Evaluation of the Pion-Nucleon Sigma Term from CHAOS Data

Abstract

We have reanalyzed the ${\pi }^{\pm }p$ scattering data at low energy in the Coulomb-nuclear interference region as measured by the CHAOS group at TRIUMF with the aim to determine the pion-nucleon $\sigma$ term. The resulting value $\sigma =(44\pm 12)$ MeV, while in agreement with lattice QCD calculations and compatible with other recent analyses, is significantly lower than that from the GWU-TRIUMF analysis of 2002.