1. Hadron PID recalibration in EMCAL (Au-Au @200 GeV dataset)
Dipali Pal and Debsankar Mukhopadhyay
05/10/2005

2. Outline Run4 200 GeV Au-Au stripe –2 dataset PbSc east and west
Timing calibration was done by SUNY Phys.
PID functions: isPi, isK and isP
-- Fit mass-squared distributions at different momentum slices within 0.2 < p(GeV/c) < 2.2.
-- Determine centroids and s’s of m2 distribution for pi, K and p at different momenta.
-- Study and parametrize s vs p and centroid vs p.
-- PID function:
isN = [m2(measured) – m2(parametrized)]/s
N = pi, K, p

3. Analysis Events: Minimum-bias CNT files |bbcz| < 30 cm
Tracks: 3s matching at PbSc
Used Sarah’s EmcTof timing recalibrator via master recalibrator module under fun4all.

4. Studying PbSc PID ranges from m2 distributions (Negative tracks) -- 1

5. Studying PbSc PID ranges from m2 distributions (Negative tracks) -- 2
Summary:
PID starts from p = 0.3 Gev/c
Protons are visible from p = 0.5 GeV/c
All p, K, p are separated within 0.5 – 1.0 GeV/c
p and K are separated within 0.3 < p (GeV/c) < 1.0
Both p and p are visible upto p = 2.0 GeV/c

6. Studying PbSc PID ranges from m2 distributions (Positive tracks) -- 1

7. Studying PbSc PID ranges from m2 distributions (Positive tracks) -- 2
Summary:
PID starts from p = 0.3 Gev/c
Protons are visible from p = 0.5 GeV/c
All p, K, p are separated within 0.5 – 1.0 GeV/c
p and K are separated within 0.3 < p (GeV/c) < 1.0
Both p and p are visible upto p = 2.0 GeV/c

8. m2 distributions and fitting – p(1)
Fitting function:
Gaussian (signal)+
second order polynimial(BG)
Centroids and s’s within
0.4 < p(GeV/c) < 1.2 GeV/c

9. m2 distributions and fitting – p (2)
p <m2> Dm s Ds
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10. m2 distributions and fitting – p (3)
p <m2> Dm s Ds
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11. m2 distributions and fitting – Kaon
Fitting function:
Gaussian (signal)+
Exponential (BG)
Centroids and s’s within
0.4 < p(GeV/c) < 1.0 GeV/c

12. m2 distributions and fitting parameters: K+
p <m2> Dm s Ds
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13. m2 distributions and fitting parameters: K-
p <m2> Dm s Ds
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14. m2 distributions and fitting – protons
Fitting function:
Gaussian (signal)+
Exponential (BG)
Centroids and s’s within
0.5 < p(GeV/c) < 2 GeV/c
p-bar looks different from p at higher momenta.

15. m2 distributions and fitting parameters
anti-proton
proton
p <m2> Dm s Ds
p <m2> Dm s Ds
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16. m2 Centroids vs momenta Centroids are fitted with 3rd order polynimial
as functions of p:
p0 + p1*x + p2*x2 + p3*x3
p p p p3 p+ p- K+ K- P
P-bar
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17. Sigma vs momentum: pion
Fitting function:
p0 + p1/x + p2/x2 + p3.x2
p p p p3 p p

18. Sigma vs momentum: kaon
Fitting function:
p0 + p1/x + p2/x2 + p3.x2
p p p p3 K K

19. Sigma vs momentum: proton
P-bar
Fitting function:
p0 + p1/x + p2/x2 + p3.x2
p p p p3 p
p-bar

20. Identified particles

21. Summary
PID calibration functions are completed for run4 200 GeV dataset.
Need to put them in recalibrator and database.