The Quark Transport Coefficient In Proton-Induced Drell-Yan Off Nuclei

The study of the properties of quark-gluon plasmas by the Relativistic Heavy-Ion Collision is an important topic of experimental and theoretical research in intermediate and high energy nuclear physics.The energic partons interact with the medium as they travel through the dense medium formed by the collision,thus losing some of their energy,which is known as"jet quenching".It is one of the criteria to judge the formation of quark-gluon plasma in high-energy nuclear collisions.However,the mechanism of energy loss of parton in the process of nuclear medium is still not fully understood.The Drell-Yan reaction of hadron on nucleus provide an excellent place on the study of the energy loss of the incoming parton in cold nuclear matter.In this paper,the section ratios of proton-nucleus collision in Drell-Yan process are calculated under the perturbation QCD next-leading-order approximation by using the molecular distribution function of nucleus independent of experimental data of fixed-target Drell-Yan process and the parameterized quenching weight based on BDMPS formula.And compared with the experimental data reported by Fermilab E906 and E866 collaboration.It is found that the calculated cross section ratios with only the nuclear effects of parton distribution are not in agreement with the E906 and E866 data.The incoming parton energy loss effect cannot be ignored in the nuclear Drell-Yan reactions.The predicted results indicate that with the quark transport coefficient as a constant,the suppression due to the target nuclear geometry effect is approximately 16.85%for the quark transport coefficient.It is shown that we should consider the target nuclear geometry effect in studying the Drell-Yan reaction on nuclear targets.On the basis of Bjorken variable and scale dependence of the quark transport coefficient,the atomic mass dependence is incorporated.The quark transport coefficient is determined as a function of the atomic mass,Bjorken variable x and scale Q by the global fit of the experimental data.The determined constant factor of the quark transport coefficient is 0.062±0.006 Ge V~2/fm.The constant factor(?) in the quark transport coefficient is reduced by about 86.1%.It is found that the atomic mass dependence has a remarkable impact on the constant factor in the quark transport coefficient in cold nuclear matter.