Journal of Physics. G, Nuclear and Particle Physics, 2015 vol. 42 no. 11
Agostini M. et al. (GERDA Collaboration) M. Wójcik, G. Zuzel, K. Pelczar, K. Panas, M. Misiaszek, N. Frodyma, D. Borowicz
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http://iopscience.iop.org/article/10.1088/0954-3899/42/11/115201
Abstract
Two neutrino double beta decay of 76-Ge to excited states of 76-Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in 76-Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation γ ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90% C.L. bounds for three transitions: