轻粒子发射时间随测量角的变化  

Emission Time of Light Particles with Respect to Measurement Angle

作　　者：柳永英[1] 王素芳[1] 段利敏[1] 靳根明[1] 朱海东[1] 张保国[1] 文万信[1] 李祖玉[1] 贺智勇[1] 王宏伟[1] 肖志刚[1] 吴和宇[1] 魏志勇[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《高能物理与核物理》2001年第11期1065-1070,共6页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金 (1 9775 0 5 4 );中国科学院九五重大项目 (KJ95T -0 3 );中国科学院九五基础性研究重点科学基金资助~~

摘　　要：利用小相对角关联方法测量了 2 5MeV u40 Ar+ 93Nb反应中关联出射的轻粒子 .通过与三体弹道模型的比较 ,从关联函数提取了轻粒子的发射时间 .结果表明 ,轻粒子的发射时间随粒子能量的升高而降低 ,从低能的约 60 0fm c下降至高能的约 50fm c .将此数据与40 Ar+ 1 97Au反应中的发射时间进行了比较 ,发现随着实验室系角度的增加 ,提取的轻粒子的发射时间变长 ,并认为其原因在于随发射角度的增加 ,前平衡发射成份越来越少 。Particle particle correlation functions at small correlation angle have been measured for 40Ar+ 93Nb collision at E 25MeV/u. Based on three body trajectory calculation the emission time scale of light particles has been extracted from correlation function of two particles at small relative momentum. The mean emission time scale decreases with increasing sum of the kinetic energies of the particles in a correlated pair. It decreases from about 500 fm/c for low energy particles to about 50 fm/c for high energy particles. And the extracted emission time scales from larger detection angle are longer than that extracted from the data obtained at small detection angle, which can be explained as the more particles emitted from equilibrated system.

关 键 词：关联函数 三体弱道 发射时间 实验室系角度 测量角度 轻粒子 中能重离子碰撞 

分 类 号：O571[理学—粒子物理与原子核物理]