FIRST OBSERVATION OF THE P(LAMBDA)-]S(LAMBDA) GAMMA-RAY TRANSITION INC-13(LAMBDA)

The spectrum of excited states in the hypernucleus C-13(Lambda) was st udied at the Brookhaven Alternate Gradient Synchrotron using the (K-, pi(-)) reaction on an enriched C-13 target. gamma rays coincident with the p(1/2 Lambda) state were observed using two large sodium iodide d etectors. We interpret them as arising from the p(1/2 Lambda) --> s(1/ 2 Lambda) transition in C-13(Lambda). This represents the first direct observation of a gamma ray associated with the transition of a hypero n between major nuclear shells.