The evidence for the observation of 0νββ decay:: The identification of 0νββ events from the full spectra

In this brief review, a description of the observed evidence for neutrinoless double beta(3-5) in the Ge-76 experiment in Gran Sasso (Heidelberg-Moscow experiment) which has been operated with 11 kg enriched Ge-76 detectors in the period 1990-2003, is provided. Two different methods of pulse shape analysis have been used to select potential 0 nu delta delta events from the gamma background of the measured spectrum - a selection by a neuronal net approach,(3,4,16) and a selection by a new method comparing measured pulses with a library of pulse shapes of point-like events calculated from simulation of the electric field distribution in the detectors (see Refs. 6-8 and 37). The latter method also allows spatial localization of measured events. Both methods lead to selections of events at Q beta beta with almost no gamma-background. The observed line at Q(beta beta) is identified as a O nu beta beta signal. It has a confidence level of more than 6 sigma.