Chemical potential and symmetry energy for intermediate-mass fragment production in heavy ion reactions near the Fermi energy.

Ratios of differential chemical potential values relative to the temperature, (µn - µp)/T, extracted from isotope yields of 13 reaction systems at 40 MeV/nucleon are compared to those of a quantum statistical model to determine the temperature and symmetry energy values of the fragmenting system. The experimental (µn - µp)/T values are extracted based on the modified Fisher model. Using the density value of ρ/ρ0 = 0.56 from the previous analysis, the temperature and symmetry energy values of T = 4.6 ± 0.4 MeV and asym = 23.6 ± 2.1 MeV are extracted in a framework of a quantum statistical model. These values agree well with those of the previous work, in which a self-consistent method was utilized with antisymmetrized molecular dynamics simulations. The extracted temperature and symmetry energies are discussed together with other experimental values published in literature. [ABSTRACT FROM AUTHOR]