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CMS BOnia physics: J /Psi & Inclusive b( J/PsiX) production x-Section

CMS BOnia physics: J /Psi & Inclusive b( J/PsiX) production x-Section. Xiangwei Meng Guoming Chen Institute of High Energy Physics, CAS, Beijing The 8th ICSHEP, NanChang,China Apr 17-19, 2010. Apr. 18, 2010. Outline. Motivations Data samples Analysis strategy

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CMS BOnia physics: J /Psi & Inclusive b( J/PsiX) production x-Section

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  1. CMS BOnia physics: J/Psi & Inclusive b(J/PsiX) production x-Section Xiangwei Meng Guoming Chen Institute of High Energy Physics, CAS, Beijing The 8th ICSHEP, NanChang,China Apr 17-19, 2010 Apr. 18, 2010 ICSHEP 8, Apr. 17-19, 2010

  2. Outline • Motivations • Data samples • Analysis strategy • Acceptance & efficiency • Unbinned Combined MLH fit • J/Psi production X-section • Unfolding: J/Psi->Hb spectrum • Systematic Uncertainties • Summary ICSHEP 8, Apr. 17-19, 2010

  3. Motivations • First measurement of Jpsi & b hadrons production x-section at sqrt(s) = 7(14) TeV --the same strategy as CDFII’s on Jpsi & inclusive b measurement. Phys. Rev. D71 032001(2005) • Test of QCD calculations • Essential measurement of background for many other processes, validation of b-tagging • The meanwhile study on inclusive b lifetime • calibrate resolution function • understand calibration & alignment ICSHEP 8, Apr. 17-19, 2010

  4. M.C. data samples pp@10TeV • BtoJpsiMuMu 2.5M events ~100pb-1 • JPsiMuMu 2.0M events ~16pb-1 • InclusivePPmuX 5.3M events ~0.044pb-1 Early Data with 10 pb-1 analysis events normalized or scaled to: • Inclusive b: 253,600 • P-J/Psi: 1,150,000 • Inclusive PPmuX: 5,132,579 Scale: 231.5->1,188,000,000 ICSHEP 8, Apr. 17-19, 2010

  5. EvtGen: inclusive b • EvtGen with inclusive b → J/ΨX, J/Ψ → μμ Filter on 2 μ with pT>2.5 GeV/c, |η|<2.5 • σgen_tot = 51.56 mb (@10TeV), Br(b → J/ΨX) = 0.0116 Br(J/Ψ → μμ) 0.0593 filterEfficiency ε= 0.0007139 • σeff =σgen_tot*εfilter*Br = 25.36nb ICSHEP 8, Apr. 17-19, 2010

  6. Event Reconstruction & selection • Global mu: pT> 3 GeV/c, |η|<2.4 • KalmanVertexFitter on μ+μ- pairs, i.e. 2mus sharing the same vertex • Jpsi Mass window: [2.8, 3.4] GeV/c2 Further on ppdl: • ppdl: [-0.1,0.5]cm, error_ppdl<0.1cm ICSHEP 8, Apr. 17-19, 2010

  7. Measurement of b production Cross-secton The inclusive b differential cross-section is calculated as Unfolding: pT Jpsi-> b • dt : the integral luminosity • fb : fraction for J/Ψ from b • DPT : the size of the PT bin. • : the number of reconstructed J/y signals • A: geometric and kinematic acceptance of J/ψ candidates • eTrig, ,ereco : trigger and recon efficiency from M.C. • : correction on trigger and recon efficiency from • Tag&probe ICSHEP 8, Apr. 17-19, 2010

  8. Acceptances • Acceptances include the detector geometric and kinematic acceptances, Can be obtained by Monte Carlo simulation. is treated and defined as: ICSHEP 8, Apr. 17-19, 2010

  9. Trig. Efficiency vs. pT : JPsi’s L1MuOpen loose L1 mu trigger selection • The L1T/HLT efficiency is calculated based on the numbers of an offline reconstructed J/psi passes or not corresponding triggers ICSHEP 8, Apr. 17-19, 2010

  10. Trig. Efficiency vs. η: JPsi’s L1MuOpen • The L1T/HLT efficiency is calculated based on the numbers of an offline reconstructed J/psi passes or not corresponding triggers ICSHEP 8, Apr. 17-19, 2010

  11. Mass & ppdl fitting: resol. Model Sum08 Mass: 3Gaussion Pdl: 2Gaussion ICSHEP 8, Apr. 17-19, 2010

  12. b ctau at Gen Ctau_b: 467 micron ICSHEP 8, Apr. 17-19, 2010

  13. Fit techniques: UCMLH fit (mass, ppdl) Unbinned combined MLH fit & analysis method: 10pb-1 “data” PT: 5-40 GeV/c Offline p-jpsi: 11545 b: 4288 a finite experimental resolution on each measurement FI(t) = exp(-t/τ) FR(t) = exp(-t/τ) ⊗ G(t,μ,σ) ≡ ε(t)·∫ dt’exp(-t’/τ) G(t-t’,μ,σ) FE(t,dt) = ε(t)·exp(-t/τ) ⊗ G(t,μ,s⋅dt) (t/dt) fitting with RooFit package pT: 9-10GeV ICSHEP 8, Apr. 17-19, 2010

