QCD MeetingJuly 1, 2005

Is it due to the hard collision?

Is it due tofragmentation?

Strong polarization seenin fixed-target experimentswhere jet NOT observed.

PolarizationTom Devlin

Rutgers/CDF

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Status and Plans

Three known contributions to dataset: -- Signal -- Ks Background -- Continuum 2-track background

Previous report: -- From data, measured relative fractions of these as functions of momentum and decay distance.

Run 1 computer – cdfsga – to be shutdown -- Verified that data written by it are correct -- Ran all data through cdfsga, copied to Rutgers -- Thanks to Glenn Cooper and Mike Stolz.

Now working with 100% of data at Rutgers!!! -- Real data look reasonable. -- x20 MC is working to a first approximation.

Reconstruction: p and

Simple cut to elliminate e+e-

For Each Bin in Momentum and Lxy Evaluate Fractions of , Ks and

Background Equations

Restrictions on Angular Distribution

Asymmetry Plots for Data and MC: Beam- System

Asymmetry Plots for Data and MC: Beam-Jet System

Asymmetry Plots for Data and MC: Jet- System

Work in Progress and Planned: 2005

11 Mass-constrained fits: 2-, 2-Ks, 1-ee.11 Sum of weights over solutions = 1.0 per event.11 Use 2 = 2(MassConstraint) - 2(NoMassConstraint)11 Determine relative proportions of , Ks and background5. Modify 2nd stage analysis code to mix MC samples from , Ks, in correct proportions. 6. Finish all work on cdfsga.7. Do polarization study in all three coordinate systems.9. Is polarization analysis believable?