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Status report - Tracking code -

This report presents the debugging processes and simulation efforts aimed at improving tracking efficiency within the HKS framework, specifically focusing on the 52Cr target. Key aspects include test point calculations, drift time adjustments, and the impact of high multiplicity events on data analysis. The analysis highlights bugs in the current tracking code and proposes necessary corrections, such as addressing the y-coordinate sign discrepancies in test point selections. The simulation results underscore improvements in tracking efficiency, alongside the need to develop routines for rejecting background noise and optimizing hit detection.

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Status report - Tracking code -

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  1. Status report- Tracking code - T.Gogami 9/30/2010

  2. Content • Debug • test point • drift time • Simulation for tracking efficiency • e,e+ background

  3. Test point calculation in pattern recognition for HKS Test point coordinate ( x , y ) y-coordinate sign is opposite ! http://lambda.phys.tohoku.ac.jp/~gogami/HES-HKS/testpoint/testpoint.pdf But in current code • There is no affection to select space points. • But this affect in “h_tof_pre.f”. • (this case is so rare)

  4. Clusters in residual vs. χ2 distribution Longer drift time events make clusters x’ [rad] Track χ2 x [cm] Single residual (KDC1-3) [cm] Drift time [ns]

  5. h_tof_pre.f • pre track with space points • single hit in KTOF • multi hit in KTOF • start time calculation for drift time of chambers • correction (card)

  6. Bugs in h_tof_pre.f start time for drift time KTOF TDC information • single hit • multi hit (mean)

  7. Residual vs. χ2 CH2 target Current CH2 target Current Disappear clusters New CH2 target New 16 % for 52Cr target 40%

  8. Drift distancex’ vs. residual CH2 target Current Current Residual [cm] (KDC1-3) Stripe drift distance [cm] x’ [rad] @ reference plane New New Residual [cm] (KDC1-3) drift distance [cm] x’ [rad] @ reference plane

  9. Simulation for HKS tracking efficiency (by D.Doi) KTOF1X • input tracks in simulation ==> output file (hit wire info and so on) • input this file to real analyzer • see output tracks and compare to input tracks K+ KDC2 KDC1 one result of this simulation CH2 target Current analyzer cannot handle with high multiplicity data 52Cr target Need to improve tracking code Now developing

  10. e,e+ b.g. in HKS TOP view 5 × 5 [cm2] Side view HKS - D HKS - Q X’ [rad] X [cm]

  11. B.G mix rate in HKS trigger a just after pattern recognition ==>cut bad combination of space point (like h_tof_pre) ==> Saving CPU power , Reduce analysis time 52Cr (77124) b 12C (76077) 9Be (76607) 7Li (76184) . 10B (76184) B.G. mix rate = a/(a+b) ×1044 Developing B.G. cut routine

  12. Multiplicity in chambers HES layer 10 6 after TDC cut 52Cr target CH2 target mean ~ 1 hit mean ~ 1 hit ~2 [MHz] (8 [μA] on 52Cr) HKS after TDC cut 6 6 layer 52Cr target CH2 target mean ~ 6 hit mean ~ 2 hit ~18 [kHz] (8 [μA] on 52Cr) Origin of high multiplicity is ee+ B.G. ?

  13. Summary and to do • Summary • debug • test point calculation in “find space point” • opposite sign for y-coordinate of test point • ( finalminnum--> finalminnum+1 ) in “h_tof_pre.f” • drift time distribution got better • entry number is up (CH2:16% up , 52Cr:40% up) • Simulation for HKS tracking efficiency by D.Doi • e,e+ B.G • mix rate is high especially for 52Cr target. • need to cut before tracking • Origin of high multiplicity ? • to do • Development • reject e,e+ B.G routine • choose single hit routine --> see all combination • Check • HES side tracking code • e,e+ B.G origin ? • check ADC • Simulation

  14. Generated e+ in Simulation pe+ : 1.2±0.5 [GeV/c] θ : 0.124±0.124 [rad] φ : 2.64159±0.5 [rad] target : 12C 100[mg/cm2] HKS D magnet HKS D magnet Splitter magnet beam: spherical uniform generation no collimator EM flag on

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