弹靶核的形变效应对中能区U+U碰撞的影响  

Effects of nuclear deformation in U+U collisions at the intermediate energy

作　　者：杨佳烨 刘玲[1] 李鹏程 王永佳[2] 李庆峰[2,1,3,4] YANG JiaYe;LIU Ling;LI PengCheng;WANG Yong Jia;LI QingFeng(College of Physics Science and Technology,Shenyang Normal University,Shenyang 110034,China;School of Science,Huzhou University,Huzhou 313000,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]沈阳师范大学物理科学与技术学院,沈阳110034 [2]湖州师范学院理学院,湖州313000 [3]兰州大学核科学与技术学院,兰州730000 [4]中国科学院近代物理研究所,兰州730000

出　　处：《中国科学：物理学、力学、天文学》2021年第11期83-91,共9页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:11875125,U2032145,12047568);国家重点研发计划(编号:2020YFE0202002);浙江省万人计划(编号:2018R52017)资助项目。

摘　　要：原子核的形变一直以来都是核结构研究中的重要内容之一,近年来,核结构效应对核反应或者重离子碰撞的影响受到越来越多的关注.本文基于极端相对论量子分子动力学(UrQMD)模型,在初始化部分考虑弹靶核的形变效应,模拟入射能量为0.4 GeV/nucleon下的^(238)U+^(238)U碰撞,探究了初始化时弹靶核的形变对于反应末态粒子集体流、π^(-)/π^(+)产额比以及核阻止本领等观测量的影响.研究发现,在形变原子核的尖对尖(长轴对长轴)碰撞中核阻止本领最大.腰对腰(短轴对短轴)的完全中心碰撞(b=0 fm)时,仍然有椭圆流产生.尖对尖碰撞给出的π^(-)/π^(+)产额比大于腰对腰碰撞给出的结果.此外,在本文所研究的体系和能量下,铀核的形变对质子椭圆流的影响大于对称能对它的影响,但中子质子椭圆流之比几乎不受初始铀核形变效应的影响.Nuclear deformation is an important topic in the study of nuclear structure. The influence of nuclear structure on nuclear reactions and heavy-ion collisions has attracted considerable attention recently. Based on the ultra-relativistic quantum molecular dynamics(Ur QMD) model, the effect of nuclear deformation in ^(238)U+^(238)U at the beam energy of0.4 Ge V/nucleon is investigated and several observables, such as the stopping power, collective flow, and π^(-)/π^(+)yield ratio, are calculated. It is found that the stopping power obtained with tip-tip(the two nuclei with their long axes head-on)collisions is the largest among collisions with different deformations. For belly-belly(the two nuclei with their short axes head-on and long axes parallel in the reaction plane) collisions, the elliptic flow exists even for the most central collision(b=0 fm). π^(-)/π^(+)yield ratio obtained with tip-tip collision is larger than that obtained with belly-belly collision. In addition,the influence of nuclear deformation on the elliptic flow of free protons is stronger than that of nuclear symmetry energy in ^(238)U+^(238)U collisions at 0.4 Ge V/nucleon, while the elliptic flow ratio between neutrons and protons shows hardly any sensitivity to different deformations of uranium.

关 键 词：重离子碰撞 集体流 原子核形变 对称能 

分 类 号：O571[理学—粒子物理与原子核物理]