Estimate of the sigma term in K+-p scattering

The σ term in K-p scattering is calculated using on-mass-shell dispersion relations, available data on the K±p total cross sections, and real parts of the forward scattering amplitude. The subthreshold contribution is minimized by introducing a factor which vanishes at the $Y_{0,1}^{*}$ peaks; this also yields information on the $Y_{0,1}^{*}pK$ coupling constants. Our result ${\sigma }^{Kp}~160$ MeV is rather insensitive to the choice of the ΛpK and ΣpK coupling constants. Within the (3, 3*) + (3*, 3) model our value for ${\sigma }^{Kp}$ favors small values of ${\sigma }^{\pi p}$.