| One of important purposes of high-energy heavy ion physics is to study strongly interacting dynamics in high energy density and high temperature environment. Quantum chromodaynamics predicts that at high temperature and high density a deconfined phase from hadronic matter to quark-gluon plasma will occur. There are many ways to diagnose signal for quark-gluon plasma, such as direct photon, dilepton enhancement, strangeness enhancement, J/ suppression and so on. The huge energy-momentum of particles can be transformed into thermal energy by accelerator experiment at high energy to study perturbative vacuum of quantum chromodynamics and determine the signal of quark-gluon plasma. Therefore in terms of relativistic heavy ion collisions it is possible for quark and gluon to deconfine in wider range and form quark-gluon plasma.The initial consideration of J/ ?suppression in deconfined medium is based on color screening. The radius of color screening in medium is in inverse proportion to the density of color charge and energy. When the radius of color screening is smaller than that of resonance state, strong interaction will decrease sharply and bound states can't exist. The appearance of J/ suppression inspires and attracts great attention. The invariant mass spectrum of dimuons can be used to examine the suppression of J/ production .J/ W consists of quark and anti-quark. Its size is small enough that perturbative theory is meaningful and is not small enough that non-perturbative effect can be completely ignored. Therefore J/ v is the border guard of perturbative quark and gluon and non-perturbative hadron. J/ v production can be divided into two phases:cc pairs are produced from initial short-range parton scattering in nucleus-nucleuscollision, then the produced cc pairs proceed to evolving into physical bound state.The former is within perturbative quantum chromodynamics domain and the latter is within non-perturbative quantum chromodynamics domain. Besides the formation of quark-gluon plasma, there are many mechanisms in hadron environment which lead to J/ suppression. Therefore it is necessary to study the contribution of hadron environment to the suppression. Many works have studied J/ suppression in hadron environment with Glauber model. But the combination of nucleus absorption and comover mechanism in hadron environment can not explain the abnormal suppression of J/ production in Pb-Pb collision yet.As we know, the experimentally observed result is the prompt J/ production,which include the direct J/ production, the decay of and the radiative feedown of Xcj. Once the direct charmonium production is known, the prompt J/production can be calculated. In high energy nucleus-nucleus collisons, cc pairs are produced through short-distance scattering process among partons. After thepoint-like cc pairs form, they can be dissociated by partonic and final hadronic matter. Not only mesons but also baryons in final haronic matter contribute to the dissociation of cc .We use the constituent exchange model at quark level incorporating quark confinement to calculate the Xa dissociation cross sections induced by baryons inhadronic matter with the Buchmtlller-Tye potential which embodies asymptotic free character of quantum chromodynamics. The interacting potential among quarks includes the contributions of coulomb-like, confinement and loop-originating correction. The wave functions describing meson and baryon are composed of orbital, color, spin and flavor. The transition matrix elements are obtained byanalytical method and the cross section is given by Monte-Carlo simulation. Then the dependences of the cross section on the center-of-mass energy of Xcj andbaryon are given in the work. The relative momentum of two final particles and the cross section are zero at the threshold energy for an endothermic reaction, while the relative momentum of two initial particles is zero and the cross section at the threshold energy for an exothermic reaction is infinite. The cross section...
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