Difference between revisions of "Mattione Kaon PID Studies Y2175"

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Revision as of 21:49, 14 September 2012

Reaction

  • γ p → Y(2175), p
    • Y(2175) → π+, π-, φ
      • φ → K+, K-
  • 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

genr8 Y(2175) Signal

  • Kinematic Fit Confidence Level (Zoomed in; spike at 0 confidence is well off the top of the plot)
    • NOTE: φ mass is not constrained by kinematic fit.
Recoil p P4 KinFit VertexP4 KinFit
Missing
350px
Mattione Update 09132012 KinFitConLev MissingP VertexP4KinFit Y2175.png
Not Missing
350px
350px


  • φ Invariant Mass (Before/after KinFit where present)
    • NOTE: φ mass is not constrained by kinematic fit.
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 PhiMass MissingP VertexP4KinFit Y2175.png
Not Missing
350px
350px
350px


  • Missing Mass & Missing Mass Squared (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 MissingMass MissingP VertexP4KinFit Y2175.png
Not Missing
350px
350px
350px


  • Y(2175) Invariant Mass (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 Y2175Mass MissingP VertexP4KinFit Y2175.png
Not Missing
350px
350px
350px


genr8 Y(2175) 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.
  • φ Invariant Mass (Before/after KinFit where present)
    • NOTE: φ mass is not constrained by kinematic fit.
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
350px
Not Missing
350px
350px
350px


  • Missing Mass & Missing Mass Squared (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
350px
Not Missing
350px
350px
350px


  • Y(2175) Invariant Mass (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
350px
Not Missing
350px
350px
350px


bggen Background

  • φ Invariant Mass (Before/after KinFit where present)
    • NOTE: φ mass is not constrained by kinematic fit.
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 PhiMass MissingP VertexP4KinFit Y2175bggen.png
Not Missing
350px
350px
350px


  • Missing Mass & Missing Mass Squared (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 MissingMass MissingP VertexP4KinFit Y2175bggen.png
Not Missing
350px
350px
350px


  • Y(2175) Invariant Mass (Before/after KinFit where present)
Recoil p No KinFit P4 KinFit VertexP4 KinFit
Missing
350px
350px
Mattione Update 09132012 Y2175Mass MissingP VertexP4KinFit Y2175bggen.png
Not Missing
350px
350px
350px


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.
π+ as K+ No Missing, P4 KinFit No Missing, VertexP4 KinFit p Missing, P4 KinFit p Missing, VertexP4 KinFit
All
350px
Mattione Update 09132012 PVsTheta PiPlusPassKPlus All MissingP VertexP4KinFit Y2175bkgnd.png
350px
350px
He DC
350px
350px
350px
350px
Gas Thresh.
350px
350px
350px
350px
RICH (Yi)
350px
350px
350px
350px
LHCb RICH
350px
350px
350px
350px


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.
π+ as K+ No Missing, P4 KinFit No Missing, VertexP4 KinFit p Missing, P4 KinFit p Missing, VertexP4 KinFit
All
350px
Mattione Update 09132012 PVsTheta PiPlusPassKPlus All MissingP VertexP4KinFit Y2175bggen.png
350px
350px
He DC
350px
350px
350px
350px
Gas Thresh.
350px
350px
350px
350px
RICH (Yi)
350px
350px
350px
350px
LHCb RICH
350px
350px
350px
350px


Yields %'s

  • ALL yield %'s are determined in the signal region (track combinations with invariant mass outside of the signal region are ignored)

genr8 Y(2175) 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 Y(2175) 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%


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