Difference between revisions of "Mattione Update 06252012"
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*** φ → K<sup>+</sup>, K<sup>-</sup> | *** φ → K<sup>+</sup>, K<sup>-</sup> | ||
* Final State: p, π<sup>+</sup>, π<sup>-</sup>, K<sup>+</sup>, K<sup>-</sup> | * Final State: p, π<sup>+</sup>, π<sup>-</sup>, K<sup>+</sup>, K<sup>-</sup> | ||
− | * Events Generated using genr8 with: 9 GeV Photons, Γ<sub>Y(2175)</sub> = 61 MeV/c<sup>2</sup>, t-slope = 5.0, 50.0 < Vertex-Z (cm) < 80.0 | + | * ~530,000 Events Generated using genr8 with: 9 GeV Photons, Γ<sub>Y(2175)</sub> = 61 MeV/c<sup>2</sup>, t-slope = 5.0, 50.0 < Vertex-Z (cm) < 80.0 |
* No background generated (all background is from combinatorics) | * No background generated (all background is from combinatorics) | ||
Latest revision as of 14:21, 25 June 2012
Contents
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
- No background generated (all background is from combinatorics)
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):
- Require the detection of at least 2+ and 2- tracks (proton is treated as missing)
- 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
- Kinematic Fit: 4-momentum conservation: p missing mass, φ invariant mass
- Require that the confidence level from the kinematic fit be > 1%
Thrown Track Parameters
- p vs θ
PID
- PID FOM
Initial Mass Peaks
- Initial Mass Peaks
Kinematic Fitting Plots
- Confidence Level
- Confidence Level vs. Mass
- Pulls (Confidence Level Cut at 10% for histogramming)
- μ's = ~0.0, σ's = ~1.08
Track | px Pull | py Pull | pz Pull |
---|---|---|---|
γ | |||
K+ | |||
K- | |||
π+ | |||
π- |
Final Mass Peaks
- Final Mass Peaks
- The Y(2175) Invariant Mass is calculated using the kinematic fit values of the track 3-momenta.
- The Y(2175) Invariant Mass is fit to Breit-Wigner over a quadratic background (I couldn't get the Voigtian fits to converge), and has Γ = ~80 MeV/c2 (as opposed to the generated Γ = 61 MeV/2)
- ~18.9 % of all events remaining
Track P & PID Fraction vs. p
- Track P & PID Fraction vs. p
Track | Thrown Track p | Final Track p | PID % vs p |
---|---|---|---|
K+ | |||
K- | |||
π+ | |||
π- |