An improved global analysis of nuclear parton distribution functions including RHIC data
Abstract
We present an improved leading-order global DGLAP analysis of nuclear parton distribution functions (nPDFs), supplementing the traditionally used data from deep inelastic lepton-nucleus scattering and Drell-Yan dilepton production in proton-nucleus collisions, with inclusive high- hadron production data measured at RHIC in d+Au collisions. With the help of an extended definition of the function, we now can more efficiently exploit the constraints the different data sets offer, for gluon shadowing in particular, and account for the overall data normalization uncertainties during the automated minimization. The very good simultaneous fit to the nuclear hard process data used demonstrates the feasibility of a universal set of nPDFs, but also limitations become visible. The high- forward-rapidity hadron data of BRAHMS add a new crucial constraint into the analysis by offering a direct probe for the nuclear gluon distributions -- a sector in the nPDFs which has traditionally been very badly constrained. We obtain a strikingly stronger gluon shadowing than what has been estimated in previous global analyses. The obtained nPDFs are released as a parametrization called EPS08.
Cite
@article{arxiv.0802.0139,
title = {An improved global analysis of nuclear parton distribution functions including RHIC data},
author = {K. J. Eskola and H. Paukkunen and C. A. Salgado},
journal= {arXiv preprint arXiv:0802.0139},
year = {2010}
}
Comments
26 pages, 14 figures; for v2, we have revised the Table 1 and Fig. 13, and added the Fig. 14 and the Table 3 along with some more discussion