NON-GAUSSIAN CORRECTIONS TO HIGGS MASS IN AUTONOMOUS LAMBDA-PHI(3+1)(4)

Recent calculations in one-loop and Gaussian approximation, using the so-called autonomous renormalization scheme, indicate a comparatively massive, narrow Higgs excitation at about 2 TeV. Here I show that this result persists in the framework of a post-Gaussian variational appro ximation for the pure O(N)-symmetric phi4-theory for N > 1. The method is based on nonlinear transformations of path-integral variables, and the optimization amounts to a Schwinger-Dyson-type summation of diagr ams. In the case of O(4), for example, I find M(Higgs) = 2.3 TeV, comp ared with 1.9 TeV and 2.1 TeV in one-loop and Gaussian approximation, respectively. My results are also consistent with the Consoli-Stevenso n conjecture that the Gaussian and one-loop results for N = 1 are exac t and may even hold for general N.