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For Production in polarized at PHENIX

For Production in polarized at PHENIX. A Weak Interaction Probe at Forward Rapidity. Daniel Jumper University of Illinois at Urbana-Champaign PHENIX Collaboration 4 th Joint APS DNP and JPS Meeting October 9, 2014. Outline. Introduction to Proton Spin

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For Production in polarized at PHENIX

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  1. For Production in polarized at PHENIX A Weak Interaction Probe at Forward Rapidity Daniel Jumper University of Illinois at Urbana-Champaign PHENIX Collaboration 4th Joint APS DNP and JPS Meeting October 9, 2014

  2. Outline • Introduction to Proton Spin • Sea quark spin with the weak interaction • RHIC Polarized • Forward at PHENIX • Results and Prospects Daniel Jumper

  3. Proton Spin • Proton Spin Decomposition: • for • – Gluon spin • orbital angular momentum • Current Understanding • DIS/SIDIS • , some • RHIC • , Daniel Jumper

  4. Weak Probe for Sea Quark Spin • More clean and direct access with the weak interaction • No fragmentation functions • High • Constraints: • Weak parity violation • ’s couple to left handed and right handed • Known spin distributions • spin tends to be aligned with proton spin, anti-aligned Daniel Jumper

  5. at Forward Rapidity Proton Constituent Probability Distributions • A first order motivation: • At forward rapidity or • equations reduce: • It’s not actually this simple! • is measured, not • Measured asymmetries used in global fit to extract pdf’s accounting for higher order effects Daniel Jumper

  6. Spin at RHIC • at up to 60% polarization • “Siberian Snake” Spin Rotators Daniel Jumper

  7. Recent Runs • Up to 510 GeV • High polarization is important for figure of merit Daniel Jumper

  8. Forward at PHENIX • events are rare at large rapidity • Forward Arms: Trigger and tracking systems targeting these muons (~1.2-2.4) • Upgraded highly selective trigger • Developed over the past decade • JSPS and NSF funding Daniel Jumper

  9. Forward at Phenix • Signal events dominated by other processes • Other sources of muons, “Fake” muons from hadronic decay • Made worse by smearing in tracking detectors Process cross sections vs from simulations Muonic Signal and Background contributions Also Hadronic “Fake” Muon Background Contribution Including Smearing Daniel Jumper

  10. Analysis Technique • Multivariate analysis technique: Likelihood Ratio • Apply a cut to select data with higher relative signal content • Characterize signal/background ratio of remaining data • Count of remaining data, correct by sig/bkg, efficiencies, polarization . . . Likelihood Ratio Daniel Jumper

  11. Results and Prospect • 2012preliminary Results • 53 • Projected2013Results • Projected error for 200 • Actual data taken: • 277 • Analysis well underway, preliminary results soon! Daniel Jumper

  12. Conclusion • Forward asymmetry gives insight to • Extracting this signal is experimentally challenging • Pending results from PHENIX will contribute to a better understanding of sea quark spin DSSV projected impact of PHENIX and STAR results for Daniel Jumper

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