HYPERNUCLEAR AND LAMBDA-SPIN POLARIZATIONS PRODUCED IN THE (PI+, K+) REACTION

Starting with the elementary amplitudes having spin-flip and spin-nonf lip interactions for pi+n --> LAMBDAK+, hypernuclear production cross sections and polarizations have been estimated in detail for the (pi+, K+) reaction on available p-shell nuclear targets (B-10, B-11, C-12, C-13, N-14,O-16). The experimental excitation spectra of C-12(LAMBDA), C-13(LAMBDA), and O-16(LAMBDA), including the typical cross section d ata, are satisfactorily reproduced in the distorted wave impulse appro ximation with the configuration-mixed wave functions. The angular depe ndence of hypernuclear polarization is predicted for each typical stat e, showing, for example, that the use of the mixed wave functions chan ges appreciably the previous estimate with the simple one-particle-one -hole wave function for C-12(LAMBDA). The LAMBDA-spin polarization in nuclear medium is also estimated. Typical states are shown to have lar ge polarizations at the hypernuclear production stage.