Flavor decomposition of the pion-nucleon $\sigma$-term

Abstract

We re-analyze the flavor decomposition of the pion-nucleon $\sigma$-term in the framework of baryon chiral perturbation to fourth order. We employ a covariant and the heavy baryon framework including also the low-lying decuplet. Using only continuum data, we find a small strangeness content of the proton. The uncertainties are, however, large and might be overcome by dedicated lattice QCD calculations.

Comments: 31 pages, 1 figure, published version, some minor modifications