Mattione Kaon PID Studies phi3(1850)
From GlueXWiki
Contents
Reaction
- γ p → φ3(1850), p
- φ3(1850) → K+, K-
- Final State: p, K+, K-
- Events generated with: Γφ3(1850) = 87 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
genr8 φ3(1850) Signal
- 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
| Plot | genr8 Signal | genr8 Background | bggen Background |
|---|---|---|---|
| Confidence Level |  |
 |
 |
| Missing Mass |  |
 |
 |
| φ3(1850) Mass |  |
 |
 |
- Missing Mass & Missing Mass Squared (Before/after KinFit where present)
| Recoil p | No KinFit | P4 KinFit | VertexP4 KinFit |
|---|---|---|---|
| Missing | | ||
| Not Missing |
- φ3(1850) Invariant Mass (Before/after KinFit where present)
| Recoil p | No KinFit | P4 KinFit | VertexP4 KinFit |
|---|---|---|---|
| Missing | | ||
| Not Missing |  |
genr8 φ3(1850) Background
- Generate pions instead of kaons, shift generated mass peaks so that when the kaon mass is assigned to the kaon candidates (pions), the mass peaks shift to the original signal masses.
- Note that it is impossible to get every peak to line up without generated a recoil proton with a bogus mass. Therefore, the missing mass peak is slightly off.
- Missing Mass & Missing Mass Squared (Before/after KinFit where present)
| Recoil p | No KinFit | P4 KinFit | VertexP4 KinFit |
|---|---|---|---|
| Missing | |||
| Not Missing |
- φ3(1850) Invariant Mass (Before/after KinFit where present)
| Recoil p | No KinFit | P4 KinFit | VertexP4 KinFit |
|---|---|---|---|
| Missing | |||
| Not Missing |
bggen Background
- φ3(1850) Invariant Mass (Before/after KinFit where present)
- The other mass peaks are cut (when not KinFit), but aren't shown here.
| Recoil p | No KinFit | P4 KinFit | VertexP4 KinFit |
|---|---|---|---|
| Missing | | ||
| Not Missing |  |
Cherenkov Detector Comparison: genr8 φ3(1850) 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.
Cherenkov Detector Comparison: 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.
Yields %'s
- ALL yield %'s are determined in the signal region (track combinations with invariant mass outside of the signal region are ignored)
genr8 φ3(1850) Signal Events
- % of generated events remaining after all cuts (including a final cut requiring that all tracks have the correct THROWN PID)
| Missing p, No KinFit | Missing p, P4 KinFit | Missing p, VertexP4 KinFit | No Missing, No KinFit | No Missing, P4 KinFit | No Missing, VertexP4 KinFit |
|---|---|---|---|---|---|
| a% | b% | c% | d% | e% | f% |
- % of BAD reconstructed combos remaining (BAD combo: a combo where at least one track has the wrong THROWN PID)
| Stage | Missing p, No KinFit | Missing p, P4 KinFit | Missing p, VertexP4 KinFit | No Missing, No KinFit | No Missing, P4 KinFit | No Missing, VertexP4 KinFit |
|---|---|---|---|---|---|---|
| w/o CKOV | a% | b% | c% | d% | e% | f% |
| He DC | a% | b% | c% | d% | e% | f% |
| Gas Thresh. | a% | b% | c% | d% | e% | f% |
| RICH (Yi) | a% | b% | c% | d% | e% | f% |
| LHCb RICH | a% | b% | c% | d% | e% | f% |
genr8 φ3(1850) Background Events
- % of reconstructed combos remaining
| Stage | Missing p, No KinFit | Missing p, P4 KinFit | Missing p, VertexP4 KinFit | No Missing, No KinFit | No Missing, P4 KinFit | No Missing, VertexP4 KinFit |
|---|---|---|---|---|---|---|
| w/o CKOV | a% | b% | c% | d% | e% | f% |
| He DC | a% | b% | c% | d% | e% | f% |
| Gas Thresh. | a% | b% | c% | d% | e% | f% |
| RICH (Yi) | a% | b% | c% | d% | e% | f% |
| LHCb RICH | a% | b% | c% | d% | e% | f% |
bggen Background Events
- % of reconstructed combos remaining
| Stage | Missing p, No KinFit | Missing p, P4 KinFit | Missing p, VertexP4 KinFit | No Missing, No KinFit | No Missing, P4 KinFit | No Missing, VertexP4 KinFit |
|---|---|---|---|---|---|---|
| w/o CKOV | a% | b% | c% | d% | e% | f% |
| He DC | a% | b% | c% | d% | e% | f% |
| Gas Thresh. | a% | b% | c% | d% | e% | f% |
| RICH (Yi) | a% | b% | c% | d% | e% | f% |
| LHCb RICH | a% | b% | c% | d% | e% | f% |
