Weak Radiative Decay Lambda-]N-Gamma And The Radiative-Capture Reaction K-P-]Sigma(1385)Gamma

The branching ratio for the A weak radiative decay LAMBDA --> ngamma has been measured. Three statistically independent results from the same experiment (Brookhaven E811) are reported here. They are combined with a previously published measurement, also from Brookhaven E811, to yield a result of (LAMBDA --> ngamma)/(LAMBDA --> anything) = (1.75+/-0.15) X 10(-3), based on 1800 events after background subtraction. This represents a factor of 75 increase in statistics over the previous world total. A comparison with recent theoretical papers shows that no existing model provides a completely satisfactory description of all data on weak radiative decays. A search is also reported for the radiative capture process K-p --> SIGMA(1385)gamma at rest. No signal was observed and an upper limit on the branching ratio of [K-p --> SIGMA(1385)gamma]/[K-p --> anything] < 4 X 10(-4) (90% C.L.) was determined.