5)
8 TeV measurement mono- jet s=8 TeV,.5 e - 1 - CONF- 01-147 17 8 TeV data.5 e - 1 Half of the full staasacs. Analysis follows closely the 7 TeV measurement. No excess is seen. A [pb] 1 - Preliminary Ldt=.5 fb s = 8 TeV 95% CL Expected limit Observed limit SR1 SR SR SR4 ± 1 exp ± exp [Events/GeV] T dn/de 5 data 01 Preliminary Total BG Z ( ) + jets 4 W ( l ) + jets Ldt=.5fb Multi-jet s = 8 TeV SR1 Non-collision BG Z ( ll ) + jets Dibosons tt + single top ADD n=, M = TeV (x5) D D5 M=80GeV, M =670GeV (x5) * -4 G ~ + ~ q/ ~ g, M ~ =1TeV, M ~ ~= ev (x5) q/ g G [Events/GeV] T dn/de 1 Preliminary Ldt=.5fb s = 8 TeV data 01 Total BG Z ( ) + jets W ( l ) + jets Z ( ll ) + jets Dibosons tt + single top ADD n=, M = TeV D D5 M=80GeV, M=670GeV * -4 G ~ + ~ q/ ~ g, M ev q ~ ~=1TeV, M~= /g G SR4 1 Data / BG 1.5 1 0.5 Data / BG 1.5 1 0.5 00 400 600 800 00 100 E T 400 500 600 700 800 900 00 10 100 E T
Results Expected lower limits for D5 and D8 is larger by % than 7 TeV. Expected lower limits for D11 is unchanged. * Suppression scale M 100 00 800 600 400 00 Operator D5, SR, 90%CL Expected limit (± 1 ± exp ) Observed limit (± 1 theory ) Thermal relic Preliminary s=8 TeV Ldt =.5 fb effective theory not valid mono- jet 18 WIMP mass m * Suppression scale M 1400 100 00 800 600 400 00 Operator D8, SR, 90%CL Expected limit (± 1 ± exp ) Observed limit (± 1 theory ) Thermal relic Preliminary s=8 TeV Ldt =.5 fb effective theory not valid WIMP mass m * Suppression scale M 500 Operator D11, SR, 90%CL Expected limit (± 1 ± exp ) 450 400 50 00 50 00 150 0 Observed limit (± 1 theory ) Thermal relic Preliminary s=8 TeV Ldt =.5 fb effective theory not valid WIMP mass m
MC study of sensi9vity at 14 TeV mono- jet SimulaAon only ATL- PHYS- PUB- 014-007 19 [Events/GeV] dn / d Event selecaon Simulation Preliminary - - 1 s = 14 TeV 0 500 00 1500 000 Ldt = 0 fb Z Wl top Leading jet s = 8 TeV p T >00 GeV, η <.0 s = 14 TeV > 400, 600, 800 GeV Jet definiaon p T >0 GeV, η <4.5 p T >50 GeV, η <.6 Lepton veto N jet <= Δφ(, jet) > 0.5 p T >7 GeV, η <~.5 Harder distribuaons expected at 14 TeV, more significant for signal. [Events/GeV] dn / d 1 - SM Simulation Preliminary 8 TeV, 14 TeV, Z Ldt = 0 fb Ldt = 0 fb Normalized entries - - DM Simulation Preliminary 8 TeV 14 TeV D5 m =50 GeV - -4-4 -5 0 500 00 1500 000-5 0 500 00 1500 000
Prospects with EFT approach (D5) mono- jet 0 Suppression scale M * 000 500 000 1500 00 Simulation Preliminary D5, m = 50 GeV 5% syst < g g <4 SM DM MET > 400 GeV Suppression scale M * 000 500 000 1500 00 Simulation Preliminary D5, m = 400 GeV 5% syst < g g <4 SM DM MET > 400 GeV 500 MET > 600 GeV MET > 800 GeV 0 14 TeV, 00 fb 14 TeV, 5 fb 14 TeV, 5 fb 8 TeV, 0 fb 14 TeV, 000 fb 500 MET > 600 GeV MET > 800 GeV 0 14 TeV, 00 fb 14 TeV, 5 fb 14 TeV, 5 fb 8 TeV, 0 fb 14 TeV, 000 fb Limits are expected to be improved by a factor of, with the 14 TeV data expected in the 1 st year. For m χ = 50 GeV, M * detecaon can be done up to 1.5 TeV at 5σ. (first year of data- taking.) significance [] 18 16 14 1 8 6 4 Simulation Preliminary s=14 TeV D5, m = 50 GeV < g g < 4 SM DM 5% systematic Ldt=5fb 5 discovery evidence 1 1. 1.4 1.6 1.8..4.6.8. [TeV] M *
