Recent Progress in Double Beta Decay

Abstract

At least one neutrino has a mass of about 50 meV or larger. However, the absolute mass scale for the neutrino remains unknown. Studies of double beta decay offer hope for determining the absolute mass scale. Furthermore, the critical question: Is the neutrino its own antiparticle? is unanswered. In particular, zero-neutrino double beta decay (0νββ) can address the issues of lepton number conservation, the particle-antiparticle nature of the neutrino, and its mass. A summary of the recent progress in 0νββ, and the related technologies will be discussed in the context of the future 0νββ program.

Search for 2βdecay of116Cd with the help of enriched116CdWO4crystal scintillators

“…The observation of the 0ν2β decay will testify the lepton number non-conservation, the Majorana nature of the neutrino, an absolute value and hierarchy of the neutrino masses. The 0ν2β decay is also sensitive to an existence of the right-handed currents, hypothetical particles (majorons) and other effects beyond the SM (see the recent reviews [4][5][6][7][8][9] and references therein).…”

Rejection of randomly coinciding 2ν2β events in ZnMoO4scintillating bolometers

“…The approach is based on the calculation of the χ 2 parameter defined as (3) where the sum is over time channels k, starting from the origin of pulse and up to a certain time t n . The number of channels to calculate the have been optimized to reach a maximal rejection efficiency.…”

“…Observation of neutrinoless double beta (0ν2β) decay would imply the violation of lepton number conservation and definitely new physics beyond the Standard Model, establishing the Majorana nature of neutrino [1,2,3,4,5]. Cryogenic scintillating bolometers look the most promising detectors to search for this extremely rare process in a few theoretically favourable nuclei [6,7,8,9,10,11,12].…”

First results of the experiment to search for 2β decay of106Cd with106CdWO4crystal scintillator in coincidence with four crystals HPGe detector

“…01004-p. 3 To estimate limS values for the double beta processes in 106 Cd, the measured number of events in the background spectrum was compared with the expected background, which was estimated by using the result of the fit of the data accumulated by the 106 CdWO 4 detector without coincidence (see Fig. 3).…”

“…Experiments to search for double beta (2) decay are considered as a promising way to investigate properties of neutrino and search for effects beyond the Standard Model of particles [1,2,3,4,5]. The isotope 106 Cd (energy of decay Q 2 = 2775.39(10) keV [6], isotopic abundance  = 1.25(6)% [7]) is one of the most suitable nuclei to search for 2 processes with decrease of nuclear charge (see e.g.…”