Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8182706 | Nuclear Physics A | 2018 | 19 Pages |
Abstract
The nuclear modification factor RpA(pT) provides information on the small-x gluon distribution of a nucleus at hadron colliders. Several experiments have recently measured the nuclear modification factor not only in minimum bias but also for central pA collisions. In this paper we analyze the bias on the configurations of soft gluon fields introduced by a centrality selection via the number of hard particles. Such bias can be viewed as reweighting of configurations of small-x gluons. We find that the biased nuclear modification factor QpA(pT) for central collisions is above RpA(pT) for minimum bias events, and that it may redevelop a “Cronin peak” even at small x. The magnitude of the peak is predicted to increase approximately like 1/Aâ¥Î½, νâ¼0.6±0.1, if one is able to select more compact configurations of the projectile proton where its gluons occupy a smaller transverse area Aâ¥. We predict an enhanced Qpp(pT)â1â¼1/(pT2)ν and a Cronin peak even for central pp collisions.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Nuclear and High Energy Physics
Authors
Adrian Dumitru, Gary Kapilevich, Vladimir Skokov,