1 Mono- γ search Mono- jet search Mono- W/Z (hadronic) search Mono- W search Mono- Z search
Mono- W/Z search mono- W/Z s=8 TeV, 0 e - 1 PRL 11 04180 (014) Strong constraint from mono- jet, due to large radiaaon rate of q and g. AssumpAon: same coupling for up- type and down- type quarks. C(u) = C(d) If DM has opposite coupling to up- type and down- type quarks C(u) = - C(d) è Interference can make Mono- W producaon be a dominant process
Analysis mono- W/Z Hadronic decay of W/Z à Reconstructed as a massive fat- jet Large- R (=fat) jet: Cambrige- Aachen jet with R=1. m jet is well described by simulaaon in top events. Narrow- jet: ana- k T jet with R=0.4 Event selecaon Large- R jet with p T >50 GeV, η <1., 50<m jet <10GeV Veto on e, μ, γ Veto on >1 narrow jet with p T >40 GeV, η <4.5 Not overlapping with large- R jet Veto if any narrow jet is close to as Δφ(, jet) < 0.4 requirements signal regions: > 50 GeV, 500 GeV
Event yields mono- W/Z 4 W/Z backgrounds esamated using control regions. No excess is observed
Results mono- W/Z 5 Senario with C(u) = - C(d) gives strong constraint. For D5 with C(u) = C(d), 7 TeV mono- jet result is slightly be9er. 8 TeV mono- W/Z gives more sensiavity than 7 TeV mono- jet for D9.
6 Mono- γ search Mono- jet search Mono- W/Z (hadronic) search Mono- W search Mono- Z search
Search with one lepton + ing Analysis is done for W search, but can be interpreted as DM search as well. Event selecaon e- channel: Electron with > 15 GeV > 15 GeV Veto on addiaonal electron with > 0 GeV μ- channel: Muon with > 45 GeV > 45 GeV Veto on addiaonal muon with > 0 GeV m T (l, ) requirement of [597, 796, 84] GeV Events Events Data/Bkg Data/Bkg 6 5 4 1 1.5 1 0.5 0 8 7 6 5 4 1 1.5 1 0.5 0 mono- W s=8 TeV, 0 e - 1 arxiv 1407.7494 accepted by JHEP Shown for m T > 5 GeV W e s = 8 TeV L dt = 0. fb W µ s = 8 TeV L dt = 0. fb Data 01 W (0.5 TeV) W (1 TeV) W ( TeV) W Z Top quark Diboson Multijet 7 Data 01 W (0.5 TeV) W (1 TeV) W ( TeV) W Z Top quark Diboson Multijet
Result mono- W 8 Be9er constraint by mono- W/Z (hadronic decay) search * M 5 4 mono-w lep, D9 mono-w lep, D5c mono-w lep, D5d mono-w lep, D1 mono-w/z had, D9 mono-w/z had, D5c mono-w/z had, D5d mono-w/z had, D1 mono-z lep, D9 mono-z lep, D5 mono-z lep, D1 D5c: construcave interference C(u) = - C(d) D5d: destrucave interference C(u) = C(d) T l + E 90% CL s = 8 TeV, Ldt = 0. fb 0 00 400 600 800 00 100 m
9 Mono- γ search Mono- jet search Mono- W/Z (hadronic) search Mono- W search Mono- Z search
Mono- Z analysis Search with leptonically decaying Z s=8 TeV, 0 e - 1 PRD 90 01004 (014) Also sensiave to direct Z- χ interacaon. dimension- 5 and - 7 operators (PRD 87, 074005) q q q Z mono- Z χ χ 0 ISR nucleon- χ Z Event selecaon A opposite- sign lepton pair (e + e - or μ + μ - ) with leptons: p T >0 GeV, η <~.5 q Z/γ χ χ direct Z- χ 76 GeV < m ll < 6 GeV (Z mass peak), η ll <.5 well balanced against Veto on rd leptons with p T > 7 GeV Veto on jets with p T > 5 GeV, η <.5 requirements 4 signal regions: > 150, 50, 50 and 450 GeV
