Nucleon mass, sigma term and lattice QCD

Abstract

We present a study on the quark mass dependence of the nucleon mass and an extrapolation of this observable to two-flavor lattice QCD results in the framework of relativistic baryon chiral perturbation theory up to NNLO. Already at NLO we obtain a good chiral extrapolation function and we demonstrate that the NNLO corrections are reasonably small. From the NNLO extrapolation we find M_N= 910 +/- 70 MeV at the physical value of the pion mass. Furthermore, utilizing the same parameters determined in our numerical analysis of M_N we also examine the quark mass dependence of the pion-nucleon sigma term sigma_N, resulting in sigma_N= 53 +/- 8 MeV at the physical value of the pion mass.