Cosmic-string-loop fragmentation

We present the results of a numerical simulation of the fragmentation of single cosmic-string loops in flat spacetime. The analytic solution for the motion of the fragmenting loop is derived, and this solution is followed forward to determine the trajectories of the daughter loops. We find that loop fragmentation is not stochastic; the loop fragmentation probability decreases with fragmentation generation, and a universal loop fragmentation probability is not well defined. All of the loops sampled eventually reached nonintersecting trajectories. We see no evidence for fragmentation down to arbitrarily tiny loops. The final loop size distribution is approximately a lognormal distribution. The mean final loop velocity is v/similar to/0.6c