Leading logarithms for the nucleon mass

Within the heavy baryon chiral perturbation theory approach, we have studied the leading logarithm behavior of the nucleon mass up to four-loop order exactly and we present some results up to six-loop order as well as an all-order conjecture. The same methods allow to calculate the main logarithm multiplying the terms with fractional powers of the quark mass. We calculate thus the coefficients of m(2n+1) log((n-1)) (mu(2)/m(2)) and m(2n+2) log(n) (mu(2)/m(2)) with m the lowest-order pion mass. A side result is the leading divergence for a general heavy baryon loop integral. (C) 2014 The Authors. Published by Elsevier B.V.