Forward–backward emission of target evaporated fragments in high energy nucleus–nucleus collisions  

作　　者：张智 马田丽 张东海 

机构地区：[1]Institute of Modern Physics, Shanxi Normal University

出　　处：《Chinese Physics C》2015年第10期29-34,共6页中国物理C（英文版）

基　　金：Supported by National Science Foundation of China(11075100);Natural Science Foundation of Shanxi Province(2011011001-2);the Shanxi Provincial Foundation for Returned Overseas Chinese Scholars,(2011-058)

摘　　要：The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV ^4He, 3.7 A GeV ^16O, 60 A GeV ^16O, 1.7 A GeV ^84Kr and 10.7 A GeV ^197Au -induced emulsion heavy target （AgBr） interactions are investigated. It is found that the multiplicity distribution of target evaporated fragments emitted in both forward and backward hemispheres can be fitted by a Gaussian distribution. The multiplicity moments of target evaporated particles emitted in the forward and backward hemispheres increase with the order of the moment q, and the secondorder multiplicity moment is energy independent over the entire energy range for all the interactions in the forward and backward hemisphere. The scaled variance, a direct measure of multiplicity fluctuations, is close to one for all the interactions, which indicate a correlation among the produced particles. The entropy of target evaporated fragments emitted in both forward and backward hemispheres are the same within experimental errors.The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV ^4He, 3.7 A GeV ^16O, 60 A GeV ^16O, 1.7 A GeV ^84Kr and 10.7 A GeV ^197Au -induced emulsion heavy target （AgBr） interactions are investigated. It is found that the multiplicity distribution of target evaporated fragments emitted in both forward and backward hemispheres can be fitted by a Gaussian distribution. The multiplicity moments of target evaporated particles emitted in the forward and backward hemispheres increase with the order of the moment q, and the secondorder multiplicity moment is energy independent over the entire energy range for all the interactions in the forward and backward hemisphere. The scaled variance, a direct measure of multiplicity fluctuations, is close to one for all the interactions, which indicate a correlation among the produced particles. The entropy of target evaporated fragments emitted in both forward and backward hemispheres are the same within experimental errors.

关 键 词：relativistic heavy-ion collisions target fragmentation MULTIPLICITY nuclear emulsion 

分 类 号：O571[理学—粒子物理与原子核物理]