  14. Fit results: Jpsi Pt bins 5-6, 30-40GeV/c p-jpsi: 15126 b: 1801 p-jpsi: 1060 b: 762 ICSHEP 8, Apr. 17-19, 2010

  15. J/psi: b fraction & Acceptance, Trig eff. Unbinned combined MLH fit & analysis method: 10pb-1 “data” PT: 5-40 GeV/c Acceptance Reco “Data” J/psi Trig. Eff. Prompt Jpsi(270k):15280, 32380, 40792, 39592, 34183, 26992, 21016, 15768, 11764, 8671, 11603, 8691, 4884, 2579, 1074 Jpsi(b hadrons)(68k): 1647, 4439, 6960, 8131, 8037, 7245, 6259, 5324, 4319, 3219, 4590, 3976, 2611, 1502, 749 ICSHEP 8, Apr. 17-19, 2010

  16. pp → bbX ~ 430 μb (10 TeV) pp → bbX ~ 315 μb (7 TeV) J/psi & b production x-section@pp 10TeV J/psi pT spetrum -> b hadrons pT’s Hb J/Psi from b ICSHEP 8, Apr. 17-19, 2010

  17. Unfolding Gen b hadron Gen+filter b hadron Unfolding Gen+filter J/psi Detector response Eff_Trig Reco b hadron Eff_Reco Reco J/psi *Distortions between pT distribution of b hadrons and J/Ψ from them ICSHEP 8, Apr. 17-19, 2010

  18. Unfolding methods I • Bin-to-bin correction: no into account migrations a bin to the others; neglect correlation between adjacent bins. • The matrix method: solve the problem of migrations; singular problem; statistical fluctuations; results unstable. • Regularized unfolding: satisfactory results but technical complications; only with one dimension ICSHEP 8, Apr. 17-19, 2010

  19. Unfolding Method II: Bayes’ A Multidimensional unfolding method based on Bayes' theorem by G.D'Agostini, Nucl. Instr. Meth. A362 (1995) 487-498. Ci: cause in i-th bin: Ej: effect in j-th bin P(Ci|Ej): corelation matrix for Ej to Ci ICSHEP 8, Apr. 17-19, 2010

  20. Unfolding correlation Matrix ICSHEP 8, Apr. 17-19, 2010

  21. J/psi pT spetrum -> b hadrons pT’s Hb J/Psi from b ICSHEP 8, Apr. 17-19, 2010

  22. Hb production x-section@pp 10TeV Gen+filter Gen ICSHEP 8, Apr. 17-19, 2010

  23. Systematic Uncertainties • Luminosity ~10% • Branching fractions ~9.6% • Acceptance& efficiency • Jpsi polarization: CDF-II & BaBar 2-7% • pT spetrum: flat pT distribution needed 0−5%. • M.C. simu. stat. 0.7 − 1.3%. • Signal number: Mass pdf; moumentum scale; misalignment pdl pdf: resolution model; Hb lifetime medol; background pdf 1-6.5% • Eff. Reconstruction: M.C. Truth & tag&probe corr. ~3% • Eff. Trigger: M.C. Truth & tag&probe corr. ~3% • Unfolding: Jpsi-> Hb • Hb production spectrum: PYTHIA 2-7% • Hb->Jpsi decay spectrum: EvtGen 0.5-3% • eff. For unfolding correlation: limited pT region <1% • First CMS 10pb-1 data in pT [5,40] GeV/c limited by systematic uncertainties • J/ : ~10-15% inclusive b hadrons: ~15-22% ICSHEP 8, Apr. 17-19, 2010

  24. CMS QTF group ICSHEP 8, Apr. 17-19, 2010

  25. CMS Muon Trigger Strategy ICSHEP 8, Apr. 17-19, 2010

  26. CMS pp@7TeV data: Preliminary Fill 1005-1022 HF Vtx Totals 111.17 113.86 /ub ICSHEP 8, Apr. 17-19, 2010

  27. THANKS! ICSHEP 8, Apr. 17-19, 2010

  28. BACKUPS ICSHEP 8, Apr. 17-19, 2010

  29. CDFII’s result • PPbar energy: 1.96 TeV. • Integrated luminosity: 39.7 pb-1. • Jpsi 6.9%+(pT) Inclu b 3-13% ICSHEP 8, Apr. 17-19, 2010

  30. Inv. Mass of J/ vs diff. pT bin CDFII ICSHEP 8, Apr. 17-19, 2010

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