Study of 2β-decay of ¹⁰⁰Mo and ⁸²Se using the NEMO3 detector

After analysis of 5797 h of data from the detector NEMO3, new limits on neutrinoless double beta decay of (100)Mo (T(1/2) > 3.1 x 10(23) y, 90% CL) and (82)Se (T(1/2) > 1.4 x 10(23) y, 90% CL) have been obtained. The corresponding limits on the effective majorana neutrino mass are: < (0.8-1.2) eV and < (1.5-3.1) eV, respectively. Also the limits on double-beta decay with Majoron emission are: T(1/2) > 1.4 x 10(22) y (90% CL) for (100)Mo and T(1/2) > 1.2 x 10(22) y (90% CL) for (82)Se. Corresponding bounds on the Majoron-neutrino coupling constant are < (0.5-0.9) x 10(- 4) and <(0.7-1.6) x 10(- 4). Two-neutrino 2beta-decay half-lives have been measured with a high accuracy, T(1/2)(100)Mo = [7.68 +/- 0.02(stat) +/- 0.54(syst)] x 10(18) y and T(1/2)(82)Se = [10.3 +/- 0.3(stat) +/- 0.7(syst)] x 10(19) y. (C) 2004 MAIK "Nauka/Interperiodica".