ALICE Physics Week, Muenster, 13.02.07 Andrea Dainese 1 Status of B analysis Status of B analysis via single electrons via single electrons Andrea Dainese Andrea Dainese INFN – Legnaro INFN – Legnaro based on work with: based on work with: F.Antinori, C.Bombonati, M.Lunardon, R.Turrisi F.Antinori, C.Bombonati, M.Lunardon, R.Turrisi
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ALICE Physics Week, Muenster, 13.02.07 Andrea Dainese 1 Status of B analysis via single electrons Andrea Dainese INFN – Legnaro based on work with: F.Antinori,
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ALICE Physics Week, Muenster, 13.02.07 Andrea Dainese 1
Status of B analysisStatus of B analysisvia single electronsvia single electrons
Andrea DaineseAndrea Dainese
INFN – LegnaroINFN – Legnarobased on work with: based on work with:
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First-year scenario
Only few TRD supermodules for 2008 pp run
What can we do with TPC(&TOF) PID only?
Optimization of dE/dx cuts for electrons ID
Ne=N=N=NK=Np
p=4 GeV/c
40%
0.1%
TOF
C.Bombonati
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First year: Statistical error
TPC+TRD TPC
C.Bombonati
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OutlookOne year at nominal luminosity:
pp 1-18 GeV/c ➔ comparison with pQCD calc.Pb-Pb 1-18 GeV/c ➔ RAA & v2 of beauty
First year pp:up to 14 GeV/c (with larger errors) using ITS+TPC+TOF
Next steps:preparation of Analysis task for ESD/AODanalysis of PDC eventspreparation of procedure for background subtraction (charm, misid. pions) and for corrections (cuts, PID)
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EXTRA SLIDES
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LHC running conditions
Ldt = 5.1026 cm-2 s-1 x 106 s
5.1032 cm-2 PbPb run, 5.5 TeV
NPbPb collisions = 2 .109 collisions
Ldt dt = 3.1030 cm-2 s-1 x 107 s
5.1037 cm-2 for pp run, 14 TeV
Npp collisions = 2 .1012 collisions
Muon triggers: ~ 100% efficiency, ~ 1kHz Electron triggers: Bandwidth limitation NPbPb central = 2 .108 collisions
Muon triggers: ~ 100% efficiency, < 1kHz
Pb-PB nominal run pp nominal run
Electron triggers: ~ 50% efficiency of TRD L1 20 physics events per event
Hadron triggers: NPbPb central = 2 .107 collisions
Hadron triggers: Npp minb = 2 .109 collisions
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Model Comparisons(HERA-LHC Workshop)
Compare predictions by several different models
Good agreement between collinear-factorization-based calculations: FO NLO and FONLLkT factorization (CASCADE) higher at large pT
beautycharm
CERN/LHCC 2005-014hep-ph/0601164
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Energy extrapolation via pQCD?
Different systems (pp, p-Pb, Pb-Pb) will have different s values
Results in pp at 14 TeV will have to extrapolated to 5.5 TeV (Pb-Pb energy) to compute, e.g., nuclear modification factors RAA
pQCD: “there ratio of results at 14 TeV/5.5 TeV has ‘small’ uncertainty”
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Cuts Summary
pt bin [GeV/c]
|d0| cut [m]
1.0 – 1.5 400 200
1.5 – 2.0 400 200
2.0 – 2.5 300 200
2.5 – 3.0 200 200
3.0 – 4.0 150 200
4.0 – 5.0 150 200
5.0 – 7.0 100 200
7.0 – 9.0 100 200
9.0 – 12.0 100 200
12.0 – 16.0 50 200
16.0 – 20.0 50 200
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- Charmed hadrons (Hc=D0,D+,D+s,+
c) cross section assumed to be proportional to the D0 one. The Hc/D0
ratio is assumed to be 1.70 0.07 (*)
Errors propagated from Hc to e level:
- Monte Carlo corrections for the D0 measurement ~ 10%
- Statistical error on the D0 pT distribution
- NN normalization not considered at this level (same as beauty)
- The 69% uncertainty of D0 from b should become negligible after the beauty direct measurement
The charm contribution to the total electron spectrum is evaluated using the MC by introducing the charmed hadron pT distributions deduced from the D0K-+ measurement.
Estimation of uncertainties on the pT - differential cross section of beauty electrons
evaluation of charm background
(*) deduced by comparing the PYTHIA value with the ALEPH measured value [D.Abbaneo et al., Eur. Phys. J. C16 (2000) 597]
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