Strength of the Sigma Single-Particle Potential in Nuclei From Semiclassical Distorted Wave Model Analysis of (π^-,K^+) Inclusive Spectrum

Semiclassical distorted wave model is developed to describe $(\pi^-,K^+)$ inclusive spectra related to $\Sigma^-$-formation measured at KEK with $p_\pi =1.2$ GeV/c. The shape and magnitude of the spectrum on $^{28}$Si target are satisfactorily reproduced by a repulsive $\Sigma$-nucleus potential, the strength of which is of the order of 30$\sim$50 MeV. This strength is not so strong as more than 100 MeV suggested by the estimation presented in the report of the experiment.