English

Nuclear dependence coefficient $\alpha(A,q_T)$ for the Drell-Yan and J/$\psi$ production

High Energy Physics - Phenomenology 2009-10-31 v2 Nuclear Theory

Abstract

Define the nuclear dependence coefficient α(A,qT)\alpha(A,q_T) in terms of ratio of transverse momentum spectrum in hadron-nucleus and in hadron-nucleon collisions: dσhAdqT2/dσhNdqT2Aα(A,qT)\frac{d\sigma^{hA}}{dq_T^2}/ \frac{d\sigma^{hN}}{dq_T^2}\equiv A^{\alpha(A,q_T)}. We argue that in small qTq_T region, the α(A,qT)\alpha(A,q_T) for the Drell-Yan and J/ψ\psi production is given by a universal function:\ a+bqT2a+b q_T^2, where parameters a and b are completely determined by either calculable quantities or independently measurable physical observables. We demonstrate that this universal function α(A,qT)\alpha(A,q_T) is insensitive to the A for normal nuclear targets. For a color deconfined nuclear medium, the α(A,qT)\alpha(A,q_T) becomes strongly dependent on the A. We also show that our α(A,qT)\alpha(A,q_T) for the Drell-Yan process is naturally linked to perturbatively calculated α(A,qT)\alpha(A,q_T) at large qTq_T without any free parameters, and the α(A,qT)\alpha(A,q_T) is consistent with E772 data for all qTq_T.

Keywords

Cite

@article{arxiv.hep-ph/9912361,
  title  = {Nuclear dependence coefficient $\alpha(A,q_T)$ for the Drell-Yan and J/$\psi$ production},
  author = {Xiaofeng Guo and Jianwei Qiu and Xiaofei Zhang},
  journal= {arXiv preprint arXiv:hep-ph/9912361},
  year   = {2009}
}

Comments

latex, 28 pages, 10 figures, updated two figures, and add more discussions