Particle Physics Seminar

"Understanding Hard Interactions in QCD and the Search for the Gluon Spin Contribution to the Spin of the Proton."

Presented by Amaresh Datta, University of Massachusetts, Amherst

Monday, November 28, 2011, 3:00 pm — Small Seminar Room, Bldg. 510

We investigate hard interaction in QCD through the measurement of cross sections of mid-rapidity production of non-identified charged hadrons from $p+p$ collisions at $\sqrt{s} = 62.4$ GeV/$c$. Measurements are made in the transverse momentum range from 0.5 GeV/$c$ to 4.5 GeV/$c$ by the PHENIX collaboration at RHIC. The cross section results are consistent with predictions based on QCD calculations of next-to-leading order (NLO) accuracy and shows better agreement with next-to-leading log QCD predictions. The double helicity asymmetry measurements of mid-rapidity non-identified charged hadrons in the stipulated transverse momentum range are sensitive at leading order to the polarization of gluons in a momentum fraction range $0.06 \leq x_{gluon} \leq 0.3$. Asymmetry measurements are consistent with zero and disfavor a large gluon polarization in the proton.

Hosted by: David Jaffe

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