相对论重离子碰撞中粒子产生和/比率

Production and /Ratio in Relativistic Heavy Ion Collisions

利用强子输运 -弦碎裂模型研究了 2 0 0AGeV重离子碰撞中 Λ多重产生和 Λ / p比率 .研究了它们随反应系统大小和碰撞中心度的变化 .研究表明 Λ和 p多重数都随反应系统增大和随碰撞中心度提高而增大 ,但它们的比率基本保持不变 . Λ的湮没截面大小变化对 Λ的多重数产生有一定影响 ,但对 Λ / p比率影响不大 .结果很好地再现了 pp反应中 Λ/ p比率 .并获得这一比率在AA反应中是pp反应中的 3—

The multiplicity and ?/ ratio are studied by hadron transportation string fragmentation model in relativistic heavy ion collisions. Firstly, the dependence of multiplicity and ?/ ratio on the system size and the collision centrality is studied. It shows that the and multiplicities go up as the increase of system size and the increase of collision centrality. However, their ratio keeps almost a constant. The effect of annihilation cross section to multiplicity and ?/ ratio is also studied. It is found that this effect is weak: multiplicity and ?/ ratio have a little amount of increase by the decrease of annihilation cross section. Even the cross section is down to zero, ?/ ratio is only 1.2 in 200 A GeV AuAu head on collision. The ?/ ratio is obtained to be 0.28 in pp collision, lying in the range of experimental data:0.2—0.3. It is also obtained that the ratio in AA collisions is 3—5 times of that in pp collision.