Waiting for the proton to decay: 1983 results from the new dedicated experiments

Abstract

Three new dedicated experiments searching for proton decay came on the air during the last year or so. Orders of magnitude more neutrino events, as well as possible nucleon decay candidates, have been recorded. Significant new limitss have been placed on many modes of nucleon decay. Representative lower limits at 90% C.L. for the lifetime/branching ratio for p→e+π0 of 2.0×1032 years, p→e+K0 of 3.1×1031 years, p→μ+K0 of 2.6×1031 years, and n→ν̄K0 of 0.8×1031 years have been set by the IMB group. Many other limits have also been set by the HPW, IMB, Kamioka, Kolar, and Mont Blanc experiments. Contained interactions have been observed in four detectors at rates expected from atmospheric neutrino induction, within the 30‐50% errors on the calculations. The status1 of the operational experiments is discussed, and typical restrictive results are reviewed. Detectors under construction are also mentioned.