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Dark Matter at the LHC

Dark Matter at the LHC. Bhaskar Dutta Texas A&M University. Texas Cosmology Network Meeting, UT, Austin. 30 th Oct ’ 09. Dark Matter at the LHC. 1. Dark Matter and SUSY. + …. We need to observe the new layer of matter in order to establish this explanation. Dark Matter at the LHC.

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Dark Matter at the LHC

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  1. Dark Matter at the LHC Bhaskar Dutta Texas A&M University Texas Cosmology Network Meeting, UT, Austin 30th Oct ’ 09 Dark Matter at the LHC Cosmological Connection at the LHC: Stau Neutralino Coannihilation Case 1

  2. Dark Matter and SUSY + …. We need to observe the new layer of matter in order to establish this explanation Dark Matter at the LHC 2

  3. SUSY at the LHC (or l+l-, t+t-) High PT jet [mass difference is large] DM The pT of jets and leptons depend on the sparticle masses which are given by models Colored particles get produced and decay into weakly interacting stable particles DM R-parity conserving (or l+l-, t+t-) High PT jet The signal : jets + leptons + missing ET Dark Matter at the LHC 3

  4. SUSY Models 4 parameters + 1 sign Minimal Supersymmetry Standard Model has more than 100 parameters • We may not have enough observables to establish them • We start with a simple scenario and go to complicated cases mSUGRA: Minimal Scenario Dark Matter at the LHC 4 4

  5. Dark Matter Allowed Regions tanb= 40 A0 = 0, m > 0 FP/HB Region 3 c m0 (GeV) Over-dense DM Region 2 a b m1/2 (GeV) Coannihilation Region 1 • Excluded by • Rare B decay bsg • No CDM candidate • Muon magnetic moment a b c Dark Matter at the LHC 5 5

  6. Observables at the LHC Mjtt &Mjt ETjet > 100 GeV SUSY Masses pTt> 40 GeV 97% 100% Mtt & pT(t) pTt> 20 GeV (CDM) The observables include: Z, h, W, t, t, b, jet, l and missing energy The observables are determined by the underlying physics of the model Dark Matter at the LHC

  7. Case1. Coannihilation Region Griest, Seckel ’91 + …. Low energy taus characterize the CA region However, one needs to measure the model parameters to predict the dark matter content in this scenario SUSY Masses 97% 100% (CDM) 2 quarks+2 t’s +missing energy Arnowitt, Dutta, Kamon,Toback’08 7 Dark Matter at the LHC

  8. Determining mSUGRA Parameters • Solved by inverting the following functions: 10 fb-1 Dark Matter at the LHC 8 8 Phys.Rev.Lett.100:231802,2008.

  9. Case 2 : Over-dense region m1/2=440, m0=471, tanb=40, mtop=175 1041 1044 500 393 341 462 87% 181 114 ETmiss > 180 GeV; N(jet) > 2 with ET > 200 GeV; ETmiss + ETj1 + ETj2 > 600 GeV N(b) > 2 with PT > 100 GeV; 0.4< DRbb < 1 13% 91 Dark Matter at the LHC 9 9

  10. DeterminingWh2 • Solved by inverting the following functions: 1000 fb-1 Dutta, Kamon,Nanopoulos etal ’09 Phys.Rev.D79:055002,2009 Dark Matter at the LHC 10 10

  11. Case 3 : Focus Point /HB Z m0, A0, m, tanb Prospects at the LHC: A few mass measurements are available: 2nd and 3rd neutralinos, and gluino Z Z Z m1/2, m, tanb M4x4 (m1/2, m, tanb ) Dark Matter at the LHC 11 11

  12. Case 4 : Non-U SUGRA Nature may not be so kind …Our studies have been done based on a minimal scenario (= mSUGRA). … Let’s consider a non-universal scenario: Higgs non-universality: mHu, mHd m0 • Steps: • Reduce Higgs coupling parameter, m, by increasing • mHu, …  More annihilation (less abundance) •  correct values of Wh2 • 3) Find smoking gun signals  Technique to calculate Wh2 SUGRA Models at the LHC 12 12

  13. Extraction of Model Parameters Dark Matter at the LHC 13

  14. End-points-nonuniversal We have 3 (4) parameters in the chargino-neutralino system: m1/2, m, tanb (m1,m2, m, tanb) M(jW) [ ] = 714.6 GeV M(jW) [ ] = 727.3 GeV [use 2 t’s since ] M(jW)[ ] = 652.4 GeV [use Z since ] M(jW) [ ] = 738.6 GeV We can use stop decay chain In this case we use a b/t ~500 GeV M(bW) Theory:738.8 Similarly, M(tZ) =338 GeV M(jW) Mttt, Mjtt etc can also be constructed Dark Matter at the LHC

  15. Conclusion Signature contains missing energy (R parity conserving) many jets and leptons : Discovering SUSY should not be a problem! Once SUSY is discovered, attempts will be made to measure the sparticle masses (highly non trivial!), establish the model and make connection between particle physics and cosmology Different cosmologically motivated regions of the minimal model have distinct signatures. It is possible to determine model parameters and the relic density based on the LHC measurements Work is in progress to determine non-universal model Parameters----looks promising Dark Matter at the LHC

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