Nucleon mass, sigma term, and lattice QCD

We investigate the quark mass dependence of the nucleon mass [Formula Presented] An interpolation of this observable, between a selected set of fully dynamical two-flavor lattice QCD data and its physical value, is studied using relativistic baryon chiral perturbation theory up to order [Formula Presented] In order to minimize uncertainties due to lattice discretization and finite volume effects our numerical analysis takes into account only simulations performed with lattice spacings [Formula Presented] and [Formula Presented] We have also restricted ourselves to data with [Formula Presented] and [Formula Presented] A good interpolation function is found already at the one-loop level and chiral order [Formula Presented] We show that the next-to-leading one-loop corrections are small. From the [Formula Presented] numerical analysis we deduce the nucleon mass in the chiral limit [Formula Presented] and the pion-nucleon sigma term [Formula Presented] at the physical value of the pion mass.