Single particle potential of a Sigma hyperon in nuclear matter

The isospin and spin dependence of the real part of the single-particle pot ential of a Sigma hyperon in nuclear matter, (V) over cap(Sigma), is invest igated. The isospin, spin, and spin-isospin dependent parts V-tau, V sigma, and V-sigma tau of (V) over tilde(Sigma) are expressed in terms of an effe ctive Sigma N interaction in nuclear matter. With suitable approximations n umerical results for V-tau,V-sigma, and V-sigma tau are obtained for four m odels of the Nijmegen baryon-baryon interaction. A comparison with recent ( K-, pi(+/-)) experiments favors model F as a realistic representation of th e Sigma N interaction.