Remarks on the pion-nucleon sigma-term
  The pion-nucleon $\sigma$-term can be stringently constrained by the combination of analyticity, unitarity, and crossing symmetry with phenomenological information on the pion-nucleon scattering lengths. Recently, lattice calculations at the physical point have been reported that find lower values by about $3\sigma$ with respect to the phenomenological determination. We point out that a lattice measurement of the pion-nucleon scattering lengths could help resolve the situation by testing the values extracted from spectroscopy measurements in pionic atoms. 
Martin Hoferichter, Jacobo Ruiz de Elvira, Bastian Kubis, Ulf-G.   Mei{\ss}ner
hep-lat hep-ph nucl-th