Difference between revisions of "Mattione Update 07092012"
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! π<sup>+</sup> | ! π<sup>+</sup> |
Revision as of 21:57, 8 July 2012
Contents
Y(2175) Study
Reaction
- γ p → Y(2175), p
- Y(2175) → π+, π-, φ
- φ → K+, K-
- Y(2175) → π+, π-, φ
- Final State: p, π+, π-, K+, K-
- ~530,000 Events Generated using genr8 with: 9 GeV Photons, ΓY(2175) = 61 MeV/c2, t-slope = 5.0, 50.0 < Vertex-Z (cm) < 80.0
Background Channel
- γ p → f1(1285), p
- f1(1285) → π+, π-, π+, π-
- NOTE: had to trick genr8 by having the f1(1285) decay to η, η, and then each decaying to π+, π-
- Final State: p, π+, π-, π+, π-
- ~530,000 Events Generated using genr8 with: 9 GeV Photons, Γf1(1285) = 24 MeV/c2, t-slope = 5.0, 50.0 < Vertex-Z (cm) < 80.0
Pythia
- Generated entire photon energy region
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!)
- 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 reconstruction of 2-to-3 + Tracks, 2 - Tracks (proton is treated as missing)
- Required 45.0 < Track-Vertex-Z (cm) < 85.0
- Required DOCA between tracks < 5.0 cm
- Require the combined FOM for PID (π+, π-, K+, K-) be > 1%
- Place very loose cuts on the φ invariant mass (0.8 - 1.3) and p missing mass (0.5 - 1.4): reduces # of bogus track combinations to save time / cleanup histograms
- Phi mass cut: 1.004 < K+K- Invariant Mass (GeV/c2) < 1.04
- Kinematic Fit: 4-momentum conservation: p missing mass
- Require that the confidence level from the kinematic fit be > 1%
Thrown Track Parameters
- Thrown Track Parameters
Track | Y(2175) | f1(1285) | Pythia |
---|---|---|---|
γ | |||
K+ | NA | ||
K- | NA | ||
π+ | |||
π- | |||
p |
Initial Mass Peaks
- Initial Mass Peaks
Mass Peak | Y(2175) | f1(1285) | Pythia |
---|---|---|---|
φ | |||
p | |||
Y(2175) |
Kinematic Fitting
- Confidence Level
Fit Constraint | Y(2175) | f1(1285) | Pythia |
---|---|---|---|
(p) |
Final Mass Peaks
- Final Mass Peaks
- NOTE: proton peak uses pre-kinfit track momentum, Y(2175) peak uses post-kinfit track momentum
Mass Peak | Y(2175) | f1(1285) | Pythia |
---|---|---|---|
p | |||
Y(2175) |