Isospin Dependence Of The Nuclear Equation Of State

核态方程的同位旋依赖性

• 批准号: 1066031
• 负责人: Jorge Lopez
• 金额: $ 18.6万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1066031&HistoricalAwards=false
• 关键词: Isospin; Dependence; Nuclear; Equation; State

This study will extract the isospin dependence of the Equation of State (EoS) of nuclear matter from several angles. Using classical molecular dynamics (CMD) we will study the dependence of nuclear binding energy on isospin in nuclei on their ground state, in infinite nuclear matter at a range of density, temperature and isospin conditions, in excited nuclei at varying densities,temperatures and isospin, and in reactions between nuclei with different isospin compositions. The classical molecular dynamics model to be used is based on proton-proton, neutron-neutron and proton-neutron potentials obtained by the Urbana/Champaign group, and it does not have any adjustable parameters and does not need the addition of fragment-producing codes or fluctuations extraneous to the reaction. The project will study the isoscaling dependence (relating nuclei with different neutron-proton ratios) of binding energies of ground-state nuclei (to obtain isospin extensions of the Weissacker mass formula with explicit functional dependence on isospin), the study of the isoscaling dependence of the EoS of infinite nuclear matter (to provide analytical expressions for the energy per particle with explicit dependences on density, temperature and isospin), the study of the isoscaling dependence of the EoS of excited nuclei (to obtain an effective nuclear EoS that could be used to extract experimental information from reactions), and it will investigate nuclear reactions to understand how to extract information about the EoS and its isospin dependence through studies of the neutron and proton flow during the reaction, isospin transport ratio, fractionation, double spectral ratios and isoscaling to assess the value of the isoscaling parameters as probes of the symmetry energy term of the EoS. All computations will be linked to experimental data from Michigan State University, Texas A&M University, and other accelerators.The intellectual merit of the proposed activity will be to learn about the unexplored role of isospin in nuclear forces, to refine a computational model - which can be used to test other codes, and to guide experimentalists in designing their experiments in the new facilty under construction in Michigan. The project will be carried out at the University of Texas at El Paso with the participation of undergraduate students and in collaboration with Prof. Claudio Dorso of the University of Buenos Aires. An effort will be made to incorporate Hispanic students (both male and female) into this project. The broader impact of the project is a benefit to nuclear physics, the recruitment of students to the growing physics area of rare isotopes, the support of nuclear physics as a research option at UTEP and in El Paso, the training of undergraduate students in research methodology, and the introduction of Hispanic students into physics research.

本研究将从多个角度提取核物质状态方程(EOS)的同位旋依赖性。我们将利用经典分子动力学(CMD)研究原子核中同位旋对基态的依赖关系，无限大核物质中不同密度、温度和同位旋条件下的核结合能，不同密度、温度和同位旋条件下激发核中的结合能，以及不同同位旋组成的原子核之间的反应。要使用的经典分子动力学模型是基于Urbana/Champaign群获得的质子-质子、中子-中子势和质子-中子势，它没有任何可调节的参数，也不需要添加碎片产生代码或反应以外的波动。该项目将研究基态核结合能的同位旋依赖关系(将具有不同中质子比的核联系起来)(以获得对同位旋具有显式泛函依赖的Weissacker质量公式的同位旋扩展)，研究无限核物质的状态方程的同位旋依赖关系(提供每个粒子的能量的解析表达式，明确地依赖于密度、温度和同位旋)，研究激发核的状态方程的同位旋依赖关系(以获得可用于从反应中提取实验信息的有效的核状态方程)，它将研究核反应，通过研究反应过程中的中子和质子流动、同位旋输运比、分馏、双谱比和等标度来评估等标度参数作为Eos对称能项探针的价值，以了解如何提取关于Eos及其同位旋依赖的信息。所有计算都将与来自密歇根州立大学、德克萨斯农工大学和其他加速器的实验数据相关联。拟议活动的智力价值将是了解同位旋在核力中尚未探索的作用，改进计算模型--该模型可用于测试其他代码，并指导实验者在密歇根正在建设的新设施中设计实验。该项目将在得克萨斯大学埃尔帕索分校进行，本科生参与，并与布宜诺斯艾利斯大学的克劳迪奥·多尔索教授合作。将努力将西班牙裔学生(包括男性和女性)纳入这一项目。该项目的更广泛影响是有利于核物理，招收学生到日益增长的稀有同位素物理领域，支持将核物理作为UTEP和埃尔帕索的一种研究选择，对本科生进行研究方法培训，并将拉美裔学生引入物理研究。