The observation of neutrinoless double beta decay (DBD) will have important consequences. Though simple qualitative arguments imply that the electron coincidence spectra for two-neutrino, and for no-neutrino double β-decay are broadly peaked at ½E 0 and infinitely sharply peaked at E 0 respectively (E 0 is the energy release), a recent calculation has shown that in some circumstances the two-neutrino case spectrum may also be broadly peaked in the region of E 0. Radioactivity was discovered in 1896 by Henri Becquerel in uranium, and subsequently observed by Marie and Pierre Curie in thorium and in the new elements polonium and radium. 40K is also contained in liquid scintillator. happens when a single beta decay cannot happen because the would-be daughter Z+1 nucleus has a higher energy than the original Z nucleus, but the Z+2 daughter has a lower energy. The key scales of mee, which will lead to the discrimination among various schemes are: mee ∼ 0.1 eV and mee ∼ 0.005 eV. Copyright © 2011 NEXT Collaboration. Beta Decay 2 with the Tables for the Analysis of Beta Spectra produced by the National Bureau of Standards. The detection of the neutrino accompanied mode ... endpoint energy of the electron spectrum in tritium beta decay. If neutrinos are their own antiparticles, i.e., Majorana particles, NLDBD process can happen. Figure 1: Beta decay spectrum. The most sensitive probe for the Majorana nature of neutrinos is an extremely rare nuclear decay process called neutrinoless double beta decay ($$0\nu \beta \beta$$), where a nucleus with mass number A and charge Z decays by emitting only two electrons and changes its charge by two units (A,Z)$$\longrightarrow$$(A,Z+2) + 2e$$^{-}$$. (b) 2 2 and 0 2 spectrum. Second, it represents our best hope for determining the absolute neutrino … In a typical double beta decay, two neutrons in the nucleus are converted to protons, and two electrons and two electron antineutrinos are emitted. Reproduced from [4]. 5.1 Double beta decay (2 2 ) Some nuclei can only decay trough double beta decay, which was proposed by Maria Goeppert Mayer in 1935. If N(p)is the probability that an electron is emitted with momentum betweenp and p+dp, then, if the neutrino is massless we have: N(p)=CF(Z,p)p2(E 0 − E e)2 where C is a collection of constants. No candidate events for the zero-neutrino double beta decay during 21 924 h results in a half-life limit of 2.7×1022 years at the 68% confidence level. Juan José Gómez Cadenas (IFIC, Valencia) and David Nygren (Arlington, Texas) are co-spokespersons. SEARCH FOR THE DOUBLE BETA DECAY OF Nd 5 USING A MAGNETIC SPECTROMETER­DETECTOR Abstract by GARY R. SMITH A large aperture, low resolution magnetic ' spectrometer­detector was designed and constructed to search for the double "beta decay of Nd . 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