Study of the Six-Loop Beta Function of the $\lambda\phi^4_4$ Theory
  We investigate whether the six-loop beta function of the $\lambda \phi^4_4$ theory exhibits evidence for an ultraviolet zero. As part of our analysis, we calculate and analyze Pad\'e approximants to this beta function. Extending our earlier results at the five-loop level, we find that in the range of $\lambda$ where the perturbative calculation of the six-loop beta function is reliable, the theory does not exhibit robust evidence for an ultraviolet zero. 
Robert Shrock
hep-th