Within a generalized parton model approach, with inclusion of spin and intrinsic transverse momentum effects, we show how the latest, highly precise, midrapidity data on the transverse single spin asymmetry measured in pp→π0X by the PHENIX Collaboration at RHIC [1], can be used to get a first estimate on the still poorly known gluon Sivers distribution. To this end we also adopt the present information on the quark Sivers functions, as extracted from semi-inclusive deeply inelastic scattering data. This analysis updates a previous study by some of us where a first bound on this distribution was obtained [2].
@article{arxiv.1506.03078,
title = {Towards a first estimate of the gluon Sivers function from $A_N$ data in $pp$ collisions at RHIC},
author = {U. D'Alesio and F. Murgia and C. Pisano},
journal= {arXiv preprint arXiv:1506.03078},
year = {2015}
}
Comments
RevTex4, 10 pages, 7 eps figures. V2: discussion on the process dependence of the quark Sivers function, with two new plots (Fig. 4), added in Section II. One reference added. Results unchanged. Matches the published version