Double beta decay

Neutrinoless double-beta decay and other rare decays studied using massive calorimeters. 

In a cryogenic experiment, one or several detectors are used for a definite goal for which they have been optimized. For example, in CUORE experiment described in Section 16.5, the sensors are the Ge thermistors, i.e. thermometers used in a small temperature range (around 10 mK). One detector is a bolometer made up of an absorber and a Ge sensor. The experiment is the array of 1000 bolometers arranged in anticoincidence circuits for the detection of the neutrinoless double-beta decay. Note that the sensors, if calibrated, could be used, as well, as very low-temperature thermometers. Also the array of bolometers can be considered a single large detector and used for different purposes as the detection of solar axions or dark matter. 

Cryogenic detectors (calorimeters) were proposed in the 1980s by Fiorini and Niinikoski for searching rare events like neutrinoless double-beta decay ( 3 3-Ov) [52],... 

In the last decade, neutrino experiments have demonstrated that neutrinos are massive particles which may oscillate among three autostates. Such experiments [77-82] have evidenced the mass difference between the autostates, but not the neutrino mass scale value. The only way to determine the neutrino mass is the knowledge of the shape of the end point of energy spectrum in beta decays. In the hypothesis of the Majorana neutrino (neutrino coincides with antineutrino and its rest mass is different from zero), the measure of the decay half-life in the neutrinoless double-beta decay (DBD) would be necessary. A number of recent theoretical interpretations of neutrino oscillation experiments data imply that the effective Majorana mass of the electron neutrino (as measured in neutrinoless DBD) could be in the range 0.01 eV to the present bounds. 

The neutrino problem is described in the article on Particles (Subatomic), The double-beta decay event may contribute to the solution of that problem. In their introductory to the aforementioned article, the authors observe, The future of fundamental theories that account for everything from the building blocks of the atom to the architecture of the cosmos hinges on studies of this rarest of all observed radioactive events."... 

Avignone, F.T., III and R.I. Brodzinski A Review of Recent Developments in Double-Beta Decay, 21 (A. Faessler, Editor) Peigamon Press, 1988. 

Elliott. S.R.. A.A. Hahn, and K.M. Moe Direct Evidence for Two-Neutrino Double-Beta-Decay in Se," Physical Review Letters. 59, 18, pp. 2020-2023 (November 2, 1987). 

Masters. P.M. and M.R. Zimmerman Age Determination of an Alaskan Mummy Morphological and Biochemical Correlation." Science, 2U1. 811-812 (1978). Moe, M.K. and S.P. Rosen Double-Beta Decay," Sci. Amer.. 48 (November 1989). Monastersky. K. "Coral Corrects Carbon Daring Problems, Science News, 356 (June 9, i 990). 

Kirsten, T., Heusser, E., Kaether, D., Oehm, I, Pernicka, E., Richter, H. (1986) New geochemical double beta decay measurements on various selenium ores and remarks concerning tellurium isotopes. In Nuclear Beta Decays and Neutrino, T. Kotani, E. Ejiri, E. Takasugi, Eds., pp. 81-92. Singapore World Scientific. 

Podosek, F. A., Brannon, J. C., Bematowicz, J. T., Brazzle, R., Grauch, R., Cowsik, R., Hohenberg, C. M. (1994) Geochronology of tellurium ores and the double-beta decay lifetime of 130Te. In Noble Gas Geochemistry and Cosmochemistry, J. Matsuda, Ed., pp. 89-113, Tokyo Terra Scientific Publishing Co. 

The conversion of muonium (y+e ) to its antiatom antimuonium (y e+) would be an example of a muon number violating process,2 and like neutrinoless double beta decay would involve ALe=2. The M-M system also bears some relation to the K°-K7r system, since the neutral atoms M and M are degenerate in the absence of an interaction which couples them. In Table III a four-Fermion Hamiltonian term coupling M and M is postulated, and the probability that M formed at time t=0 will decay from the M mode is given. Present experimental limits22 23 for the coupling constant G are indicated and are larger than the Fermi constant Gp. 

Nuclear neutrino research includes neutrino experiments such as SNO, Super-Kamiokande, KamLAND, SAGE, and double-beta decay and theory of neutrino oscillations. 

The best limit for the half-life of neutrinoless double beta decay with Majoron emission is > 7.2 x 10 years (CL = 90%). 

Decay modes are a = alpha particle emission (B = negative beta emission p+ = positron emission EC = orbital electron capture IT = isomeric transition from upper to lower isomeric state n = neutron emission sf = spontaneous fission (B(B = double beta decay. Total disintegration energy in MeV units. 

In the year 2000 we measured the Ge double beta-decay value [11]. The measurement was motivated by the fact that there were two, seemingly conflicting, Q-values, both measured with a classical mass spectrometer by the Manitoba group, see reference [36,37] and Figure 6.9. 

FIGURE 6.9 double beta-decay Q-value deduced from Up triangle Ellis et al. [36],... 

Giioni L, Amaboldi C, Capelli S, Ciemonesi O, Pessina G, Piiro S et al (2009) CdW04 bolomeha Iot double beta decay search. Opt Matra- 31 1388-1392... 

---