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Light higgs decay in SUSY cascade

Light higgs decay in SUSY cascade. Introduction Trigger efficiency B tagging Jet energy resolution Invariant mass reconstruction Endpoints Conclusion . Alain Romeyer (Mons - Belgium). Introduction. Benchmark point LM5 Tan b = 10 A O = 0 µ > 0 M 1/2 = 360 GeV M 0 = 230 GeV.

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Light higgs decay in SUSY cascade

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  1. Light higgs decay in SUSY cascade • Introduction • Trigger efficiency • B tagging • Jet energy resolution • Invariant mass reconstruction • Endpoints • Conclusion Alain Romeyer (Mons - Belgium) Alain Romeyer - January 2005

  2. Introduction Benchmark point LM5 Tan b = 10 AO = 0 µ > 0 M1/2 = 360 GeV M0 = 230 GeV MSUGRA 5 parameters : m0, m1/2,A, tan b, sign(µ) S. Abdullin – L. Pape Update II of the new MSUGRA test points proposal Alain Romeyer - January 2005

  3. LSP MET p q q b B tagging b … p Same decay chain may appears on the other side… Alain Romeyer - January 2005

  4. Simulated events • Production of signal events and pile-up • Signal events : all SUSY channel (easier for later event reweighting) • ~20% contains our decay chain • Digitisation : merge pile-up and signal • official 100 000 evts production at CERNavailable • our reconstruction strategy launched on digis Isajet 7.69 + Pythia 6220 + CMKIN generator FULL SIMULATION CHAIN simulation OSCAR digitisation ORCA8_7_4 Alain Romeyer - January 2005

  5. « Reconstruction » strategy • ORCA Reconstruction Simulatedevents • II - Jet Reconstruction : • Iterative Cone Algo. • cone size : 0.5 • tower Et thr. : 0.5 GeV • seed Et thr. : 1 GeV I – L1 +HLT Efficiency ? Jet sel. Pt > 30 GeV • III - B tagging : • Combined B Tagging • S > 1.5 • Analysis • event selection • IV - b ̅b inv mass reco. • MET : • MET from EcalHcalTower Alain Romeyer - January 2005

  6. C++ code in ORCA • Chi2chi1hbbAnalysis • Several .cc and .h files for each reconstruction module (MET, Trigger, Jets, Btagging, ROOT …) • Stored in CVS on ppemons (http://cms.umh.ac.be) : • setenv CVSROOT :pserver:note@ppemons.umh.ac.be:/var/www/html/cvsweb/cvs • cvs login -> password is n0te • Cvs co Chi2Chi1hbbAnalysis • Scram b • RunAnalysis –c orcarc_example • Produce root files for analyses (MC info + Reco objects) Alain Romeyer - January 2005

  7. Trigger efficiency • L1 : 99.9 % - HLT : 96 % Low Lumi. Non cumulative Trigger !!! ~ all events !!! Caveat : ~ same efficiency for SUSY bkg. Alain Romeyer - January 2005

  8. Btagging Nhiggs = Nhiggs after HLT * ( Btag Eff. )² ~ 4700 evts Alain Romeyer - January 2005

  9. Jet energy resolution Alain Romeyer - January 2005

  10. Njets Alain Romeyer - January 2005

  11. MET Alain Romeyer - January 2005

  12. dRbb Alain Romeyer - January 2005

  13. Minv Alain Romeyer - January 2005

  14. LSP MET Endpoint -> Nikita Search for extreme kinematical configuration q2 q1 gluino squark B tagging h0 b See Luc Pape private note -> endpoints gives equations with unknown mass (gluino, squak, neutralinos) -> system has to be solved numerically Need to look for Hq1, hq2, hq1q2, q1q2 invariant mass distribution -> for the moment using MC info only Alain Romeyer - January 2005

  15. Alain Romeyer - January 2005

  16. Hq1 / hq2 hq2 hq1 Alain Romeyer - January 2005

  17. hq1q2 / q1q2 q1q2 hq1q2 Alain Romeyer - January 2005

  18. Conclusion • Future : • Include all SM background (W+jets, Z+jets) • Improve S/B ratio (cuts, b tagging optimisation…) • Reduce the width of the invariant mass • Run the code on the Zbb sample for cross check and optimisation of the reconstruction strategy • Fast simulation (FAMOS) in order to explore the SUSY parameter phase space • Contour plot for the CMS reach • PTDR !!! + Analysis note -> setenv CVSROOT :pserver:note@ppemons.umh.ac.be:/var/www/html/cvsweb/cvscvs login -> password is n0teCvs co Analysis_note Alain Romeyer - January 2005

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