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Dark Matter at Colliders Bhaskar Dutta Texas A M University 06 15 11 PPC 2011 1 Discovery Time We are about to enter into an era of major discovery Dark Matter we need new particles to explain the content of the universe Standard Model we need new physics Supersymmetry solves both problems The super partners are distributed around 100 GeV to a few TeV LHC directly probes TeV scale Future results from PLANCK direct and indirect detection rare decays etc experiments in tandem with the LHC will confirm a model This talk Can we establish SUSY models at the LHC How accurately we can calculate dark matter density 2 SUSY at the LHC Wang s talk morning or l l t t High PT jet mass difference is large DM Colored particles are produced and they decay finally into the weakly interacting stable particle High PT jet The pT of jets and leptons depend on the sparticle masses which are given by models DM R parity conserving or l l t t The signal jets leptons t s W s Z s H s missing ET 3 SUSY at the LHC Dilemma 4 SUSY at the LHC Dilemma 5 SUSY at the LHC Final states Model Parameters Calculate dark matter density Reconstruct sparticle masses e g 0 Q q l 1 0 L l Identifying one side is very tricky 1 0 2 3 4 0 Z h l l 1 etc We may not be able to solve for masses of all the sparticles from a model Solving for the MSSM Very difficult 6 SUSY at the LHC We can use simpler models to understand the cascades and solve for the model parameters Calculate the Dark Matter content The best strategy Solve for the minimal model mSUGRA CMSSM 4 parameters sign m0 m1 2 A0 tanb and Sign m The cascades can be understood in a simpler way hopefully Next step Models with more parameters e g Next to minimal model Higgs non universality Gaugino Non universality Mirage Mediation model etc 7 mSUGRA Parameter space Focus point Allahverdi Dutta Santoso PLB 687 225 2010 Coannihilation Region The bounds from CDMS Xenon 100 have started becoming competitive with b s g and Higgs mass constraints warning Nuclear Matrix element etc 8 1 Coannihilation GUT Scale In mSUGRA model the lightest stau seems to be naturally close to the lightest neutralino mass especially for large tanb For example the lightest selectron mass is related to the lightest neutralino mass in terms of GUT scale parameters 2 m 2 0 15m 2 37 GeV 2 m m 2 0 16m 2 0 1 2 1 2 Ec 10 2 0 E Thus for m0 0 1 at m1 2 370 GeV c becomes degenerate with i e the coannihilation region begins at Arnowitt Dutta Santoso 01 m1 2 370 400 GeV For larger m1 2 the degeneracy is maintained by increasing m0 and we get a corridor in the m0 m1 2 plane The coannihilation channel occurs in most SUGRA models even with nonuniversal soft breaking 9 Smoking Gun of CA Region Typical decay chain and final states at the LHC g u SUSY Masses u L Jets t s missing energy Low energy taus characterize the CA region 20 0 1 u t t1 CDM t However one needs to measure the model parameters to predict the dark matter content in this scenario 2 quarks 2 t s missing energy 10 CA Region Final States SUSY Masses g u u L Mjtt Mjt 20 0 1 Example of Analysis Chart for b u t t 1 CDM Excesses in 3 Final States a ETmiss 4j Kinematical miss b ET 2j 2t variables miss c ET b 3j t Mtt pT t t 50 ffake 1 for pTvis 20 GeV 11 SUSY at the LHC Dilemma 12 SUSY at the LHC Dilemma OS LS Subtraction 13 Extracting One side jtt OS LS selection of ditaus selects the entire side 0 2 but if we need to reconstruct We use the following subtraction scheme 2t Bi Event Subtraction technique BEST 14 BEST and SUSY Dilemma 15 BEST Dutta Kamon Kolev Krislock arXiv 1104 2508 hep ph 16 What BEST Looks Like 17 Top reconstruction BEST 18 End Point Techniques with BEST Significance improves 5 times with BEST 19 DM Relic Density in mSUGRA 1 Established the CA region by detecting low energy t s pTvis 20 GeV 2 Measured 5 SUSY 0 0 q g from DM 1 2 M peak X 1 m1 2 m0 jtt M ttpeak X 2 m1 2 m0 tan b A0 peak M eff X 3 m1 2 m0 peak M eff b X 4 m1 2 m0 tan b A0 masses 3 Determine the dark matter relic density by determining m0 m1 2 tanb and A0 0 h2 Z m0 m1 2 tan b A0 1 20 Determining mSUGRA Parameters Solved by inverting the following functions M peak jt t X 1 m1 2 m0 Mtpeak t X 2 m1 2 m0 tan b A0 M M peak eff b peak eff m0 X 3 m1 2 m0 10 210 5 m1 2 350 4 fb 1 A0 0 16 tan b 40 1 X 4 m1 2 m0 tan b A0 0 h2 Z m0 m1 2 tan b A0 1 50 fb 1 L 10 fb 1 h2 h2 6 2 30 fb 1 0 1 0 1 p 0 1 0 p 7 30 fb 1 1 4 1 70 fb 1 21 Comparison ILC analysis 500 GeV m0 210 m1 2 350 A0 0 tan b 40 DM 9 5 1 1 1 0 500 LHC fb 1 We need 50fb 1 Arnowitt Dutta Kamon PLB 05 We can determine DM at the LHC This result was used in Baltz Battaglia Peskin Wizansky 05 to extract relic density by using ILC and LHC LCC3 point 05 Arnowitt Dutta Kamon et al PRL 08 22 GUT Scale Symmetry We can probe the physics at the Grand unified theory GUT scale g mass m1 2 Use the masses measured at the LHC and evolve them to the GUT scale using mSUGRA 20 10 MZ Log Q MGUT The masses 10 20 g unify at the grand unified scale in the mSUGRA model Gaugino universality test at 15 10 fb 1 Another evidence of a symmetry at the grand unifying scale Mirage mediation models can be discerned 23 2 Over dense DM Region m0 A0 0 tanb 40 Dilaton effect creates new parameter space m1 2 Lahanas Mavromatos Nanopoulos PLB649 83 90 2007 Smoking gun signals in the region 24 2 Reference Points m1 2 440 GeV m0 471 GeV 86 8 m1 2 600 GeV m0 440 GeV 77 0 25 Case 2 a Higgs m1 2 440 m0 471 tanb 40 mtop 175 g u L 1041 u e R 500 t 0 2 181 1 1 393 341 0 1 1044 h 114 ETmiss 180 GeV N jet 2 with ET 200 GeV ETmiss ETj1 ETj2 600 GeV 462 Z N b 2 with PT 100 GeV 0 4 DRbb 1 91 …


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