ICSHEP 8, Apr , 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 , 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 , 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. D (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 , M.C. data samples  BtoJpsiMuMu 2.5M events ~100pb-1  JPsiMuMu 2.0M events ~16pb-1  InclusivePPmuX 5.3M events ~0.044pb-1 events normalized or scaled to:  Inclusive b: 253,600  P-J/Psi: 1,150,000  Inclusive PPmuX: 5,132,579 Scale: >1,188,000,000 Early Data with 10 pb-1 analysis

ICSHEP 8, Apr , 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 = mb Br(b → J/ΨX) = Br(J/Ψ → μμ) filterEfficiency ε=  σeff =σgen_tot*εfilter*Br = 25.36nb

ICSHEP 8, Apr , 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/c 2 Further on ppdl:  ppdl: [-0.1,0.5]cm, error_ppdl<0.1cm

ICSHEP 8, Apr , Measurement of b production Cross-secton dt : the integral luminosity f b : fraction for J/Ψ from b  P T : the size of the P T bin. : the number of reconstructed J/  signals A: geometric and kinematic acceptance of J/ψ candidates  Trig,,  reco : trigger and recon efficiency from M.C. : correction on trigger and recon efficiency from Tag&probe The inclusive b differential cross-section is calculated as Unfolding: pT Jpsi-> b

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

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

ICSHEP 8, Apr , Mass & ppdl fitting: resol. Model Sum08 Mass: 3Gaussion Pdl: 2Gaussion

ICSHEP 8, Apr , b ctau at Gen Ctau_b: 467 micron

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

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

ICSHEP 8, Apr , J/psi: b fraction & Acceptance, Trig eff. Acceptance Trig. Eff. Unbinned combined MLH fit & analysis method: 10pb-1 “ data ” PT: 5-40 GeV/c Reco “ Data ” J/psi 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 , J/psi & b production 10TeV J/psi pT spetrum -> b hadrons pT ’ s J/Psi from b Hb pp → bbX ~ 430 μb (10 TeV) pp → bbX ~ 315 μb (7 TeV)

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

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

ICSHEP 8, Apr , Unfolding correlation Matrix

ICSHEP 8, Apr , J/psi pT spetrum -> b hadrons pT’s J/Psi from b Hb

ICSHEP 8, Apr , Hb production 10TeV Gen Gen+filter

ICSHEP 8, Apr , 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 , CMS QTF group

ICSHEP 8, Apr , CMS Muon Trigger Strategy

ICSHEP 8, Apr , CMS data: Preliminary Fill HF Vtx Totals /ub

ICSHEP 8, Apr , THANKS!

ICSHEP 8, Apr , BACKUPS

ICSHEP 8, Apr , 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 , Inv. Mass of J/  vs diff. pT bin CDFII