Tracking saddle-to-scission dynamics using N/Z in projectile breakup reactions

Fragments produced in binary splits of an excited projectile-like fragment (PLF^*) formed in the reactions ¹²⁴Xe + ^112,124Sn at an incident energy of 50 MeV/A are examined. The dependence of the isotopic composition of light fragments (4⩽Z_L⩽8) on rotation angle allows one to explore changes in N/Z on the time scale of the rotational period of the PLF^*. Changes in the N/Z of the fragments persist for times as long as 2-3 zs (600-900 fm/c). The two-component nature of the time dependence of <N>/Z for Z_L=4 and the Z dependence are related to differences in the initial configurations and subsequent decay of the PLF^*.