A search for double beta decays of tin isotopes with enhanced sensitivity

TL;DR

This study searches for double beta decay modes in tin isotopes 124Sn and 112Sn, setting new half-life limits and exploring decay channels with enhanced sensitivity using 75 kg.days of data.

Contribution

It provides the first experimental limits on various double beta decay modes of tin isotopes with improved sensitivity and explores potential resonant enhancements in decay rates.

Findings

New half-life limits for excited states in 124Sn

Limits on double electron capture in 112Sn

No observation of de-excitation gammas from 0+ state

Abstract

A search for the various double beta decay modes of 124Sn and 112Sn has been performed on 75 kg.days of data. New half-life limits for excited states in 124Sn have been obtained including a lower limit for the decay into the first excited 2+ state of 124Te of T_half > 0.87e20 yrs (90% CL) and into the first excited 0+ state of T_half > 1.08e20 yrs (90% CL). Ground state and excited state transitions of 112Sn have also been experimentally explored. A limit for the 2 neutrino double electron capture of T_half > 1.8e19 yrs (90% CL) is obtained. The non-observation of de-excitation gammas from the 0+ at 1888.5keV results in a lower half-life limit on the 0 neutrino double electron capture decay of 112Sn of T_half > 0.8e19 yrs (90% CL), despite a possible resonant enhancement of the decay rate due to degenerated states.