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Σ Eγ comparison using Woochun Park Univ of South Carolina Feb 26,

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Presentation on theme: "Σ Eγ comparison using Woochun Park Univ of South Carolina Feb 26,"— Presentation transcript:

1 σ Eγ comparison using Woochun Park Univ of South Carolina Feb 26, 2005 @EMC

2 Photon energy resolution (BaBar Note# 583) σ γ has more than an estimate of photon energy resolution since it includes track momentum uncertainty. We subtract this effect in quadrature after estimating: We are not able to distinguish Xc1 and Xc2, so ΔM (Mχ ci - M J/ψ ) < 0.447: M PDG χ c =M PDG xc1 else M PDG χ c =M PDG xc2. (Need to study about σ Eγ dependence on χ ci. More ideas in page 8-9.)

3 Selecting samples Following BAD#139, “Inclusive charmonium state analysis in B” Analysis 23 (14.5.5) SP5 MC Jpsitoll skim:AllEvents: 2.25%; B0B0b: 4.78%;B+B-: 5.36%; ccb: 5.67% For J/ψ (only for μμ today): –With radiation recovery. Selectors are not decided yet. –One “Tight” muon and one “Very Tight” muon (cut opt. in next page). –Geometric constraint on vertex. –p* J/ψ < 2.0 GeV/c, M ee is not decided. and 3.06 < M μμ < 3.13 GeV. For χ c1,2 : –GoodPhotonLoose List –Zernike(4,2) moment < 0.15 –Reject photons from π 0 candidate with no constained mass b/w 0.117 and 0.147, Emin = 30MeV, Lat < 0.8 –0.12 < E γ < 1.0 GeV –To suppress hadronic split-offs, photon should be at least 9 degree from any charged tracks. –p* < 1.7 GeV/c

4 J/ψ→μμ Optimization For each muNN cuts, estimate signal and background with all cuts applied in signal window, 3.06 < M μμ < 3.13 GeV. Run1 data used. (muNNTight, muNNVeryTight) is selected based upon S 2 /B. muNNSignalBGS/BS 2 /B VL 17257.6 / 190.13412986.4 / 1611.611.3322934 VL L17198.6 / 191.59712246 / 1564.991.4024154 VL T16788.1 / 179.5569826.95 / 1401.921.7128680 VL VT16200.7 / 172.5658587.19 / 1310.511.8930564 L 15414.6 / 167.6398001.1 / 12651.9329697 L T15250.4 / 163.1027181.98 / 1198.52.1232383 L VT14815.2 / 158.3666495.07 / 1139.742.2833793 T 12418.3 / 139.5614301.81 / 927.5572.8935849 T VT12261.5 / 138.2224175.4 / 913.8272.9436007 VT 9771.77 / 121.7033047.39 / 780.6913.2131334

5 Off-resonance(error) vs cont MC(line) Offdata = 56±7.5 (2.35 fb -1 ) contMC = 50.1±2.7 Ratio = 1.12 ± 0.16 Using J/ψ → μ μ (Run1) Muon efficiency correction would make them more inconsistent. There is no clear peak from continuum BG. Easy to model BG shape. Shapes are consistent b/w OnPeak & BBMC. On-resonance(error) vs MC(line) Ondata = 7692±88(19.5 fb -1 ) BBMC+scaled Offdata = 5892±77 Ratio = 1.31 ± 0.02 Life becomes simple if data is like this!!!

6 E true E meas E calc MC DATA For all E meas spectrum (50MeV binnings will be in next page)

7 Divide E meas by 50MeV from 200MeV and 800MeV. Fit each plot with Gaussian+Pol1. Subtract track momentum uncertainty in quadrature. BB MC DATA Next page

8 RESULT Data and MC looks consistent except [400, 450] MeV in E meas. More statistics come from J/ψ→ee. Ntuple generations are very smooth. Higher priority on batch queue usage will definitely help me to get faster results. RUN2 D*->D0 gamma [400, 450] E meas DATA MC DATA MC

9 DATA

10 σ Eγ dependence on M χc1,2 Assuming that we mis-assign X c1 mass to X c2 (X c2 decay width (2.11±0.16 MeV) is about twice bigger than X c1 (0.91±0.13 MeV). ) –ΔM Xc = -46MeV ( M Xc1 = 3510.59 MeV : M Xc2 = 3556.26 MeV ) –δE calc ~ -2 ( ΔM Xc ) M Xc ≈ -0.325 GeV 2 –M Xc PDG 2 - M ψ PDG 2 ≈ 2.85 GeV 2 –δE calc ≈ -0.11 E calc (mis-assignment causes 11% error in E calc per event.) –δσ Eγ = -0.11/ E calc ≈ -25% per event when E calc = 0.44 GeV If we are confused in DATA as much as MC, it’s just fine on the purpose of measuring relative photon energy resolution. –We need to estimate how much different mis-assignment rate between MC and DATA. –Maximum likelihood fit on σ Eγ and R(Y xc1 /Y xc2 ) could be one alternative way. R measurement could be a physics topic, “inclusive Xc braching ratio analysis”.

11 Very preliminary Study on R (Run1) –eMicroVeryTight and eMicroTight w/o radiation recovery electron. –muMicroTight and muMicroLoose –3.05 < M ee < 3.12 and 3.07 < M μμ < 3.12 GeV. –Fit with Gaussian + Pol2 Signal MC BB MC OnData R=2.46 ± 0.07(sigMC) R=4.06 ± 0.75 (BB MC) R=11.6 ± 4.7(OnPeak) PDG R= 4.54 ± 1.59

12 More presentation is advised at EMC software/calibration meeting tomorrow. Δ(σEγ)Δ(σEγ) Δ(δσEγ)Δ(δσEγ) X-axis is E calc (page 8 has E meas x-axis) δσ Eγ /E calc σ Eγ /E calc DATA MC DATA MC J/ψ →μμ Run1

13 To-do Move on to Run4 to take advantage of the best statistics dataset. Simulate combinatoric background. study about σ Eγ dependence on χ ci μ efficiency correction to compare MC with DATA. Question How to include μ efficiency correction?? With 2 month-old in BaBar, it’s very difficult to find. –I tried ntpBlockContents set "mu : Momentum CMMomentum MCIdx PIDWeight(muNNTight)“ –It only gives me 1.0 weight and 0 status all the time which doesn’t see to reasonable. –Then, I include pidCfg_mode tweak * and pidCfg_mode weight * –But, my BtaTupleApp doesn’t recognize pidCfg_mode command.


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