Nucleon mass, sigma term, and lattice QCD
Citations Over TimeTop 1% of 2004 papers
Abstract
We investigate the quark mass dependence of the nucleon mass ${M}_{N}.$ 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 ${p}^{4}.$ 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 $a<0.15\mathrm{fm}$ and ${m}_{\ensuremath{\pi}}L>5.$ We have also restricted ourselves to data with ${m}_{\ensuremath{\pi}}<600\mathrm{MeV}$ and ${m}_{\mathrm{sea}}{=m}_{\mathrm{val}}.$ A good interpolation function is found already at the one-loop level and chiral order ${p}^{3}.$ We show that the next-to-leading one-loop corrections are small. From the ${p}^{4}$ numerical analysis we deduce the nucleon mass in the chiral limit ${M}_{0}\ensuremath{\approx}0.88\mathrm{GeV}$ and the pion-nucleon sigma term ${\ensuremath{\sigma}}_{N}=(49\ifmmode\pm\else\textpm\fi{}3)\mathrm{MeV}$ at the physical value of the pion mass.