Measurement of the double-β decay of 150Nd to the 01+ excited state of 150Sm in NEMO-3

The NEMO-3 results for the double-beta decay of150Nd to the 0+1and 2+1excited states of150Sm are reported The data recorded during 5.25 year with 36.6 g of the iso-tope150Nd are used in the analysis. The signal of the 2 nu beta beta transition to the 0+1excited state is detected with a statisti-cal significance exceeding 5 sigma. The half-life is measured tobeT(1/2)(0 nu beta beta)((0+1)=[1.11+0.19-0.14(stat)+0.17-0.15(syst)]x10(20 )year, which is the most precise value that has been measuredto date. 90% confidence-level limits are set for the otherdecay modes. For the 2 nu beta beta decay to the 2+1level the limitisT2 nu beta beta 1/2(2+1)>2.42x10 (20 )year. The limits on the 0 nu beta beta decay to the 0+1and 2+1levels of150Sm are significantlyimproved toT0 nu beta beta 1/2(0+1)>1.36x1022year and T-1/2(0 nu beta beta)(2+1)>1.26x10(22)year

Automated summary

The NEMO-3 experiment reports the results of the double-beta decay of 150Nd to the 0+1 and 2+1 excited states of 150Sm. The signal of the 2 nu beta beta transition to the 0+1 excited state is detected with a statistical significance exceeding 5 sigma, and the half-life is measured to be [1.11+0.19-0.14(stat)+0.17-0.15(syst)]x10(20) years, the most precise value obtained to date. Limits are also set for other decay modes.