MEASUREMENTS OF BRANCHING RATIO AND FORM OF INTERACTION FOR BETA DECAY OF LAMBDA HYPERON

In a stopping-K- exposure of the Brookhaven National Laboratory 30-in. hydrogen bubble chamber, we have found 204 Λ β decays, Λ→p+e-+ν̄e, with a scanning efficiency of 0.97±0.02. We obtain a branching ratio of (0.80±0.08)×10-3. Using SU(3) and conservation of vector current to determine the weak-magnetism to vector form-factor ratio in the baryon current, we find an axial-vector-to-vector ratio of 0.72-0.14+0.19. The results are in good agreement with Cabibbo theory and are insensitive to the relative strength of weak magnetism. © 1969 The American Physical Society.