Further Analysis on σ-particle Properties

Shin Ishida, Taku Ishida, Muneyuki Ishida, Kunio Takamatsu, Tsuneaki Tsuru

Published 1996-10-15, updated 1997-05-27Version 2

In a previous work, we have reanalyzed the I=0 S-wave \pi\pi-scattering phase-shift through a new method of Interfering Breit-Wigner amplitudes, and have shown the existence of a light scalar, \sigma particle, accompanied by a negative "repulsive core"-type background phase-shift, whose origin may have some correspondence to a ``compensating'' \pi\pi contact interaction. In this work we make further analysis on the phase shift under KKbar threshold from the same standpoint, to determine precise values of \sigma mass and width, so far as present experimental data are concerned.