1. f  K+K- analysis in Run4 Au-Au collisions at √sNN = 200 GeV
Dipali Pal
Vanderbilt University
Light/Heavy PWG meeting
May 05, 2005 1

2. Event and track selection
Used minimum bias CNT files from Stripe-1,2 and 3 at RCF.
|bbcz| < 30 cm & valid reaction plane angle (rp12)
Total number of events analyzed
+ + field runs: 120 M
- - filed runs: M
Track selection:
 DC quality 31 or 63, |zed| < 75 cm
 3s match in z and f at TOF (TOF analysis)
 3s match at PC3 and PbSc (PbSc analysis)
 etof > 2 MeV at TOF
 2s kaon PID cut at TOF
 0.2 < m2 < 0.3 GeV2/c4 tracks as kaons in PbSc
 Pair cuts: DC Ghost rejection and TOF/ PbSc intruder rejection. 2

3. fK+K- invariant mass spectra TOF - TOF
Minimum-bias (0 – 90%) events.
Normalization: 2√N++N– method
Fitted with Relativistic Breit Wigner convolved with Gaussian phi mass resolution, s = 1.2 MeV/c2 3

4. fK+K- invariant mass spectra TOF - East
K+ from TOF, K- from PbSc(e)
K- from TOF, K+ from PbSc(e)
Minimum-bias (0 – 90%) events.
Normalization: 2√N++N– method
Fitted with Relativistic Breit Wigner convolved with Gaussian phi mass resolution, s = 1.2 MeV/c2 4

5. fK+K- invariant mass spectra East - East
Minimum-bias (0 – 90%) events.
Normalization: 2√N++N– method
Fitted with Relativistic Breit Wigner convolved with Gaussian phi mass resolution, s = 1.2 MeV/c2 5

6. fK+K- invariant mass spectra West-West
Minimum-bias (0 – 90%) events.
Normalization: 2√N++N– method
Fitted with Relativistic Breit Wigner convolved with Gaussian phi mass resolution, s = 1.2 MeV/c2 6

7. fK+K- invariant mass spectra Full dataset
Minimum-bias (0 – 90%) events.
Normalization: 2√N++N– method
Fitted with Relativistic Breit Wigner convolved with Gaussian phi mass resolution, s = 1.2 MeV/c2 7

8. Line shape of f at different centralities-18

9. Line shape of f at different centralities-29

10. Line shape of f at different centralities-3
80 – 90% 10

11. Line shape of f at different centralities-411

12. Summary
fK+K- invariant mass spectra has been studied for different subsystem combinations.
Reconstructed ~39450 f mesons from 207 M events.
A first look at the line shape for a large number of centrality bins. 12

13. Backup slide: Run2 & Run4 dead areas