[en] In the present work, we have been restricted to (β⁺β⁺)_0v and (εβ⁺)_0v modes of ⁹⁶Ru, ¹⁰²Pd, ¹⁰⁶Cd, ¹²⁴Xe, ¹³⁰Ba and ¹⁵⁶Dy isotopes for the 0⁺ →⁺0^- transition

[en] The purpose of the present electrical signal path study is to explore the various issues related to the deployment of highly-segmented low-background Ge detectors for the MAJORANA double-beta decay experiment. A significant challenge is to simultaneously satisfy competing requirements for the mechanical design, electrical readout performance, and radiopurity specifications from the MAJORANA project. Common to all rare search experiments, there is a very stringent limit on the acceptable radioactivity level of all the electronics components involved. Some of the findings are summarized in this report.

[en] A brief review of several theoretical and experimental talks related to the double-beta decay which were moderated by the author during the workshop MEDEX'99. Comments and criticisms made by some participants in the round table session are also included. (author)

No abstract available

[en] Three open problems in neutrino physics are mentioned. A brief review of neutrino- less double beta decay (DBD) is given. The question of quenching of g_A is discussed. Other possible scenarios, Majoron emission, sterile neutrinos and non-standard mechanisms, are presented and their implication to DBD discussed. (paper)

[en] The nuclear matrix elements of Majorana neutrino mass mechanism of neutrinoless double-beta decay have so far been calculated using only contributions from vector axial-vector part and weak magnetism of the nuclear current, while other contributions have been neglected. In the present work we are examining the effect of weak magnetism and induced pseudoscalar coupling. We have performed calculations within the proton-neutron renormalized quasiparticle random phase approximation and we have found that these additional contributions of the nucleon current, result in a considerable reduction of the nuclear matrix elements of all nuclei which we have considered. This reduction of the nuclear matrix element makes the extracted limits of the lepton number violating parameters (ν> and <η_N>) and less stringent yielding the best value for less than 0.51 eV for ^76Ge. (author)

[en] Summary of the talks presented on the fourth day of the Workshop on calculation of double-beta-decay matrix elements, MEDEX'99, and conclusions based on questions of the audience and the ensuing round-table discussion. (author)

No abstract available

[en] The most recent development in the calculations of the nuclear matrix elements for the two neutrino double beta decay are reviewed. In particular the progress connected with application of the renormalized quasiparticle random phase approximation is summarized. This new technique was proposed to describe the relevant matrix elements for the 2ν2ββ-decay of ⁷⁶Ge to the ground 0⁺- and first excited 2⁺ -states in ⁷⁶Se. We have shown, that most of the g_pp dependence of the matrix element can be removed by the inclusion of the Pauli principle in the QRPA-calculations. The matrix element remains stable in the physical region of g_pp and would thus allow to reduce limits of the decay. (orig.)

[en] Constraints on neutrino mixing parameters are extracted from results of neutrinoless double beta decay experiments and displayed as allowed regions on the m_l-cos2Θ₁₂ plane. For example, 0.05 eV(0eV) < or approx. m_l < or approx. 1.85 eV is obtained for the normal (inverted) hierarchy by using the LMA best fit parameters and the 0νββ result announced late 2001