p-A碰撞中领头粒子Λ产生的靶依赖研究  

Target Dependence of Leading Production in p-A Collisions

作　　者：明庭尧[1] 冯笙琴[2] 谢炜[3] 

机构地区：[1]重庆大学城市科技学院,重庆402167 [2]三峡大学理学院,湖北宜昌443002 [3]桂林理工大学理学院,广西桂林541004

出　　处：《桂林理工大学学报》2011年第1期164-167,共4页Journal of Guilin University of Technology

基　　金：湖北省自然科学基金青年杰出人才项目(06ABB036);湖北省教育厅重大科研项目(03Z002)

摘　　要：利用循环迭代的混合事件方法分析19 GeV能量下质子轰击固定铍核的实验数据,给出领头奇异粒子Λ的dN/dy分布,发现在向前快度区域领头奇异粒子Λ被强烈的抑制,并与质子-铅的数据作比较,研究领头粒子Λ产生的靶依赖关系。结果发现:在中等快度区间,Λ产生的几率基本上相同;但随着快度增大,靶越重,产生奇异夸克的几率却越小。另外p-Be作用和p-Pb作用产生的p/n分布基本一致,这更进一步说明传统的双夸克-夸克碎裂机制已经不太可能是p-A碰撞中唯一合理的碎裂过程,还需要发展三夸克和胶子弦结碎裂机制。The comprehensive measurement of leading particle Λ production in p-Be collisions at 19 GeV is presented.Leading Λ′s production in the forward rapidity region compared with the non-strange leading baryons is strongly suppressed through the dN/dy distribution.The target dependence of leading production in p-A reaction is studied and compared with the analysis of p-Pb collisions.It is found that the more heavy target,the less probability of the strange quarks production with the increasing rapidity,but nearly the same at midrapidity.However,the p/n ratio in p-Be interactions is nearly the same with that in p-Pb interactions,indicating more strong simple diquark-quark fragmentation scheme and a proton to neutron ratio of two,unlikely to the only relevant process in p-A collisions for leading baryons in rapidity acceptance.To explain a p/n ratio of unity other fragmentation schemes are included,dominating the diquark-quark fragmentation in relevant kinematics region,such as three quark fragmentation and/or gluon junction fragmentation.

关 键 词：领头粒子 混合事件方法 dN/dy分布 靶依赖关系 

分 类 号：O571.42[理学—粒子物理与原子核物理]