π−πPhase Shifts in the Region 1.0-1.4 GeV/c2

Abstract

$\pi \pi$ scattering in the di-pion mass region 1.0-1.4 GeV is analyzed. It is shown that an anomaly of the ${\pi }^{-}{\pi }^{+}$ state in the region 1.0-1.2 GeV is either an $I=0\mathrm{}$ $D$-wave amplitude which interferes with a nearly static $I=1\mathrm{}$ $P$-wave amplitude or a Breit-Wigner $D$ wave which interferes with a moving $P$ wave (possibly resonant). The $f^0$ meson seems to show considerable inelasticity.