A new approach to parton-density evolution

Goshtasbpour, Mehrdad; Ratcliffe, Philip G.
June 2001
AIP Conference Proceedings;2001, Vol. 570 Issue 1, p879
Academic Journal
Polarized p-p collisions at RHIC with 50<√s<500 GeV will provide us new information on the spin structure of the nucleon. Using the PHENIX detector, we plan to measure the double-longitudinal spin asymmetry (A[sub LL]) for the heavy-flavor production which is sensitive to the gluon polarization (ΔG(x)) in the proton. We can measure A[sub LL] for J/ψ's, identified with unlike-sign dimuon pairs, with a small experimental uncertainty (δA[sub LL]∼0.006 with 320pb[sup -1] luminosity and √s=200GeV). With the production mechanism of J/ψ understood, ΔG(x) can be extracted from A[sub LL]. Open heavy quarks can be identified with electron-muon pairs whose invariant mass is over 2 GeV/c² with a small background. Using both unlike-sign and like-sign pairs, we can obtain A[sub LL] for both charm and bottom events separately, which constrain ΔG(x).


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