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 00 in the World Large Sample Allows For Quality

Measurement of f0(980) Phase Shift

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

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

BGV Channel vs. (ttagger-tTDC)

Uncorrected

Corrected

Run 7948

BGV Time Difference

•With Offsets Applied

•For Upstream Channel 4 in Run 7948

• 15-20 ns Timing Window

Gradphi Monte Carlo Studies Had 111,823 Events in Data Want to Have 10xData in Accepted

MC Generated 4 Events Flat in Mass

From Threshold to 1.5 GeV w/ =6.4 Simulated All Data Cuts (except BGV) 97.2 M Events Generated 1.13 M Events Accepted

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%

Invariant Mass

Uncorrected Mass Distribution Acceptance Corrected Distribution

97.2 M Generated MC Events

Momentum Transfer

-t1<.10 GeV2 .10<-t2<.020 GeV2

.20<-t3<1.50 GeV2 .40<-t4<1.50 GeV2

PWA Formalism In Case of Spinless Beam (e.g.

,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

Reflectivity Basis

Basis For the Amplitudes That Has the Following Properties:

2 eigenvalues for operator: =+1,-1 D functions real for =-1, imaginary

for =+1 Eigenvalue coincides with naturality

of exchanged particle in p Xp

PWA Conventions

Amplitude in Reflectivity Basis Can Be Written

U()=Vl mAl m()

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., =reflectivity

Moments

)0,,()()( 0 LMDIdLMH

Prospects and Outlook Object-Orienting and ROOT-ifying PWA

Code of M. Swat (E852) Expect Completion By End of 2002 After 00 PWA is Completed, Can Look

at to Verify FSI Effects Seen in E852 FSI should be same as from spinless beam Exotic production should be enhanced