Radphi Analysis at I'U'

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Radphi Analysis at I.U.
Dan Krop 9/06/02
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Overview

• BGV Callibration
• Using Gradphi Monte Carlo
• PWA Formalism for Spin 1 Beam
• Moments of the Angular Distribution
• Future Prospects

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Goals of Analysis

• Radphi Has Largest Sample of Photoproduced p0p0
  in the World
• Large Sample Allows For Quality Measurement of
  f0(980) Phase Shift

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BGV Calibration Overview

• Calibrating BGV To Use As Veto Only
• 2 Kinds of Calibration
• Timing w/ Respect to Tagger
• BSD Overlay of Recoil Proton
• Timing Requires New Map Entries
• BSD Overlay is Simple Clock Function

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BGV Timing Calibration

• Timing Distributions (TDC-Tagger) Fit to
  Gaussians and Means Extracted
• Means Used to Create New Map Entries for Upstream
  and Downstream TDC
• Corrected Distributions Show a Range of 15-20 ns
  Around 0

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BGV Channel vs. (ttagger-tTDC)
Run 7948
Uncorrected
Corrected
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BGV Time Difference

• With Offsets Applied
• For Upstream Channel 4 in Run 7948
• 15-20 ns Timing Window

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Gradphi Monte Carlo Studies

• Had 111,823 p0p0 Events in Data
• Want to Have 10xData in Accepted MC
• Generated 4g Events Flat in Mass From Threshold
  to 1.5 GeV w/ a6.4
• Simulated All Data Cuts (except BGV)
• 97.2 M Events Generated
• 1.13 M Events Accepted

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Monte Carlo Acceptance

• 1.5 M Events Generated
• GEO Trigger (pre-processing) Not Used in Big MC
  Run
• Greatest Loss Through Strict Photon Energy Cut
  (gt5 GeV)
• Hypothesis Sorting Only Fails 6
• Acceptance w/o GEO was 1.16

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Invariant Mass
97.2 M Generated MC Events
Uncorrected Mass Distribution
Acceptance Corrected Distribution
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Momentum Transfer
-t1lt.10 GeV2 .10lt-t2lt.020
GeV2 .20lt-t3lt1.50 GeV2 .40lt-t4lt1.50 GeV2
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PWA Formalism

• In Case of Spinless Beam (e.g. p,K) m0,1 in PWA
• Baryon Helicity Can Impart At Most m1 to Meson
  Resonance
• In Photoproduction m2 Can Contribute
• New Convention For Wave Amplitudes Needed

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Reflectivity Basis

• Basis For the Amplitudes That Has the Following
  Properties
• 2 eigenvalues for operator e1,-1
• D functions real for e-1, imaginary for e1
• Eigenvalue coincides with naturality of exchanged
  particle in gp Xp

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PWA Conventions

• Amplitude in Reflectivity Basis Can Be Written
• eU(W)SeVl meAl m(W)
• Convention w/ m2 included
• l0(-)Vl 0 l1-(-)Vl 1
  l2-(-)Vl 2
• l1()Vl 1 l2()Vl 2

• Vproduction amp., Adecay amp.,
  ereflectivity

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Moments
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Prospects and Outlook

• Object-Orienting and ROOT-ifying PWA Code of M.
  Swat (E852)
• Expect Completion By End of 2002
• After p0p0 PWA is Completed, Can Look at hp to
  Verify FSI Effects Seen in E852
• FSI should be same as from spinless beam
• Exotic production should be enhanced