Strangeness modes in nuclei tested by antineutrinos - art. no. 034610

The production of negative strangeness in reactions of inelastic antineutri no scattering on a nucleus provides information on the modification of stra nge degrees of freedom in nuclear matter. We calculate cross sections of th e reaction channels <(nu)over bar>(e(mu)) --> e(+) (mu(+)) + K- and <(nu)ov er bar>(e(mu)) + p --> Lambda + e(+) (mu(+)) and investigate their sensitiv ity to the medium effects. In particular, we consider effects induced by th e presence of a low-energy excitation mode in the K-spectrum, associated wi th correlated Lambda-particle and proton-hole states, and by renormalizatio n of the weak interaction in medium. In order to avoid double counting, var ious contributions to antineutrino scattering are classified with the help of the optical theorem, formulated within the nonequilibrium Green's functi on technique. [S0556-2813(99)01007-9].