Nucleon-nucleon cross sections in neutron-rich matter and isospin transport in heavy-ion reactions at intermediate energies

Journal Article · Thu Dec 15 04:00:00 EST 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.72.064611· OSTI ID:20771120

Baoan, Li ^[1]; Liewen, Chen ^[2]

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1. Department of Chemistry and Physics, P.O. Box 419, Arkansas State University, State University, Arkansas 72467-0419 (United States)
2. Institute of Theoretical Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)

Nucleon-nucleon (NN) cross sections are evaluated in neutron-rich matter using a scaling model according to density, momentum, and isospin dependent nucleon effective masses. It is found that the in-medium NN cross sections are not only reduced but also have a different isospin dependence compared with the free-space ones. Because of the neutron-proton effective mass splitting the difference between nn and pp scattering cross sections increases with the increasing isospin asymmetry of the medium. Within the transport model IBUU04, the in-medium NN cross sections are found to influence significantly the isospin transport in heavy-ion reactions. With the in-medium NN cross sections, a symmetry energy of E{sub sym}({rho}){approx_equal}31.6({rho}/{rho}{sub 0}){sup 0.69} was found most acceptable compared with both the MSU isospin diffusion data and the presently acceptable neutron-skin thickness in {sup 208}Pb. The isospin dependent part K{sub asy}({rho}{sub 0}) of isobaric nuclear incompressibility was further narrowed down to -500{+-}50 MeV. The possibility of determining simultaneously the in-medium NN cross sections and the symmetry energy was also studied. The proton transverse flow, or even better the combined transverse flow of neutrons and protons, can be used as a probe of the in-medium NN cross sections without much hindrance from the uncertainties of the symmetry energy.

• OSTI ID: 20771120
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 6 Vol. 72; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ASYMMETRY
CROSS SECTIONS
EFFECTIVE MASS
HEAVY ION REACTIONS
ISOSPIN
LEAD 208
MEV RANGE
NEUTRON-NEUTRON INTERACTIONS
NEUTRONS
NUCLEAR FORCES
NUCLEAR MATTER
PROTON-PROTON INTERACTIONS
PROTONS
SCATTERING
SYMMETRY
TRANSPORT THEORY