Mattione Update 06252012

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Reaction

  • γ p → Y(2175), p
    • Y(2175) → π+, π-, φ
      • φ → K+, K-
  • 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
Mattione Update 06252012 ThrownPVsTheta KPlus.png
Mattione Update 06252012 ThrownPVsTheta KMinus.png
Mattione Update 06252012 ThrownPVsTheta PiPlus.png
Mattione Update 06252012 ThrownPVsTheta PiMinus.png
Mattione Update 06252012 ThrownPVsTheta Proton.png


PID

  • PID FOM
Mattione Update 06252012 PIDFOM KPlus.png
Mattione Update 06252012 PIDFOM KMinus.png
Mattione Update 06252012 PIDFOM PiPlus.png
Mattione Update 06252012 PIDFOM PiMinus.png


Initial Mass Peaks

  • Initial Mass Peaks
φ Invariant Mass
Proton Missing Mass
Y(2175) Invariant Mass


Kinematic Fitting Plots

  • Confidence Level
Mattione Update 06252012 ConfidenceLevel.png


  • Confidence Level vs. Mass
Mattione Update 06252012 ConfidenceLevelVsPhiMass.png
Mattione Update 06252012 ConfidenceLevelVsProtonMass.png


  • Pulls (Confidence Level Cut at 10% for histogramming)
    • μ's = ~0.0, σ's = ~1.08
Track px Pull py Pull pz Pull
γ
Mattione Update 06252012 Pull PhotonPz.png
K+
Mattione Update 06252012 Pull KPlusPx.png
Mattione Update 06252012 Pull KPlusPy.png
Mattione Update 06252012 Pull KPlusPz.png
K-
Mattione Update 06252012 Pull KMinusPx.png
Mattione Update 06252012 Pull KMinusPy.png
Mattione Update 06252012 Pull KMinusPz.png
π+
Mattione Update 06252012 Pull PiPlusPx.png
Mattione Update 06252012 Pull PiPlusPy.png
Mattione Update 06252012 Pull PiPlusPz.png
π-
Mattione Update 06252012 Pull PiMinusPx.png
Mattione Update 06252012 Pull PiMinusPy.png
Mattione Update 06252012 Pull PiMinusPz.png


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
φ Invariant Mass
Proton Missing Mass
Y(2175) Invariant Mass


Track P & PID Fraction vs. p

  • Track P & PID Fraction vs. p
Track Thrown Track p Final Track p PID % vs p
K+
Mattione Update 06252012 ThrownP KPlus.png
Mattione Update 06252012 ComboP KPlus.png
Mattione Update 06252012 PIDFractionVsP KPlus.png
K-
Mattione Update 06252012 ThrownP KMinus.png
Mattione Update 06252012 ComboP KMinus.png
Mattione Update 06252012 PIDFractionVsP KMinus.png
π+
Mattione Update 06252012 ThrownP PiPlus.png
Mattione Update 06252012 ComboP PiPlus.png
Mattione Update 06252012 PIDFractionVsP PiPlus.png
π-
Mattione Update 06252012 ThrownP PiMinus.png
Mattione Update 06252012 ComboP PiMinus.png
Mattione Update 06252012 PIDFractionVsP PiMinus.png