Average and recommended half-life values for two neutrino double beta decay

Abstract

All existing positive results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{130}$Te, $^{136}$Xe, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm ($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te, and $^{130}$Ba are proposed. Given the measured half-life values, nuclear matrix elements were calculated using latest (more reliable and precise) values for phase space factor. Finally, previous results (PRC 81 (2010) 035501) were up-dated and results for $^{136}$Xe were added.