Energy loss of charm quarks from J/ψ production in cold nuclear matter  

作　　者：宋丽华 苗文丹 段春贵 

机构地区：[1]College of Science,Hebei United University [2]Department of Physics,Hebei Normal University [3]Hebei Advanced Thin Films Laboratory

出　　处：《Chinese Physics C》2014年第12期28-32,共5页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(11075044,11347107);Natural Science Foundation of Hebei Province(A2013209299)

摘　　要：J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for J/ψproduction cross-section ratios RW/Be（x F） are presented and compared with the selected E866 experimental data with the cc remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed J/ψ suppression in the experimental data. It is found that the J/ψ suppression on RW/Be（x F） from the initial state nuclear effects is more important than that induced by the energy loss of color octet cc in the large x F region. Whether the cc pair energy loss is linear or quadratic with the path length is not determined. The obtained cc pair energy loss per unit path length α = 2.78±0.81 Ge V/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for J/ψproduction cross-section ratios RW/Be（x F） are presented and compared with the selected E866 experimental data with the cc remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed J/ψ suppression in the experimental data. It is found that the J/ψ suppression on RW/Be（x F） from the initial state nuclear effects is more important than that induced by the energy loss of color octet cc in the large x F region. Whether the cc pair energy loss is linear or quadratic with the path length is not determined. The obtained cc pair energy loss per unit path length α = 2.78±0.81 Ge V/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.

关 键 词：J/ψ production charm quark energy loss 

分 类 号：O572.33[理学—粒子物理与原子核物理]