Double beta decay
The problem of double beta decay is reviewed with emphasis on its relevance to lepton number conservation. Recently, the ratio of the double beta-decay half-lives of /sup 128/Te and /sup 130/Te has been measured in a geological experiment and a limit for the ratio of the neutrinoless rate to the total rate for /sup 82/Se decay has been obtained from a direct-detection experiment. For the first time, these results show conclusively that double beta decay is not primarily a lepton-number-violating neutrinoless process. However, they also do not agree with calculations which assume that only lepton-number-conserving two-neutrino double beta decay occurs. The conclusion that lepton number conservation is violated is suggested by limited experimental information. By considering contributions to the total rate from both the two-neutrino and the neutrinoless channels, we obtain data which are consistent with a lepton nonconservation parameter of order eta=3.5 x 10/sup -5/. Roughly the same value of eta is obtained by assuming that the decay occurs either via lepton emission from two nucleons or via emission from a resonance in the nucleus.
- Research Organization:
- TRIUMF, University of British Columbia, Vancouver, Canada, V6T 1W5
- OSTI ID:
- 6985668
- Journal Information:
- Rev. Mod. Phys.; (United States), Vol. 50:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BETA DECAY
REVIEWS
LEPTON NUMBER
CONSERVATION LAWS
TELLURIUM 130
TELLURIUM 128
SELENIUM 82
ELECTRON NEUTRINOS
HALF-LIFE
V-A THEORY
WEAK INTERACTIONS
XENON 130
XENON 128
KRYPTON 82
BASIC INTERACTIONS
DECAY
DOCUMENT TYPES
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FERMIONS
INTERACTIONS
INTERMEDIATE MASS NUCLEI
ISOTOPES
KRYPTON ISOTOPES
LEPTONIC DECAY
LEPTONS
MASSLESS PARTICLES
NEUTRINOS
NUCLEI
PARTICLE DECAY
SELENIUM ISOTOPES
STABLE ISOTOPES
TELLURIUM ISOTOPES
WEAK PARTICLE DECAY
XENON ISOTOPES
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