Equilibration and equilibration rates have been measured by colliding Sn nuclei with different isospin asymmetries at beam energies of E/A = 35 MeV. Using the yields of mirror nuclei of (7)Li and (7)Be, we have studied the diffusion of isospin asymmetry by combining data from asymmetric (112)Sn + (124)Sn and (124)Sn + (112)Sn collisions with those from symmetric (112)Sn + (112)Sn and (124)Sn + (124)Sn collisions. We use these measurements to probe isospin equilibration in central collisions where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion principle. The results are consistent with transport theoretical calculations that predict a degree of transparency in these collisions, but inconsistent with the emission of intermediate mass fragments by a single chemically equilibrated source. Comparisons with quantum molecular dynamics calculations are consistent with results obtained at higher incident energies that provide constraints on the density dependence of the symmetry energy.

Isospin diffusion and equilibration for Sn + Sn collisions at E/A = 35 MeV

GERACI, Elena Irene;POLITI, Giuseppe;RIZZO, Francesca;
2010

Abstract

Equilibration and equilibration rates have been measured by colliding Sn nuclei with different isospin asymmetries at beam energies of E/A = 35 MeV. Using the yields of mirror nuclei of (7)Li and (7)Be, we have studied the diffusion of isospin asymmetry by combining data from asymmetric (112)Sn + (124)Sn and (124)Sn + (112)Sn collisions with those from symmetric (112)Sn + (112)Sn and (124)Sn + (124)Sn collisions. We use these measurements to probe isospin equilibration in central collisions where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion principle. The results are consistent with transport theoretical calculations that predict a degree of transparency in these collisions, but inconsistent with the emission of intermediate mass fragments by a single chemically equilibrated source. Comparisons with quantum molecular dynamics calculations are consistent with results obtained at higher incident energies that provide constraints on the density dependence of the symmetry energy.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/54047
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