Results of a search for 2$\beta$-decay of $^{136}$Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory

TL;DR

This experiment searched for neutrinoless and two-neutrino double beta decay of $^{136}$Xe using high-pressure copper counters at Baksan, setting new lower limits on decay half-lives but finding no evidence of decay.

Contribution

First search for $^{136}$Xe double beta decay using high-pressure copper counters in Baksan, establishing new half-life limits without observing decay events.

Findings

No evidence of 2$eta$-decay detected.

Half-life limits: T$_{1/2}$$ geq$8.5×10^{21} yr (2$ u$) and 3.1×10^{23} yr (0$ u$).

Data collected over 8000 hours.

Abstract

The experiment for the 2$\beta$-decay of $^{136}$Xe search with two high-pressure copper proportional counters has been held in Baksan neutrino observatory. The search for the process is based on comparison of spectra measured with natural and enriched xenon. No evidence has been found for 2$\beta$(2$\nu$)- and 2$\beta$(0$\nu$)-decay. The decay half lifetime limit based on data measured during 8000 h is T$_{1/2}$$\geq8.5\cdot10^{21}$yr for 2$\nu$-mode and T$_{1/2}$$\geq3.1\cdot10^{23}$yr for 0$\nu$-mode (90%C.L.).