1. Analysis strategy of high multiplicity data Toshiyuki Gogami 24/Feb/2011

2. Contents

3. Introductions

4. Analysis process tracking x, x’, y, y’ at Reference plane x’, y’, p at Target Missing Mass tracking x, x’, y, y’ at Reference plane x’, y’, p at Target F2T function particle ID (select K + ) HKS HES tune This talk

5. Multiplicity and Tracking Tracking 1.Resolution 2.Number of event Multiplicity affect

6. Multiplicity of typical layer in chamber CH 2 target 52 Cr target mean ~ 6 hit mean ~ 2 hit CH 2 target 52 Cr target mean ~ 1 hit 10 6 layer 6 6 HES HKS

7. Multiplicity for each layer TargetRun NumberBeam [μA]Multi KDC1-x (@PR) Multi KDC1-x (@N) Thickness [mg/cm 2 ] CH 2 450.0763142.02.922.72 H2OH2O500.0759722.75.754.93 7 Li184.07622032.04.263.85 9 Be188.17660738.44.734.16 10 B56.17618442.42.522.46 12 C112.57607738.84.424.12 52 Cr154.0771247.66.425.14

8. Singles rate summary target, Run #, current Water 75930 2.8 Carbon 75954 35 Cr 76000 8.0 Carbon 76051 10 Carbon 76080 40 Boron 76150 40 Boron 76180 45 Lithium 76235 35 CH2 76320 2.0 Be9 76590 40 Cr 76700 7.5 Carbon 76830 20 target, Run #, current Water 75930 2.8 Carbon 75954 35 Cr 76000 8.0 Carbon 76051 10 Carbon 76080 40 Boron 76150 40 Boron 76180 45 Lithium 76235 35 CH2 76320 2.0 Be9 76590 40 Cr 76700 7.5 Carbon 76830 20

9. Rate dependences Multiplicity : linear dependence with rate Residual : quadratic dependence with rate

10. Origin of high multiplicity (rate) in HKS

11. Background event from NMR port z [cm] y [cm] x [cm] These particles come from NMR port HKS dipole NMR port KDC1 KDC2 KDC1 KDC2 KDC1 KDC2 KDC1 KDC2 Background event 9 Be, 38.4 [μA] Event on HKS optics

12. B.G. mix rate (real data) TargetRunBeam current [μA]B.G. mix rate [%] CH 2 763142.020.5 H2OH2O759722.744.2 7 Li7622032.010.7 9 Be7660738.414.4 10 B7618442.49.9 12 C7607738.819.3 52 Cr771247.658.7 Ranktarget 1 52 Cr 2H2OH2O 3CH 2 4 12 C 5 9 Be 6 7 Li 7 10 B a b

13. e + simulation SIMULATION To see Positron’s – Number of event – Angle & momentum at the target

14. Target thickness dependence (Simulation) H2OH2O 52 Cr 9 Be 12 C CH 2 10 B 7 Li ranktarget 1 52 Cr 2H2OH2O 3CH 2 4 12 C 5 9 Be 6 7 Li 7 10 B

15. Angle and momentum distribution of positrons HKS cannot accept positrons directly ! Generate these event in HKS GEANT

16. e, e + background in GEANT simulation Vacuum chamber (sus304) NMR port (sus304) KDC1KDC2 e -, e + Generated particle : e + Distribution : spherical uniform Momentum : 860 – 1000 [MeV/c] Angle : 0 – 2 [mrad] 1000 events Number of e + (Simulation) B.G. mix rate (Real data) Correlation e + generated in target make HKS dirty

17. Tracking

18. Basic tracking procedure Good TDC Pattern recognition Track fit Solve left right Select good combination Black : hit wires Blue : selected wires Red : track CH 2 target KDC1 52 Cr target Combination selection with TOF counters Reduce hit wire combinations (h_tof_pre.f) High multiplicity

19. New tracking scheme Good TDC Pattern recognition Track fit Solve left right Select good combination Combination selection with TOF counters Reduce hit wire combinations (h_tof_pre.f) High multiplicity Reduce hit wires to analyze 2 nd loop

20. Cut region selection with TOF Hit Selective region Maximum gradient Minimum gradient Particle direction ~17% ~8% Gravity

21. Multiplicity correlation between KTOF and KDC Multiplicity of KDC are not only high but also TOF counters are! (for heavy target ) CH 2, 76314 52 Cr, 77124

22. Conditions Applied conditions in presented talk – Max. multi in KTOF1X = 4 – Max. multi in KTOF2X = 4 – Allowance = 0 [cm]

23. Real data ( 52 Cr) GREEN region Selective region RED markers Selected hit wires BLACK markers Rejected hit wires

24. Result of TOF cut with grouping Residual Number of event Number of Kaon Analysis time

25. Result of TOF cut with grouping Residual Number of event Number of Kaon Analysis time

26. B.G. event と event on optics のチェレンコフ等の相関

29. Summary and outlook

30. End