New experimental results on double beta decay of Te-130

New results are presented of a search for double beta decay of Te isotopes carried out, using the bolometric technique, with an array of 20 natural te llurite crystals with a total cryogenic mass of similar to 6.8 kilograms. T he array has been run at a temperature around 10 mK in the Gran Sasso Under ground Laboratory. No evidence has been found for neutrinoless double beta decay of Te-128 and Te-130 and upper limits of 8.6 x 10(22) and 1.44 x 10(2 3) years, respectively, have been achieved at the 90% confidence level. Fro m the latter we obtain limits on the lepton non-conserving parameters which are the most restrictive ones in direct experiments after those on Ge-76 a ccording to theoretical calculations. Results on two neutrino and majoron m ediated decays are also presented and discussed with respect to those obtai ned for the same nuclei in geochemical experiments. (C) 2000 Elsevier Scien ce B.V. All rights reserved.