Equilibration chronometry: characterizing neutron-proton equilibration within a strongly deformed nuclear system with sub-zeptosecond resolution

Neutron-proton equilibration was studied in dynamically-deformed nuclei produced in reactions 70 Zn+ 70 Zn at 35A MeV.The composition of the two largest daughters of each excited projectilelike fragment is examined as a function of alignment angle.The lighter fragment is initially neutron rich relative to the heavier fragment, and the compositions evolve towards each other exponentially with increasing angle.The alignment angle, as a result of rotation, is related to time through the angular momentum of the projectile-like fragment, and a rate constant of 3 zs -1 is extracted.This corresponds to a mean equilibration time of 0.3 zs.This technique provides a new window through which to gain insight into the nuclear equation of state.