Quark-mass dependence of baryons in QCD with 2+1 flavors

Over the past few years the quark-mass dependence of baryon properties has been studied in detail via Lattice QCD simulations with 2 light quark flavors. For example, the observed quark-mass dependence of the mass of a nucleon is now well understood within the context of baryon chiral perturbation theory (ChPT), which can also correct for extra mass-shifts arising from the finite simulation volume. Currently simulations with 2+1 quark-flavors are one of the frontier research areas in Lattice QCD studies of baryon structure. However, all attempts to understand the observed quark-mass dependencies within the context of ChPT have failed so far, as the addition of a third flavor brings in several complications for the effective field theory of low energy QCD. In this talk we present new results on the quark-mass dependencies of the masses of octet baryons. We also explain how we systematically overcome the previous problems of chiral extrapolation studies for baryon observables in the case of 2+1 quark flavors.