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SUSY with Photons and MET: Introduction and thoughts about Diphoton and Single Photon Analyses

SUSY with Photons and MET: Introduction and thoughts about Diphoton and Single Photon Analyses. Annecy DESY/University of Hamburg Liverpool University Tokyo Tech University of California Santa Cruz Universidad Nacional de La Plata University of Wisconsin Weizmann Institute. General Intro.

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SUSY with Photons and MET: Introduction and thoughts about Diphoton and Single Photon Analyses

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  1. SUSY with Photons and MET: Introduction and thoughts about Diphoton and Single Photon Analyses Annecy DESY/University of Hamburg Liverpool University Tokyo Tech University of California Santa Cruz Universidad Nacional de La Plata University of Wisconsin Weizmann Institute

  2. General Intro

  3. Photon processes in SUSY Collider phenomenology depends on nature of LSPs mSUGRA GMSB LSP: gravitino ( massless) NLSP: lightest neutralino production: tree level • LSP: lightest neutralino • NLSP: 2nd neutralino • production: 1-loop Signature:  + MET (+ X) This group’s focus so far

  4. What is the X in “(+X)”? • This depends on the composition of the NLSP 0: • 0 = Bino  B(0  G) ≈ 80%  X = 2nd • 0 = [Bino  Wino]  X = lepton (Jovan) • 0 = [Bino  Higgsino]  X = b-jet(s) (Ofir) • 0 = [Bino  ???]  X = as little as possible (CMS: 3 jets with 30 GeV ET. • Other notes: • If Mcolored ≈ M0, additional activity can be very limited • If G (gravitino) coupling is weak, 0 can be metastable (non-pointing photons!) (Helen)

  5. Diphoton Analysis

  6. Basic Selection: • 2 with PT > 25 GeV • MET > 125 GeV

  7. Limits: Cast in 2D space of Mcolored vs MBino

  8. N.B. Comparison with CMS • In terms of the observed cross section limit, CMS and ATLAS are essentially identical (~25 fb-1), and: • These can be directly compared (same syst. error content) • P(e)CMS ≈ 0.1*P(e )ATLAS • CMS used slightly (~6%) more luminosity • CMS got slightly lucky (expected 1.5; observed 0) • Despite appearances (mass limit), ATLAS analysis appears superior per fb-1 In addition, ATLAS did not optimize for 1 fb-1 (we used essentially the same analysis as for 0.036 fb-1) We need to optimize; should result in favorable analysis relative to CMS

  9. Diphoton Analysis: Next Steps • First things first: we need to explore (clean up?) MET variables for events with high PT photons. From Jason: • Not all of our recovered photons are treated correctly by the MET reconstruction, and we have some anecdotal evidence from our high-MET candidates that this is worse in high-pT photon events. Probably this is because of the straight scaling EM->hadronic JES; this makes the size of the (wrongly applied) correction larger for the high-pT photons. • This will have to be explored at AOD stage and brought forward (officially) into the D3PDs

  10. Diphoton Analysis

  11. Diphoton Analysis

  12. Diphoton Analysis

  13. Diphoton Analysis

  14. SUSY  single photon + MET + X University of California Santa Cruz Universidad Nacional de La Plata

  15. via gravity (mSUGRA) via gauge mediation (GMSB) At low energies, most scenarios with similar spectra… SUSY Broken in nature (mSUGRA) (GMSB) …but possible different phenomenologies at colliders.

  16. Experimental Signature Trigger: • EF_g40_loose_xe45_medium_noMu/EF_g40_loose_xe55_medium_noMu triggers? • g80_loose g100_loose (5. 1033 ) ? Selection: - |η| range, Photon pT , Photon quality :Tight?, Etcone (Calo isolation) vs Ptcone (track isolation)? MET definition, i.e. MET_RefFinal? ( Currently use LocHadTopo) number of Jets? Efficiencies: - Follow photon efficiency task force! - MET: Bruce please add….. Background: data driven methods • QCD: Prompt photon (direct / fragmentation) follow SM analysis • W, Z ttbar…

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