Numerical evaluation of a two loop diagram in the cutoff regularization

Abstract

The sunset diagram of $\lambda {\varphi }^4$ theory is evaluated numerically in cutoff scheme and a nonzero finite term (in accordance with dimensional regularization (DR) result) is found in contrast to published calculations. This finding dramatically reduces the critical couplings for symmetry breaking in the two loop effective potential discussed in our previous work.

Comments: 6 pages, revtex, to appear in Comm. Theor. Phys