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Supersymmetry in the light of LHC experiments

Supersymmetry in the light of LHC experiments. Free Meson 7 th April, 2011. Outline. Supersymmtery searches : Results from CMS and ATLAS Discovery potential Constraints on SUSY Implications of those constraints on SUSY models.

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Supersymmetry in the light of LHC experiments

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  1. Supersymmetry in the light of LHCexperiments Free Meson 7th April, 2011

  2. Outline • Supersymmtery searches : Results from • CMS and ATLAS • Discovery potential • Constraints on SUSY • Implications of those constraints on SUSY models

  3. The Minimal Supersymmetric Standard model(MSSM) Supersymmetry : particles + sparticles 2 Higgs doublets, coulping mu, ratio of vevs , tanbeta SUSY is not an exact symmetry, has to be broken. Presence of soft terms makes larger set of free parameters(100+) Often assume universality, single m0, single m1/2, single A0, B0 universality assumes at the GUT scale. cMSSM/mSUGRa NUHM1…

  4. The MSSM: particle content Couplings are parameter space dependent

  5. SUSY: Signal and Backgrounds Generic signal:

  6. Production Cross Sections • SUSY-discovery challenge • total event rate dominated by huge QCD cross section • reject SM by many orders of magnitude ! • understand SM events that survive SUSY selection • Tevatron  LHC • σSUSY increases 20000(!) for mgluino= 400 GeV • S/B improves • Tevatron  LHC • σSUSY increases 20000 for mgluino=400 GeV • S/B improves

  7. SUSY searches at the LHC Photons + jets +MET

  8. Jets + MET : CMS For Dijet system ̴ 0.5, very useful in suppressing the backgrounds. HT ≥ 350 GeV

  9. Jets + MET: CMS For multijet system: No. of jets ≥ 3

  10. Jets + CMS

  11. Jets + CMS 13 events are observed in the data consistent with SM prediction; also the Kinematic properties are consistent with the backgrounds

  12. Jets + CMS Squark ̴ Gluino mass ≥ 650 GeV excluded.

  13. Jets+MET: ATLAS ATLAS 1102.5290 Mass of gluino below ̴ 775 GeV are excluded

  14. Lepton + jets + MET: ATLAS ATLAS: 1102.2357 • Electron or muons with pt>20 GeV and |eta|< 2.4 • 3 jets with pt>60,30,30 GeV • phi(jets,met)>0.2, and MT>100 GeV • MET >0.25 MEFF, with Meff > 500 GeV • Background events are estimated from data 2.2(2.5) events are observed in the electron(muon) channel @95%C.L. 0.065 pb (0.073)pb in the elctron(muon channel

  15. Lepton+jets+MET: ATLAS Gluino mass >700 GeV excluded

  16. Lepton+jets+MET:CMS and ATLAS

  17. Dilepton(OS/SS) + jets +MET:CMS Two leptons with at leat one lepton Pt>20 GeV and other lepton Pt>10 GeV 3 jets with PT>30 GeV, |eta|<2.4 MET>50 GeV and HT>100 Gev Background estimation is from data. More cleaning cuts In the data with one event is observed.

  18. Dilepton + jets +MET:CMS

  19. Dilepton+jets+MET:CMS SS OS Gluino mass > 600 GeV excluded

  20. Dilepton + JETS + MET:ATLAS Squark masses ̴ 450- 600 is excluded

  21. SUSY searches at LHC 2010 Data with L=35/pb

  22. Discovery Potential at 7 TeV(L=1/fb) X. Tata et. al. 1004.3594 Gluino mass upto ̴ 1 TeV can be explored with L=1/fb

  23. Discovery Potential at 7 TeV(L=1/fb) MG, DipanSengupta. 1102.4785 TranseverseThurst T<0.9 kills good fraction of QCD background

  24. Discovery Potential at 7 TeV(L=1/fb) MG, DipanSenputa. 1102.4785 RT < 0.85 suppress backgrounds significantly Backgrounds: top, QCD, W/Z+jets, tbW+jetsttw+jets, WW,WZ,ZZ+jets Significance is signal rate limited Conservative estimates gluino mass ̴1.1 TeV can be probed for L=1/fb

  25. Constraints on SUSY

  26. Effect of new B->tau+nu data Bhattacharjee, Dighe,Ghosh,Raychaudhuri,1012,1052 Is large non-SM contribution to B->tau+nu supported by K->mu+nu data? M. Montonelli, et.al 1005.2323

  27. Constraints and Model P.Nath et. al. 1103.1197 Exclusions limits are parameter space sensitive, mainly the leptonic final states ATLAS results on lepton and 0 lepton search are used. Observed Ne<2.2, Nmu < 2.5 events. Used same type cuts a la ATLAS. A0 tanbeta 0 3 0 45 2 m0 45 1 lepton channel

  28. Exclusion m0-m1/2 Largest number of single lepton channel arise at low mass scales, decrease for higher Values; ATLAS constraints do not rule out any a low mass gluino ̴ 400 GeV, for heavy squark mass

  29. Exclusion m0-m1/2 WMAP removes 96.5% alone Flav + Collider elimininates 12%

  30. Exclusion m0-m1/2 Flav+Collider+WMAP Green region is still un explored. Confirms light gluino mass still alowed. Confirms CMS and ATLAS limits are consistents

  31. What if the LHC does not find SUSY at 7 TeV run? K. Desch et .al 1102.4693 • Rare decays of B and K mesons • anomalous magnetic moment of muon • EW precision observables LEP, SLC and Tevatron • Higgs boson mass limits(HiggsBounds) • Dark Matter • ATLAS jets + MET + 0 lepton results Used Fittino

  32. Contd.. No LHC results + LHC results M0=75(+115-29), m1/2 = 329(+92-83) Tanbeta = 13(+10-7); A0 = 417(+715-725) M0=270(+423-143), m1/2 = 655(+150-81) Tanbeta = 32(+18-21); A0 = 763(+1238-879)

  33. Contd.. Mass spectrum for Best fit values Glunio and squark masses are above TeV scale.

  34. Contd.. Squark_R mass ̴ TeV Slepton_R mass ̴ 300-500 GeV NO SIGNAL from LHC at 1/fb will push the masses to higher scales.

  35. Predictions from the LHC O.Buchmuller, Ellis et.al 1102.4585 Global SUSY Fits • Precision EW data • Higgs mass limits(HiggsBounds) • Dark Matter • B decay(s+gamma, mu^+mu^-) • Muon anomalous magnetic moment • Analyze various variation of models. Frequentist approach(MasterCode)

  36. Contd… No significant reductions in fit probalities No significant tension or conflict

  37. Contd.. Fitted Gluino mass mSUGRA CMSSM Best fit values migrate to higher masses

  38. Contd.. No Higgs limits used CMS and ATLAS constraints are consistent with LEP direct bounds.

  39. Conclusion • CMS and ATLAS predict better bounds on gluinos and • squarks masses, still, light gluino mass is allowed for • heavy squark mass. • In CMSSM, the CMS and ATLAS has confirm the prediction from • indirect constraints. • Global Fitted spectrum shows gluino and squark masses are of • the ̴ TeV scale. Expect to see signal at 7 TeV LHC with 1/fb. • If not?

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