1 / 14

SUSY @ Atlas

SUSY @ Atlas. S.Sushkov IFAE seminar 2005-12-20. Intro: SUSY basics (1). new symmetry: SUSY partners for each SM particles MSSM: minimal SUSY based on SM 124 arbitrary parameters 2 Higgs doublets  5 Higgs particles: h 0 , H 0 , A 0 , H . Intro: SUSY basics (2).

ull
Download Presentation

SUSY @ Atlas

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SUSY @ Atlas S.Sushkov IFAE seminar 2005-12-20

  2. Intro: SUSY basics (1) • new symmetry: SUSY partners for each SM particles • MSSM: minimal SUSY based on SM • 124 arbitrary parameters • 2 Higgs doublets  5 Higgs particles: h0, H0, A0, H

  3. Intro: SUSY basics (2) SUSY breaking: MSM ≠ MSUSY • SUGRA: gravity-mediated • SUSY breaking scale ~ 1011 GeV • sparticle masses ~ EW < 1 TeV • C-MSSM (constrained): M2, m0, A0, tan β, , MA • & GUT unification  mSUGRA: • m1/2 = GUT-unified gaugino mass • m0 = GUT-unified scalar mass • A0 = universal trilinear coupling • tan β = ration of higgs VEVs @ EW scale • sign() = sign of higgsino mass par. @ EW scale • GMSB: gauge-mediated • SUSY breaking scale ~ 106 GeV • LSP = Gravitino (~ eV-keV) • different phenomenology

  4. Intro: SUSY basics (3) R-parity: SM=+1, SUSY=-1 R = (-1)2S + 3(B-L) • Conserved R-parity: • sparticles produced/disappear in pairs • stable & “invisible” (weak int.) LSP = ETmiss • candidate for CDM • R-parity Violation (SUGRA): • single sparticle production / decay • no stable LSP  no (high) ETmiss • possible B- / L- violation • ijk , ’ijk , ”ijk& additional 45 params.

  5. SUSY search points (1) • Scan whole multidim. • parameter space • impossible • choose / check typical points in param. space

  6. SUSY search points (2) - SUGRA All typical combinations of mSUGRA parameters

  7. Signatures by model • SUGRA • R-parity conserved:high ETmiss + N1jets + N2leptons • small squark/sgluino masses: direct decays • high squark/sgluino masses: cascade decays • R-parity violationjets, leptons & NO ETmiss • lepton-number violation • baryon-number violation • GMSB (R-parity conserved)ETmiss& photons

  8. Goal 1: discovery excess of typical SUSY quantity over SM: Meff = Σ4max PTj + ETmiss Meff(GeV) • “Atlas” variable Sf = Sig /  BG • “CMS” variable Sf = Sig /  (Sig+BG) • “Combined” variable Sf =  (Sig+BG) -  BG Ath. 10.0.4 updated generator TDR

  9. Goal 2: measurements Difficulty:two unknown sparticles in each decay kinematic edges techniques to constraint masses: • locate region of data excess over SM, estimate branchings • try to constrain kinematics & parameters • derive masses or their ratios T.Lari, “SUSY studies with Atlas: hadr. sign. and focus point” Example: lepton pair at SPS3

  10. SUSY@Atlas: Working Group Convenors: Dan Tovey, Shoji Asai (Frank Paige) WG web home:http://paige.home.cern.ch/paige/susy/susy.html Participating Institutes (main): • Bern, CERN, Columbia U. • Brookhaven, Berkeley • Cambridge, Oxford • INFN, NIKHEF • Marseille, Stockholm • (several more)

  11. SUSY@Atlas: crucial issues Main activities of SUSY WG • Calorimetry & jet energy • reconstruction methods (cone / Kt) • understand det. performance & calibr. • ID for analysis: quark/gluon jets • Missing ET: Calo hermeticy • QCD BG MC: NLO vs. LO correct. (CDF/D0 experience) • Reconstruction & ID algorithms • fake object ID • good b-tagging • Trigger algorithms • efficiency / performance tuning • SUSY: techniques of param. determination

  12. SUSY@Atlas: crucial issues Example: Calo hermeticy forETmiss  (∆E/E) EJET, GeV

  13. SUSY@Atlas: future tasks (see hep-ph/0202233)

  14. Conclusions • Atlas SUSY WG: • Main modelS investigated • Techniques evolving: • Reco & id • Parameters determination • SM/QCD BG MC preparing • Good det. performance/calibr. needed • IFAE: • lots of areas to join (example: taus) • good chance to cooperate with TileCal • Det. performance & calibr. • Jets reco & cross-section

More Related