669 research outputs found

    On nuclear matrix element uncertainties in short range 0vBB decay

    Full text link
    The evaluation of short range contributions to neutrinoless double beta decay has been challenged due to critics of the ansatz of the nuclear matrix element calculations. We comment on the critics and uncertainties of these calculations and the effect on the derived limits.Comment: 3 pages, Latex, new arguments adde

    Double beta decay versus cosmology: Majorana CP phases and nuclear matrix elements

    Full text link
    We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana CP phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half life. Consequently, one of the Majorana CP phases can be constrained when combining the claimed evidence for neutrinoless double beta decay with the neutrino mass bound from cosmology.Comment: 11 pages, 3 figure

    In-Medium Similarity Renormalization Group with Chiral Two- Plus Three-Nucleon Interactions

    Full text link
    We use the recently proposed In-Medium Similarity Renormalization Group (IM-SRG) to carry out a systematic study of closed-shell nuclei up to \nuc{Ni}{56}, based on chiral two- plus three-nucleon interactions. We analyze the capabilities of the IM-SRG by comparing our results for the ground-state energy to Coupled Cluster calculations, as well as to quasi-exact results from the Importance-Truncated No-Core Shell Model. Using chiral two- plus three-nucleon Hamiltonians whose resolution scales are lowered by free-space SRG evolution, we obtain good agreement with experimental binding energies in \nuc{He}{4} and the closed-shell oxygen isotopes, while the calcium and nickel isotopes are somewhat overbound.Comment: 11 pages, 7 figures, submitted to Phys. Rev.

    Collectivity-induced quenching of signatures for shell closures

    Full text link
    Mass differences are an often used as signature and measure for shell closure. Using the angular-momentum projected Generator Coordinate Method and the Skyrme interaction SLy4, we analyze the modification of mass differences due to static deformation and dynamic fluctuations around the mean-field ground state.Comment: 7 pages, 4 figure

    Smartphone Use in Financial Management among Women’s Informal Saving Groups in Dodoma, Tanzania

    Get PDF
    Diffusion of smartphone technology has created multiple opportunities for economic development. This research investigated the use of smartphones in financial management among women’s informal saving groups in Dodoma, Tanzania. Qualitative data were collected from 10 groups, derived from 15 interviews and 3 focus group discussions (FGDs) with 22 participants and thematic analysis was done. The findings revealed that research participants were using smartphones to access WhatsApp, the camera, mobile money applications and the calculator for coordination, recording, calculation, and payment. It was also found that untrustworthy communications, high charges and mobile fraud were challenges experienced by the groups. Familiarity, ease of use and nature of the group were identified as important reasons for the smartphone use in financial management. The research contributes knowledge regarding digitizing informal saving groups although smartphone use was not strongly linked to financial management success. This suggests a need for improved skills and technological empowerment to achieve sustainable growth

    Nuclear matrix element for two neutrino double beta decay from 136Xe

    Full text link
    The nuclear matrix element for the two neutrino double beta decay (DBD) of 136Xe was evaluated by FSQP (Fermi Surface Quasi Particle model), where experimental GT strengths measured by the charge exchange reaction and those by the beta decay rates were used. The 2 neutrino DBD matrix element is given by the sum of products of the single beta matrix elements via low-lying (Fermi Surface) quasi-particle states in the intermediate nucleus. 136Xe is the semi-magic nucleus with the closed neutron-shell, and the beta + transitions are almost blocked. Thus the 2 neutrino DBD is much suppressed. The evaluated 2 neutrino DBD matrix element is consistent with the observed value.Comment: 7 pages 6 figure

    Influence of interspecific interference competition on the genetic structure of Calopteryx splendens populations

    Get PDF
    Understanding the effects of interspecific competition on genetic diversity will deepen our knowledge on species evolution. In the case of Calopteryx splendens and C. virgo, sympatric damselfly species, interspecific interference competition by C. virgo has remarkable effects on territoriality of C. splendens resulting in reproductive character displacement. Since territoriality is correlated with phenotype and mating success, we investigated the effects of interspecific interference competition on genetic diversity of C. splendens populations. Using amplified fragment length polymorphisms (AFLP), we determined the population genetic structure of 12 C. splendens populations and used the genetic diversity information to relate heterozygosity of C. splendens to abundance of C. virgo in sympatric populations. We found that heterozygosity of C. splendens males decreased with increasing abundance of C. virgo males. This result most likely reflects changes in effective population size due to interspecific interference competition and shows an effect on genetic structure in damselfly populations.</p

    Neutrinoless Double Beta Decay within QRPA with Proton-Neutron Pairing

    Get PDF
    We have investigated the role of proton-neutron pairing in the context of the Quasiparticle Random Phase approximation formalism. This way the neutrinoless double beta decay matrix elements of the experimentally interesting A= 48, 76, 82, 96, 100, 116, 128, 130 and 136 systems have been calculated. We have found that the inclusion of proton-neutron pairing influences the neutrinoless double beta decay rates significantly, in all cases allowing for larger values of the expectation value of light neutrino masses. Using the best presently available experimental limits on the half life-time of neutrinoless double beta decay we have extracted the limits on lepton number violating parameters.Comment: 16 RevTex page

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

    Full text link
    After analysis of 5797 h of data from the detector NEMO3, new limits on neutrinoless double beta decay of Mo-100 (T_{1/2} > 3.1 10^{23} y, 90% CL) and Se-82 (T_{1/2} > 1.4 10^{23} y, 90% CL) have been obtained. The corresponding limits on the effective majorana neutrino mass are: m < (0.8-1.2) eV and m < (1.5-3.1) eV, respectively. Also the limits on double-beta decay with Majoron emission are: T_{1/2} > 1.4 10^{22} y (90% CL) for Mo-100 and T_{1/2}> 1.2 10^{22} y (90%CL) for Se-82. Corresponding bounds on the Majoron-neutrino coupling constant are g < (0.5-0.9) 10^{-4} and < (0.7-1.6) 10^{-4}. Two-neutrino 2b-decay half-lives have been measured with a high accuracy, T_{1/2} Mo-100 = [7.68 +- 0.02(stat) +- 0.54(syst) ] 10^{18} y and T_{1/2} Se-82 = [10.3 +- 0.3(stat) +- 0.7(syst) ] 10^{19} y.Comment: 5 pages, 4 figure
    • …
    corecore