  We report the results of extensive Dynamic Monte Carlo simulations of systems
of self-assembled Equilibrium Polymers without rings in good solvent.
Confirming recent theoretical predictions, the mean-chain length is found to
scale as $\Lav = \Lstar (\phi/\phistar)^\alpha \propto \phi^\alpha \exp(\delta
E)$ with exponents $\alpha_d=\delta_d=1/(1+\gamma) \approx 0.46$ and $\alpha_s
= [1+(\gamma-1)/(\nu d -1)]/2 \approx 0.60, \delta_s=1/2$ in the dilute and
semi-dilute limits respectively. The average size of the micelles, as measured
by the end-to-end distance and the radius of gyration, follows a very similar
crossover scaling to that of conventional quenched polymer chains. In the
semi-dilute regime, the chain size distribution is found to be exponential,
crossing over to a Schultz-Zimm type distribution in the dilute limit. The very
large size of our simulations (which involve mean chain lengths up to 5000,
even at high polymer densities) allows also an accurate determination of the
self-avoiding walk susceptibility exponent $\gamma = 1.165 \pm 0.01$.
