Quarkonium Polarization Fit: Applied to one p T bin in CDF data

1. Quarkonium Polarization Fit:Applied to one pT bin in CDF data Matthew Jones Purdue University B Production and Decay Meeting

2. Recent Progress • CMP efficiency measured using J/ψ sample • Subdivisions of data • Checking goodness of fit • Relieving tension in the fit B Production and Decay Meeting

3. CMP Efficiency • Generic muon sample in UPSILON trigger paths contains a significant fake contribution • Background is certainly not pure Drell-Yan • Can’t be used to study CMP efficiency • Also potentially biased by CMP trigger • Use the fitted J/ψ yields to measure CMP efficiency directly using the jpmm0* data sets. B Production and Decay Meeting

4. CMP Efficiency • Typical example: • Drop in efficiency near z=0 most pronounced in the background. • Efficiency is generally flat as a function of z • But measured separately for east and west ends of the chambers. • Fitted as a function of 1/pT Denominator Numerator B Production and Decay Meeting

5. CMP Efficiency • Functional form: • Linear term needed in some cases. • We only care about 1/pT below about 1/(2.5 GeV/c). B Production and Decay Meeting

6. Yields in different parts of CDF • Looking for asymmetries not modeled in the Monte Carlo • Obviously the yields in CMUP+CMU and CMUP+CMX are different – correct for calculated (un-polarized) acceptanceand relative integrated luminosity B Production and Decay Meeting

7. Yields in different parts of CDF • Acceptance corrected yield comparison: • Observe a 10-20% difference in CMUP+CMU and CMUP+CMX trigger paths; • probably can’t constrain these cross sections to be equal in the fit. B Production and Decay Meeting

8. Time dependence of “cross section” • Subdivide data into 10 ranges with approximately equal DFC luminosity: • Calculate cross section using un-polarized acceptance from corresponding run range. B Production and Decay Meeting

9. Time dependence of “cross section” • There appears to be some time dependence • Bigger effect for CMX? • Alternate explanation might be biases in fits due to changing background shape • Need to check cross sections in different wedges? • Re-scale efficiency to account for relative geometric efficiency? B Production and Decay Meeting

10. Polarization fit Background mass bins ϒ(3S) ϒ(2S) ϒ(1S) S-channel helicity Collins-Soper B Production and Decay Meeting

11. But the fit is still petulant… ϒ(1S) Description in CMX is poor in some mass bins ϒ(2S) Cos θ distributions, Collins-Soper frame, |y|<0.6 ϒ(3S) B Production and Decay Meeting

12. But the fit is still petulant… ϒ(1S) Background in some bins appears more transversely polarized than the fit will accommodate. ϒ(2S) Cos θ distributions, S-channel helicity frame, |y|<0.6 ϒ(3S) B Production and Decay Meeting

13. Next steps • Add parameters to the model: • “cross section” of background is not quite linear; add a quadratic term • Polarization of background may be mass dependent • Compare quality of fit (Δlog L) to establish statistical need for additional parameters. • Compute of projections to quantify tension in different mass bins. • Then re-visit dicing up sample into E/W, N/S, T/B to test for consistency. B Production and Decay Meeting