Problems in hypernuclear physics

The connection between the barion-barion interaction and the properties of hypernuclei, in particular Σ hypernuclei, is discussed. The inadequate accuracy of the so called low order Brueckner approximation is pointed out. The single particle Σ potential fitted to the pion spectrum measured in the (K-, π+) reactions appears to be repulsive. This eliminates some of the existing models of the barion-barion interaction.