Mattione Kaon PID Studies Y2175
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Revision as of 17:48, 25 September 2012 by Pmatt (Talk | contribs) (→Yield %'s & Signal / Background Ratios)
Contents
Reaction
- γ p → Y(2175), p
- Y(2175) → f0(980)0, φ
- f0(980)0 → π+, π-
- φ → K+, K-
- f0(980)0 → π+, π-
- Y(2175) → f0(980)0, φ
- Final State: p, π+, π-, K+, K-
- Events generated with: ΓY(2175) = 61 MeV/c2, t-slope = 5.0, 50.0 < Vertex-Z (cm) < 80.0
Analysis Overview
- For each q = +/- particle in the reaction, all detected q = +/- tracks are tested as to whether or not they are that particle
- e.g. If a q = + track has PID FOM > 1% for both the π+ & K+: allow both combinations (DO NOT take the best FOM as true!)
- Maximum of 8 tracks per event (to cut down on memory spikes).
- The analysis (cuts/histing/kinfits) is then performed on each possible track combination (events are only cut if every one of their track combinations is cut):
- Required 45.0 < Track-Vertex-Z (cm) < 85.0
- EXTREMELY loose mass cuts around each mass peak (typically at the histogram edges): saves time by reducing # of kinematic fits to perform
- Require the combined FOM for PID (χ2 and NDF of all tracks summed together) be > 1%
- Where kinematic fit: Require that the confidence level from the kinematic fit be > 1%
- Mass cuts as illustrated.
Mass Peaks & Kinematic Fitting
- NOTES:
- Plots are shown for "Missing p, VertexP4 KinFit" only.
- Mass Plots: Pre-KinFit is Magenta, Post-KinFit is Teal
- Kinematic Fit Confidence Level is zoomed in: spike at 0 confidence is well off the top of the plot
- For the genr8 background, It wasn't possible to lineup every mass peak (without generating the recoil proton at a bogus mass), so the missing mass peak is a little off-center.
- If a cut is shown, then all "Post-KinFit" plots after that cut include it.
| Plot | genr8 Y(2175) Signal | genr8 Y(2175) Background | bggen Background |
|---|---|---|---|
| Confidence Level |  |
 |
 |
| Missing Mass |  |
 |
 |
| φ Mass |  |
 |
 |
| Y(2175) Mass |  |
 |
 |
Cherenkov Detector Comparison
genr8 Y(2175) Background
- P vs. θ of π+'s as K+ candidates ("All" means all post-analysis cuts, pre-Cherenkov cuts)
- π-'s as K- not shown: identical due to symmetry.
- Plots are shown for "Missing p, VertexP4 KinFit" only.
| Detector | % of Pions That Fail Kaon Cut | Pions That Fail Kaon Cut | Pions That Survive Kaon Cut |
|---|---|---|---|
| No CKOV |  |
NA | NA |
| He DC | 23.57% |  |
 |
| Gas Threshold | 10.24% |  |
 |
| HBRICH | 98.40% |  |
 |
| LHCb RICH | 98.01% |  |
 |
bggen Background
- P vs. θ of π+'s as K+ candidates ("All" means all post-analysis cuts, pre-Cherenkov cuts)
- π-'s as K- not shown: identical due to symmetry.
- Plots are shown for "Missing p, VertexP4 KinFit" only.
