QCD Meeting July 1, 2005

QCD Meeting July 1, 2005 Is it due to the hard collision? Is it due to fragmentation ? Strong polarization seen in fixed-target experiments where jet NOT observed. Polarization Tom Devlin Rutgers/CDF _

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_.  Polarization Tom Devlin Rutgers/CDF. Strong polarization seen in fixed-target experiments where jet NOT observed. Is it due to the hard collision?. Is it due to fragmentation?. QCD Meeting July 1, 2005. Status and Plans. Three known contributions to dataset: --  Signal - PowerPoint PPT Presentation

Transcript of QCD Meeting July 1, 2005

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

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?