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.
