p-A和A-A碰撞中重夸克偶素的产生和吸收机制

Charmonium Production and Absorption in P-A and A-A Collision

考虑了色单态和色八重态的贡献后，我们计算了固定靶情况下和的产生截面．并把结果用来研究p-A碰撞中压低和的产额比值问题．当-核子相互作用的截面对。取为，对取为0mb时，计算结果和实验数据符合得很好．推广此模型，考虑同行粒子对的吸收，并用它来讨论A-A碰撞的情况，计算结果表明，在相同的条件下，这个模型不能同时解释S-U和Pb-Pb碰撞的实验结果．最后讨论了S-U和Pb-Pb碰撞中QGP形成的可能性．

J / Ψ and Ψ′ production cross sections in fixed-target experiment is calculated, considering the contributions from both color-singlet and color- octet mechanisms. The resultS are applied to the investigations of the J /Ψ suppression and the Ψ′ / Ψ ratio problems in p-A collisions. The results agree with the experimental data as the -nucleon absorption cross sections and 0mb for .The model is further used to investigate A-A collisions when comover absorption mechanism is also considered. It is found that the observed experiment data of J /Ψ and Ψ′ / Ψ ratio in S-U collisions and Pb-Pb collisions can not be explained consistently within this model. The possibility of QGP formation in S-U and Pb-Pbcollisions is also discussed.