The axial vector resonances, a1 and h1, in the π−p charge exchange reaction

A partial-wave analysis based on the isobar model has been carried out for a high statistics π + π − π 0 data in the π − p charge exchange reaction in the mass range between 0.88 and 1.44 GeV. Two axial-vector resonances, a 1 (1260) and h 1 (1170), were observed in the analysis. The masses and widths of a 1 and h 1 were determined by fitting the partial-wave amplitude to the Breit Wigner formula at four t' regions.