Results of an investigation of the O(4) spin model at finite temperature using anisotropic lattices are presented. In both the large N approximation and numerical simulations using the Wolff cluster algorithm we find that the ratio of the symmetry restoration temperature T(SR) to the Higgs mass m(H) is independent of the anisotropy xi. From the numerical simulations we obtain a lower bound of T(SR)/m(H) congruent-to 0.58 +/- 0.02 at a value for the Higgs mass m(H)a(s) congruent-to 0.5, which is lowered further by about 10% at m(H)a(s) congruent-to 1. Requiring certain timelike correlation functions to coincide with their spacelike counterparts, quantum and scaling corrections to the anisotropy are determined and are found to be small i.e., the anisotropy is found to be close to the ratio of spacelike and timelike lattice spacings.
The document is publicly available on the WWW