Chiral extrapolation of the sigma resonance

Abstract

We analyze results on isoscalar ππ scattering from a Nf=2+1 lattice QCD calculation by the HadronSpectrum collaboration by re-summing the two-flavor chiral scattering amplitude of the next-to-leading order in the so-called inverse amplitude method. The lattice data can be well extrapolated to the physical pion mass. We also find that both I=0 and I=1 lattice data can be described simultaneously for pion masses up to Mπ=236 MeV. Our analysis of the lattice data suggests that the f0(500) or σ resonance becomes a bound state at Mπ≈320 MeV. A future lattice simulation at this pion mass can, therefore, be of large value for insight into properties of the isoscalar resonance. Keywords: Pion–pion scattering, S-matrix, resonances, Chiral extrapolations, Lattice QCD