标题： $J/ψ$强子和弦级联模型中的正常和反常抑制 显示英文标题

标题： $J/ψ$ normal and anomalous suppressions in a hadron and string cascade model

摘要： 引入了一种在弦的色电场中有效解离$c\bar{c}$对的新机制到强子和弦级联模型中，即基于LUND模型的JPCIAE模型，用于模拟超相对论核-核碰撞。 这种新机制与已知的核吸收机制（包括重子和介子）一起能够很好地再现正常和异常$J/\psi$抑制的数据，在动量偏移为200 A GeV/c时的最小偏差pA、AB（轻弹射体）以及Pb+Pb碰撞中。 然而，$J/\psi$抑制因子在动量偏移（\(E_T\)）依赖性方面，无论是S+U反应还是Pb+Pb反应，在200 A GeV/c和158 A GeV/c条件下均未得到很好的再现。 我们还测试了另一种机制，即领先粒子能量耗散机制，这使得在最小偏差pA、AB和Pb+Pb碰撞中的正常和异常$J/\psi$抑制以及$J/\psi$抑制因子的\(E_T\)依赖性都得到了更好的重现。 显示英文摘要

摘要： A mechanism for the effective dissociation of a $c\bar{c}$ pair in the colour electric field of strings is introduced into a hadron and string cascade model, i.e. JPCIAE, which is based on the LUND model, simulating ultra-relativistic nucleus - nucleus collisions. This new mechanism together with the known mechanism of nuclear absorption (both baryons and mesons) could reproduce fairly the data of the normal and anomalous $J/\psi$ suppressions in minimum bias pA, AB (with light projectile), and Pb + Pb collisions at 200 A GeV/c. However the impact parameter (E_T) dependence of the $J/\psi$ suppression factor, both, in S + U and Pb + Pb reactions at 200 A GeV/c and 158 A GeV/c, respectively, is not well reproduced. We also tested the additional mechanism of the energy degradation of leading particles, with which both, the normal and anomalous $J/\psi$ suppressions in minimum bias pA, AB, and Pb + Pb collisions and the E_T dependence of the $J/\psi$ suppression factor are better reproduced.