COMPUTING THE STRONG SPHALERON RATE

We measure the diffusion constant for Chern-Simons number for classica l, lattice SU(3) Yang-Mills theory, using a generalization of the topo logical definition of Chern-Simons number developed recently by Moore and Turok. The diffusion constant is much larger than that for SU(2), even before the ratio of coupling constants has been accounted for, wh ich implies that chiral quark number is efficiently destroyed by stron g processes during the electroweak phase transition. For the physical value of alpha(S) we estimate the decay time for chiral quark number t o be about 80/T, although various systematics make this number uncerta in by about a factor of 2. (C) 1997 Published by Elsevier Science B.V.