Tevatron Constraintspp→ jets + missing energyGoodman,Ibe,Rajaraman,Shepherd,Tait,Yu(1005.1286,1008.1783);Bai,Fox,Harnik(1005.3797)StudythepropertiesofAaltonenetal.[cDFCollaborationlPRL101,181602,2008.largeextradimensionmodelsLeading jet E >80 GeV;Pr of second jet < 30 GeV;Vetoing anythirdjet with E>20 GeV;Missing E_ > 80 GeV.1fb-1ofdatafromTevatron,8449eventsobserved.SMbackground8663±332;Onew < 0.664 pbHard processis good enough
Tevatron Constraints ◼ Leading jet ET > 80 GeV; ◼ pT of second jet < 30 GeV; ◼ Vetoing any third jet with ET > 20 GeV; ◼ Missing ET > 80 GeV. ◼ 1 fb-1 of data from Tevatron, 8449 events observed. ◼ SM background 8663±332; ◼ Hard process is good enough. Goodman, Ibe, Rajaraman, Shepherd, Tait, Yu (1005.1286, 1008.1783); Bai, Fox, Harnik (1005.3797). Aaltonen et al. [CDF Collaboration], PRL 101, 181602, 2008. Study the properties of large extra dimension models
Contact OperatorIn the work by Irvine group, effective four particle interactionis usedto studytheTevatronconstraintand LHC predictionHowever,in Tevatronthe center-of-mass energy of the proton-anti-proton pair is 1.96 TeV, therefore if the mass of the intermediateparticle is around a few hundred GeV, the interaction cannot beconsideredasacontactinteraction.Furthermore,ifthe result of CoGeNTis inducedbyelasticSl,Mlcollision between dark matter and nuclei, the effective coupling canbe written as19SM9DM23)TeVmediator
Contact Operator ◼ In the work by Irvine group, effective four particle interaction is used to study the Tevatron constraint and LHC prediction. ◼ However, in Tevatron the center-of-mass energy of the proton-antiproton pair is 1.96 TeV, therefore if the mass of the intermediate particle is around a few hundred GeV, the interaction cannot be considered as a contact interaction. ◼ Furthermore, if the result of CoGeNT is induced by elastic SI, MI collision between dark matter and nuclei, the effective coupling can be written as
Z-boson mediatorMDM<<MzCoupling between Mz and DM should be smaller than 0.02.Relicabundanceistoolarge
Z-boson mediator ◼ MDM << MZ . ◼ Coupling between MZ and DM should be smaller than 0.02. ◼ Relic abundance is too large
Standard Model HiggsIf dark matterisa fermion, sincethe Yukawa couplingsto lightquarks are small. The relic abundance is too large.However.ifdarkmatterisascalar.therelicabundanceconstraintcanbeavoided.(Xiao-gang'stalk)(a)SM3+D300GeV200GeV0.1115GeV0.010.001510501005001000mp (GeV)
Standard Model Higgs ◼ If dark matter is a fermion, since the Yukawa couplings to light quarks are small. The relic abundance is too large. ◼ However, if dark matter is a scalar, the relic abundance constraint can be avoided. (Xiao-gang’s talk)
Possible InteractionsSMHiggs+Scalardarkmatterisstill possibleDark matter: Complex Scalar (), Dirac Fermion (x)Mediator: Scalar (H), Vector (Z)T-channel annihilation, colored particle. (Will be study elsewhere)Morecomplicatedcases
Possible Interactions ◼ SM Higgs + Scalar dark matter is still possible. ◼ Dark matter: Complex Scalar (Φ), Dirac Fermion (χ). ◼ Mediator: Scalar (H’), Vector (Z’). ◼ T-channel annihilation, colored particle. (Will be study elsewhere). ◼ More complicated cases