Event yields Main backgrounds ZZ and WZ, esamated using NLO MCs. No excess is seen Entries / 50 GeV Data/MC 8 mono- Z 7 Data WZ W/Z+jets ZZll 6 WW/Top quark Systematic Unc. 5 D1, M =0.050 TeV * ZZ max., M =0.7 TeV * 4 Mediator, m =1 TeV, f=6 L=0. fb s=8 TeV m =00 GeV 1-1.4 1. 0.8 1 0.6 0 50 0 150 00 50 00 50 400 450 500 1
EFT interpreta9on Nucleon- χ: D1, D5 and D9 Z- χ: dimension- 5: ZZχχ dimension- 7: ZZχχ with maximum / negligible Zγ* contribuaon M * 4 L=0. fb s=8 TeV 90% C.L. D1 D5 D9 ZZ ZZ max. ZZ no 0 00 400 600 800 00 m mono- Z ] -nucleon cross section [cm -1 - - -4-5 -6-7 -8-9 -40-41 -4-4 L=0. fb s=8 TeV 90% C.L. 1 D9 D9 8 TeV W/Z had.( ) D9 7 TeV jet( ) COUPP 01 SIMPLE 011 Picasso 01 + IceCube W W - IceCube b b spin dependent m ] -nucleon cross section [cm -0-1 - - -4-5 -6-7 -8-9 -40-41 -4-4 -44-45 -46 L=0. fb s=8 TeV 90% C.L. 1 D1 D5 D5 8 TeV W/Z had.( ) D1 7 TeV jet( ) D5 7 TeV jet( ) CoGeNT 0 CDMS 014 XENON0 01 LUX 014 spin independent m
Interpreta9on with simplified model mono- Z Assume scalar t- channel mediator η, with η- χ coupling strength f. Color triplet, EW doublet, Y W =1/ m 100 10 00 900 800 700 600 500 400 00 00 L=0. fb s=8 TeV 0 00 00 400 500 600 700 800 900 00 m 1 8 6 4 0 95% C.L. on coupling f
Summary: Latest Results Mono- jet @ 7 TeV ] -N cross-section [cm Mono- W/Z (hadronic) @ 8 TeV Mono- W @ 8 TeV Mono- Z @ 8 TeV ] -N cross-section [cm - -4-5 -6-7 -8-9 -40-41 -4-4 -4-5 -6-7 -8-9 -40-41 -4-4 -44-45 -46-47 90% CL 0. fb s = 8 TeV mono-w lep, D9 mono-w/z had, D9 mono-jet 7 TeV, D9 mono-z lep, D9 spin-dependent 1 mono-w lep, D5c mono-w lep, D5d mono-z lep, D5 90% CL LUX 014 CoGeNT 0 XENON0 01 SuperCDMS 014 mono-jet 7 TeV, D5 1 PICASSO 01 SIMPLE 011 + - IceCube W W IceCube bb COUPP 01 0. fb s = 8 TeV m spin-independent m mono-w/z had, D5c mono-w/z had, D5d 4
Summary 5 If Dark Ma9er couples Standard Model paracles, DM can be produced at colliders. Search of WIMP pair producaon, with iniaal state radiaaon of energeac object: Mono- X + large has performed several Mono- X searches. 7 TeV data (5 e - 1 ) : X= photon, jet 8 TeV data (0 e - 1 ) : X= W/Z(- >qq), W(- >lν), Z(- >ll) Good agreement is seen between data and SM predicaons. Limits are set on EffecAve Field Theory The coming 1/14 TeV runs are expected to give be9er sensiavity in DM searches.
Backup 6
EFT operators 7 from J. Goodman et. al., PRD 8, 1160 (0)
Upgrade study: EFT validity 8 Validity of EFT requires Q Tr < M * (g SM g DM ) Q Tr : interacaon scale R tot Mmed FracAon of valid events [%] tot R Mmed 0 80 60 40 0 0 Simulation Preliminary s 1 m = 8 TeV - = 50 GeV L = 0 fb > 400 GeV > 600 GeV > 800 GeV 1 1.5.5 g g SM DM [%] tot R Mmed 0 80 60 40 0 0 Simulation Preliminary s 1 m = 14 TeV - = 50 GeV L = 5 fb > 400 GeV > 600 GeV > 800 GeV 1 1.5.5 g g SM DM [%] tot R Mmed 0 80 Simulation Preliminary [%] tot R Mmed 0 80 Simulation Preliminary 60 60 40 0 0 s 1 m = 8 TeV - = 400 GeV L = 0 fb > 400 GeV > 600 GeV > 800 GeV 1 1.5.5 g g SM DM 40 0 0 s 1 m = 14 TeV - = 400 GeV L = 5 fb > 400 GeV > 600 GeV > 800 GeV 1 1.5.5 g g SM DM
8 TeV mono- jet event yields 9