B º  π + π - : status of analysis

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B º  π + π - : status of analysis. Vitaliano Ciulli Riccardo Ranieri Nicolò Magini. Generated B º  π + π -. At least 1 μ p t μ >4 GeV/c lη μ l8 GeV/c lη π l10 GeV/c. ^. A CP sin(2α) b  m - _ _ b  m +. - PowerPoint PPT Presentation

Transcript of B º  π + π - : status of analysis

  • B+-: status of analysisVitaliano CiulliRiccardo RanieriNicol Magini

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Generated B+-ACPsin(2)b m-_ _b m+

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • MC Signal9196 events simulated (4384 digitized)PYTHIA 6.152 CMSIM 122ORCA 5.1.2 (oohit)[ORCA 5.1.2 (digi)]Cross section =4622 fb

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Decay reconstructionForwardKalmanFilter + ConnectionMachinept>0.8 GeV/cll
  • BackgroundBr(BK+-) = (1.720.27)x10-5 4xBr(B+-)5.24 GeV/c2 mass peak 50 MeV/c2 resolution bkg over signalS/B=1/2

    Other Two-body decaysS/B=1/1

    Estimation of Two-body BackgroundS/B1/3CMS-TN 1994/328 CP Violation Study of the Bd+- decay for the Technical Proposal

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • More on BackgroundCMS-IN 2000/053CMS-NOTE 2001/011

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • List of cutsKinematic cuts:ptB>10 GeV/cpt>5 GeV/cI=R0.9952vtx
  • Some plotsptB>10 GeV/c

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Some numbers on signal

    CutsNsimEff.N(60 fb-1)MC signal43841277320Reco B3729.851.0052359001400Kinematic513.117.005325001400Vertex322.073.00320200800Mass167.038.00310500800

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • and background

    CutsNsimEff.N(60 fb-1)MC background11993116x1012Fake B3767.314.005(5.020.08)x1010only Kinematic12(3.20.9)x10-3only Vertex1(2.7-1.7+4.6)x10-4only Mass178.473.035K+V+M0(1.2-0.8+2.0)x10-81.9-1.3+3.2 x105

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • L1+L2 TriggerL1+L2 Trigger cuts pt>10 GeV/c Events used: 11993After trigger: 306Efficiency =2.55%High lumi Rate= 70 KHzCMS-NOTE 2001/011Results on L2 trigger reconstruction in single and di-muon topologies

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Single muon Triggeronly L1+L2 Trigger cuts pt>10 GeV/cSignal Efficiency (9.10.4)%Background Efficiency (2.550.14)%

    Total selection EfficiencySignal(3.40.9)x10-3Background(3.2-2.1+5.6)x10-10

    3 Years Low Luminosity (3x20 fb-1=60 fb-1)Nsig=940250Nbkg=4800-3300+9000N2body=2800800

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Sensitivity to sin(2)Time integrated analysis sensitivity:

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • Concl4 aspects to be investigated further:Two-body decay backgroundestimated 2800800 @ 60 fb-1(events BK needed)Bug-fix on B lifetimethis MC: t=13.85 ps instead of 1.56 ps(decay length normalized to expected one)new MC signal t=1.56 ps (some changes on Vertex cuts efficiencies)

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS

  • usionNew strategies to reject combinatorial background in udsc events(more statistics needed)

    New ideas to enlarge Trigger Rate of signal events

    Risultati recenti sui rivelatori a microstrisce del tracciatore di CMS