2014/07/16 by Bernd Surrow, Surrow, Bernd
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #hep-ex
paper · pdf · doi:10.48550/arxiv.1407.4176
6 pages, 6 figures, Presentation at XXII. International Workshop on Deep-Inelastic Scattering and Related Subjects, 28 April - 2 May 2014, Warsaw, Poland
arxiv created 2014/07/16 · arxiv updated 2014/07/17
One of the main objectives of the high-energy spin physics program at RHIC at BNL is the precise determination of the polarized gluon distribution function, Δg(x). Polarized p+p collisions at √(s)=200 GeV and at √(s)=500 GeV at RHIC provide an unique way to probe the proton spin structure. Inclusive measurements, such as inclusive jet and hadron production, have so far been the prime focus of various results at √(s)=200 GeV constraining Δg(x) for 0.05<x<0.2. A recent global analysis provides for the first time evidence of a non-zero value of the gluon polarization ∫\tiny 0.05\tiny 1Δg (x) dx (Q2=10 \rm GeV2) = 0.20+0.06-0.07. First results of di-jet production at √(s)=200 GeV by the STAR collaboration will allow a better constraint of the underlying event kinematics. Extending the current program to smaller values of x is a key goal for the future high-energy spin physics program at RHIC. Forward di-jet production measurements at STAR beyond the current acceptance from -1<η<+2 to +2.5<η<+4, in particular those carried out at √(s)=500 GeV, provides access to low x values at the level of 10-3 where current uncertainties of Δg(x) remain very large. Those measurements will eventually be complemented by a future Electron-Ion Collider facility probing Δg(x) in polarized e+p collisions.