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Radphi Analysis at I.U.

Radphi Analysis at I.U. Dan Krop 9/06/02. Overview. BGV Callibration Using Gradphi Monte Carlo PWA Formalism for Spin 1 Beam Moments of the Angular Distribution Future Prospects. Goals of Analysis. Radphi Has Largest Sample of Photoproduced p 0 p 0 in the World

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Radphi Analysis at I.U.

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

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

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

  4. 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

  5. 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

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

  7. BGV Time Difference • With Offsets Applied • For Upstream Channel 4 in Run 7948 • 15-20 ns Timing Window

  8. 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/ a=6.4 • Simulated All Data Cuts (except BGV) • 97.2 M Events Generated • 1.13 M Events Accepted

  9. 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 (>5 GeV) • Hypothesis Sorting Only Fails 6% • Acceptance w/o GEO was 1.16%

  10. Invariant Mass 97.2 M Generated MC Events Uncorrected Mass Distribution Acceptance Corrected Distribution

  11. Momentum Transfer -t1<.10 GeV2 .10<-t2<.020 GeV2 .20<-t3<1.50 GeV2 .40<-t4<1.50 GeV2

  12. PWA Formalism • In Case of Spinless Beam (e.g. p,K) m=0,1 in PWA • Baryon Helicity Can Impart At Most m=1 to Meson Resonance • In Photoproduction m=2 Can Contribute • New Convention For Wave Amplitudes Needed

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

  14. PWA Conventions Amplitude in Reflectivity Basis Can Be Written eU(W)=SeVl meAl m(W) Convention w/ m=2 included: [l]0=(-)Vl 0 [l]1-=(-)Vl 1 [l]2-=(-)Vl 2 [l]1+=(+)Vl 1 [l]2+=(+)Vl 2 V=production amp., A=decay amp., e=reflectivity

  15. Moments

  16. 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

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