Dipolar degrees of freedom and isospin equilibration processes in heavy ion collisions

The dipolar degrees of freedom on the 48Ca + 27Al system at 40 MeV/nucleon have been investigated for thefirst time with the 4π multidetector CHIMERA. The global variable Dz was measured for well-reconstructedevents in binary dissipative processes. Both the close link with isospin equilibration processes and its insensitivityto later statistical hot source decays have been discussed. This latter feature provides the opportunity to investigateglobally and exclusively the dynamics of the equilibration processes. At this first level of investigation theexperimental evidence, supported by the study of the reference system 27Al + 40Ca and the auxiliary one 27Ca + 48Ca, substantially agree with the CoMD-III calculations by describing the isovectorial forces through stiffnessparameter values γ ≈ 0.8–1.2.

The dipolar degrees of freedom on the Ca-48 + Al-27 system at 40 MeV/nucleon have been investigated for the first time with the 4 pi multidetector CHIMERA. The global variable < Dz > was measured for well-reconstructed events in binary dissipative processes. Both the close link with isospin equilibration processes and its insensitivity to later statistical hot source decays have been discussed. This latter feature provides the opportunity to investigate globally and exclusively the dynamics of the equilibration processes. At this first level of investigation the experimental evidence, supported by the study of the reference system Al-27 + Ca-40 and the auxiliary one Ca-27 + Ca-48, substantially agree with the CoMD- III calculations by describing the isovectorial forces through stiffness parameter values gamma approximate to 0.8-1.2.