Results of a search for 2β decay of 136Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory

Abstract

A search for 2β decay of 136Xe with two high-pressure copper proportional counters was carried out in the Baksan Neutrino Observatory. The experiment is based on comparison of spectra measured with natural and enriched xenon. No evidence was found for 2β(2ν) and 2β(0ν) decay. The decay half-life limit based on data measured for 8000 h is T 1/2 ≥ 8.5 × 1021 yr for 2ν mode and T 1/2 ≥ 3.1 × 1023 yr for 0ν mode (90% C.L.).