Mapping separation power Klaus Gtzen GSI Darmstadt PID

Mapping separation power Klaus Götzen GSI Darmstadt PID TAG Meeting 15. Feb. 2007 K. Götzen PID TAG Meeting – EVO – 15. 02. 08

Central Problem • Problem: – What is necessary PID quality for PANDA, i. e. what minimal set of PID detectors is needed? . . . or to be more exact: – How much separation power do we need in which phase space region to reach our physics goals? • Answering implies: 1. How good is separation over phase space? 2. Where is significant kinematic signal/background overlap? K. Götzen PID TAG Meeting – EVO – 15. 02. 08 2

PID information • Attempt to answer question No 1. • At the moment: almost no reco‘d PID info from Full Sim • Consider parametrized PID info in Fast Sim from det‘s – – – Barrel DIRC ( C) Endcap DIRC ( C) Forward RICH ( C) Straw Tube Tracker (d. E/dx) Micro Vertex Detector (d. E/dx) Barrel TOF (m 2) tcb tcd tcr des dem mt • Dataset: 200 k isotropic ( , p) single track events of every particle type (e, , , K, p) 0° < < 180° 0. 15 Ge. V/c < p < 8 Ge. V/c K. Götzen PID TAG Meeting – EVO – 15. 02. 08 3

Quality check C barrel DIRC endcap DIRC p [Ge. V/c 2] K. Götzen forward RICH p [Ge. V/c 2] d. E/dx p [Ge. V/c 2] STT C MVD p [Ge. V/c 2] PID TAG Meeting – EVO – 15. 02. 08 p [Ge. V/c 2] m 2 C TOF p [Ge. V/c 2] 4

Method • Divide 2 -D p, region into bins • for every bin & every 2 PID hypothesis (only ‚neighbours‘, i. e. : e- / -K / K-p) – plot the 2 distributions – determine mean values i and RMS ri for both hypothesis (e. g. and K) – separation power (number sigmas) is estimated as – colorize a 2 -D map according to n K. Götzen PID TAG Meeting – EVO – 15. 02. 08 5

Example 1 Barrel DIRC K |p-2. 0|<0. 1 [Ge. V] | -2|<0. 2 K C K = 0. 7955 r. K = 0. 00288 K. Götzen |p-1. 0|<0. 1 [Ge. V] | -2|<0. 2 Barrel DIRC = 0. 8218 r = 0. 00239 (not really gauss‘sch) C K = 0. 7071 r. K = 0. 01436 PID TAG Meeting – EVO – 15. 02. 08 = 0. 8147 r = 0. 00238 6

Example 2 |p-4. 0|<0. 1 [Ge. V] | -2|<0. 2 Barrel DIRC K |p-0. 3|<0. 1 [Ge. V] | -2|<0. 2 STT K C K = 0. 817 r. K = 0. 00243 K. Götzen = 0. 823 r = 0. 00239 d. E/dx = 4. 02 r = 0. 976 PID TAG Meeting – EVO – 15. 02. 08 K = 12. 94 r. K = 6. 015 7

p [Ge. V] Separation e - mu 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 [deg] p [Ge. V] 0 K. Götzen [deg] 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 [deg] PID TAG Meeting – EVO – 15. 02. 08 [deg] 8

p [Ge. V] Separation mu - pi 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 p [Ge. V] [deg] K. Götzen [deg] 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 [deg] PID TAG Meeting – EVO – 15. 02. 08 [deg] 9

p [Ge. V] Separation pi - K 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 p [Ge. V] [deg] K. Götzen [deg] 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 [deg] PID TAG Meeting – EVO – 15. 02. 08 [deg] 10

p [Ge. V] Separation K - p 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 p [Ge. V] [deg] K. Götzen [deg] 6 6 6 5 5 5 4 4 4 3 3 3 2 2 2 1 1 1 0 0 0 [deg] PID TAG Meeting – EVO – 15. 02. 08 [deg] 11

Overall performance Combined n given by expression Of course, there are still some flaws, but this is the preliminary separation power map! K. Götzen PID TAG Meeting – EVO – 15. 02. 08 12

Signal / Background overlap • How does this now apply to our physics cases? • Compare the following: • Evt. Gen: Kaon p- distributions of benchmark channel, e. g. at different pbar momenta (1. 432, 5. 0, 10. 0, 15. 0 Ge. V/c) • DPM Gen: Pion p- distribution at same energies • Determine kinematic overlap regions and look how good separation power is there K. Götzen PID TAG Meeting – EVO – 15. 02. 08 13

p = 5. 0 Ge. V/c p = 1. 432 Ge. V/c ppbar = 1. 432 / 5. 0 Ge. V/c K. Götzen , bkg K, signal product of histo‘s (overlap) PID TAG Meeting – EVO – 15. 02. 08 14

p = 15. 0 Ge. V/c p = 10. 0 Ge. V/c ppbar = 10. 0 / 15. 0 Ge. V/c K. Götzen , bkg K, signal product of histo‘s (overlap) PID TAG Meeting – EVO – 15. 02. 08 15

Combining information K. Götzen PID TAG Meeting – EVO – 15. 02. 08 16

Combining information @ 1. 432 Ge. V/c K. Götzen PID TAG Meeting – EVO – 15. 02. 08 17

Combining information @ 15. 0 Ge. V/c K. Götzen PID TAG Meeting – EVO – 15. 02. 08 18

Combining information problem here? @ 15. 0 Ge. V/c K. Götzen PID TAG Meeting – EVO – 15. 02. 08 19

Summary • Task: Recommendation for minimum set of PID detectors • Attempt to determine – Separation power p- dependent – Regions, where it‘s acctually needed • Limitations – Information based on parametrizations only – No EMC informations so far – Dsitributions are not gaussian does our definition of sep. power make sense here – Due to finite granularity (bin width) artifacts in the map – Is the estimate for the total n , tot correct? K. Götzen PID TAG Meeting – EVO – 15. 02. 08 20