Equilibration of N/Z in binary breakup of an excited and transiently deformed projectile-like fragment (PLF*), produced in peripheral collisions of 64Zn + 27Al, 64Zn, 209Bi at E/A = 45 MeV, is examined. The composition of emitted light fragments (3=Z=6) changes with the decay angle of the PLF*. The most neutron-rich fragments observed are associated with a small rotation angle. A clear target dependence is observed with the largest initial N/Z correlated with the heavy, neutron-rich target. Using the rotation angle as a clock, we deduce that N/Z equilibration persists for times as long as 3-4 zs (1zs = 1 x 10-21s = 300 fm/c). The rate of N/Z equilibration is found to depend on the initial neutron gradient within the PLF*. This work was supported by the U.S. Department of Energy under Grant Nos. DEFG02-88ER-40404 (IU) and DE-FG03-93ER40773 (TAMU). Support from the Robert A. Welch Foundation through Grant No. A-1266 is gratefully acknowledged. Collaboration members from Universit� Laval recognize the support of the Natural Sciences and Engineering Research Council of Canada.

Timescale for equilibration of N/Z gradients in dinuclear systems

246th National Meeting (2013)

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