| Detector | % of Pions That Fail Kaon Cut | Pions That Fail Kaon Cut | Pions That Survive Kaon Cut |
|---|---|---|---|
| No CKOV |  |
NA | NA |
| He DC | 22.92% |  |
 |
| Gas Threshold | 7.55% |  |
 |
| HBRICH | 56.77% |  |
 |
| LHCb RICH | 60.42% |  |
 |
Yield %'s & Signal / Background Ratios
- ALL data are determined in the signal region (track combinations with invariant mass outside of the signal region are ignored), and from Eγ = 8.5 - 9.0 GeV
Yield %'s
- % of generated events remaining after all cuts (including a final cut requiring that all tracks have the correct THROWN PID)
| Detector / PID Cut | Missing p, No Fit | Missing p, P4 Fit | Missing p, VertexP4 Fit | No Missing, No Fit | No Missing, P4 Fit | No Missing, VertexP4 Fit |
|---|---|---|---|---|---|---|
| No CKOV | 9.66363% | 9.91859% | 7.50864% | 5.08872% | 3.3008% | 2.64085% |
| He DC K: 1 Exclusive |
7.6393% | 7.75866% | 5.92137% | 4.00075% | 2.58191% | 2.06825% |
| Gas Threshold K: 1 Exclusive |
9.34382% | 9.60139% | 7.32316% | 4.92314% | 3.2149% | 2.57775% |
| HBRICH K: 1 Exclusive |
9.17437% | 9.41574% | 7.18456% | 4.83356% | 3.15836% | 2.53028% |
| LHCb RICH K: 1 Exclusive |
9.25765% | 9.51254% | 7.2575% | 4.87959% | 3.19227% | 2.55721% |
Signal / Background Ratios
- Signal / Background Ratios
| Detector / PID Cut | Missing p, No Fit | Missing p, P4 Fit | Missing p, VertexP4 Fit | No Missing, No Fit | No Missing, P4 Fit | No Missing, VertexP4 Fit |
|---|---|---|---|---|---|---|
| No CKOV | 0.00106212 | 0.00136379 | 0.0250697 | 0.0135034 | 0.187311 | 0.15011 |
| He DC K: Inclusive |
0.00117589 | 0.00153125 | 0.0365619 | 0.0171601 | 0.244462 | 0.195918 |
| Gas Threshold K: Inclusive |
0.00109474 | 0.00140526 | 0.0343859 | 0.0150712 | 0.244462 | 0.196227 |
| HBRICH K: Inclusive |
0.00126519 | 0.00166155 | 0.0585217 | 0.0309852 | 0.241674 | 0.193994 |
| LHCb RICH K: Inclusive |
0.00121623 | 0.00160001 | 0.0530719 | 0.0247906 | 0.241922 | 0.194071 |
| He DC K: 1 Exclusive |
0.00312333 | 0.00395292 | 0.0658157 | 0.0337837 | 0.29205 | 0.234552 |
| Gas Threshold K: 1 Exclusive |
0.00343035 | 0.00432616 | 0.0813565 | 0.0311833 | 0.242817 | 0.19511 |
| HBRICH K: 1 Exclusive |
0.00397305 | 0.00518064 | 0.104682 | 0.0524333 | 0.238579 | 0.191537 |
| LHCb RICH K: 1 Exclusive |
0.00385906 | 0.00495419 | 0.105741 | 0.0427721 | 0.24112 | 0.193564 |
Signal / Background Ratios : Improvements Over No CKOV
- Detector Signal / Background Ratio (StBR) DIVIDED BY No CKOV StBR
| Detector / PID Cut | Missing p, No Fit | Missing p, P4 Fit | Missing p, VertexP4 Fit | No Missing, No Fit | No Missing, P4 Fit | No Missing, VertexP4 Fit |
|---|---|---|---|---|---|---|
| He DC K: Inclusive |
1.10711 | 1.1228 | 1.45841 | 1.2708 | 1.30511 | 1.30516 |
| Gas Threshold K: Inclusive |
1.03071 | 1.03041 | 1.37161 | 1.11611 | 1.30511 | 1.30722 |
| HBRICH K: Inclusive |
1.19119 | 1.21834 | 2.33436 | 2.29462 | 1.29023 | 1.29235 |
| LHCb RICH K: Inclusive |
1.14509 | 1.17321 | 2.11697 | 1.83588 | 1.29155 | 1.29286 |
| He DC K: 1 Exclusive |
2.94065 | 2.89849 | 2.6253 | 2.50187 | 1.55917 | 1.56253 |
| Gas Threshold K: 1 Exclusive |
3.22971 | 3.17217 | 3.24521 | 2.30929 | 1.29633 | 1.29978 |
| HBRICH K: 1 Exclusive |
3.74067 | 3.79871 | 4.17563 | 3.88297 | 1.2737 | 1.27598 |
| LHCb RICH K: 1 Exclusive |
3.63334 | 3.63267 | 4.21788 | 3.16751 | 1.28727 | 1.28949 |
