We have analyzed low-energy pion-nucleon data for isospin invariance by comparing chargeexchange amplitudes derived from charge-exchange data with those predicted from recent~p elastic data through the application of isospin invariance. A discrepancy of the order of 7% is observed beyond the contributions of the~p Coulomb interaction and the hadronic mass differences. PACS numbers: 13.75.Gx, 24.80.Dc, 25.80.Gn fcEx = Of the eight reactions of the form~N~' N' the only three directly accessible experimentally are those with charged pion beams and proton targets: 7Tp elasticscattering, with amplitudes f, and 7r p~~" n chargeexchange (CEX) scattering, with amplitude fcEx. Isospin conservation gives a relationship among these three amplitudes, the triangle identity

No abstract

No abstract

No abstract