N/Z equilibration

The N/Z, or ratio of neutron to proton, degree of freedom may be used to study intermediate energy nuclear collisions to give information about the origin of emitted collision fragments. Establishing under what conditions the onset of N/Z equilibrium occurs will give a better understanding of the physics of the equation of state through the use of simulation codes. If the nuclear equation of state can be elucidated in terms of the N/Z dependent component and how the N/Z dependent component varies with density, then the equilibrium ratio of protons to neutrons inside high density neutron stars can be inferred, allowing for prediction of cooling rates and supernovae mechanisms. In the current study, isotopic and isobaric ratios at thetalab=40o with cuts of 10% and 20% most central events, respectively, are studied for their N/Z equilibration signals. Light charged particles, or LCPs, are found to be emitted from systems which have not yet fully N/Z combined; the fragments with A=3 are emitted from the least equilibrated systems. Intermediate mass fragments, or IMFs, are seen to be emitted by N/Z equilibrated sources, within statistical error bars. The N/Z tracer method is used with ratios of isotopes and isobars to see how the amount of nuclear stopping or N/Z mixing changes as a function of the centrality of the event. The N/Z observable is used to reinvestigate earlier findings of the isotope and isobar ratio observables and shows the progression (or lack of it, in some cases) of the N/Z equilibration. This observable has proven to be a clear and sensitive tool to use when considering the differences in N/Z mixing of the systems at two energies.