1. Estimate of META efficiency in NOV02 Aim: check of META efficiency implemented in digitizers in order to get proper efficiency correction of yields Needed: noise free sample of tracks from MDC spline tracks - only 66% match with TOF hit RK tracks - 90% match with TOF hit Result: estimate of lower limit of META efficiency crosscheck needed P. Tlustý Krakow, March 4, 2006

2. History Smolenice 2002 TOF efficiency no mag. field - all tracks no tracking - matching of inner and outer mdc segments by hand Conclusion - TOF efficiency as expected

3. Method Nov. 2002 gen4 dst’s -> “pdf ntuples” from PidTrackCandidate data - 20 M events (days 348-350) UrQMD simulations - 30 M events selection of tracks: inner mdc segment  2 > -1, RK  2 > 1000, SplineAccepted=1, RKAccepted=1 3 types of tracks - 1) negative with mom>400 MeV/C „pi-“ 2) positive with mom>400 MeV/c „p“ 3) tracks matched to RICH „e“

4. Method efficiency calculated as ratio N METAmatched /N all in theta-momentum space

5. Results EXP data - yields vs theta black - all tracks red - matched with META efficiency

6. Results EXP data - yields vs phi black - all tracks red - matched with META efficiency

7. Results SIM data - yields vs theta black - all tracks red - matched with META green - „good“ tracks efficiency

8. Results SIM data - yields vs phi black - all tracks red - matched with META green - „good“ tracks efficiency

9. Results -  - META efficiency vs theta black - EXP red - SIM green - Shower eff (Jurek)

10. Results -  - TOF efficiency in 50 < theta < 80 region sector 0 0.893 ± 0.003 sector 3 0.922 ± 0.004 SIM 0.967 ± 0.003

11. Conclusions Negative tracks with reasonably high momenta can be used for such kind of study, we can get at least relative numbers of META efficiency (sector comparison etc.). Any absolute correction should be done carefully.

12. Results AUG04 -  - META efficiency vs theta black - EXP red - SIM TOF efficiency sector 0 0.930 ± 0.005 1 0.919 ± 0.004 3 0.920 ± 0.005 4 0.940 ± 0.005 SIM 0.963 ± 0.005

14. NOV02 gen4 - negative tracks vs phi much better than Nov02 gen3 SYS 0 SYS 1

15. NOV02 gen4 - negative tracks vs theta differences between sectors SEC 0 SEC 3

17. Hadron acceptance and efficiency calculation November 2002 hadron analysis UrQMD simulations - 54 M events (gen4 dst) used selection of particles: GeantKine id, parent_id=0 selection of tracks: PidTrackCandidate, id, correlation flag: mdc0,mdc1,meta RK tracks matched to META inner mdc segment  2 > -1, RK  2 > 1000, SplineAccepted=1, RKAccepted=1 tracks with TOFINO paddle multiplicity =1 all particles written to tree, histogramms filled as the 2nd step for each sector independently

18. HADES acceptance acceptance calculated from SIM data as ratio N rectracks /N primary for p,  +,  - in theta vs momentum Binning: theta 2 deg, momentum 25 MeV/c Range: theta 0-100 deg, momentum 0-2000MeV/c

19. Corrected particle yields