96 research outputs found
Non-collapsing renormalized QRPA with proton-neutron pairing for neutrinoless double beta decay
Using the renormalized quasiparticle random phase approximation (RQRPA), we
calculate the light neutrino mass mediated mode of neutrinoless double beta
decay of Ge76, Mo100, Te128 and Te130. Our results indicate that the simple
quasiboson approximation is not good enough to study the neutrinoless double
beta decay, because its solutions collapse for physical values of g_pp. We find
that extension of the Hilbert space and inclusion of the Pauli Principle in the
QRPA with proton-neutron pairing, allows us to extend our calculations beyond
the point of collapse, for physical values of the nuclear force strength. As a
consequence one might be able to extract more accurate values on the effective
neutrino mass by using the best available experimental limits on the half-life
of neutrinoless double beta decay.Comment: 15 pages, RevTex, 2 Postscript figures, to appear in Phys. Lett.
Neutrino reactions via neutral and charged current by Quasi-particle Random Phase Approximation(QRPA)
We developed the quasi-particle random phase approximation (QRPA) for the
neutrino scattering off even-even nuclei via neutral current (NC) and charged
cur- rent (CC). The QRPA has been successfully applied for the \beta and
\beta\beta decay of relevant nuclei. To describe neutrino scattering, general
multipole transitions by weak interactions with a finite momentum transfer are
calculated for NC and CC reaction with detailed formalism. Since we consider
neutron-proton (np) pairing as well as neutron-neutron (nn) and proton-proton
(pp) pairing correlations, the nn + pp QRPA and np QRPA are combined in a
framework, which enables to describe both NC and CC reactions in a consistent
way. Numerical results for \nu-^{12}C, -^{56}Fe and -^{56}Ni reactions are
shown to comply with other theoretical calculations and reproduce well
available experimental data
Ambiguities of neutrino(antineutrino) scattering on the nucleon due to the uncertainties of relevant strangeness form factors
Strange quark contributions to neutrino(antineutrino) scattering are
investigated on the nucleon level in the quasi-elastic region. The incident
energy range between 500 MeV and 1.0 GeV is used for the scattering. All of the
physical observable by the scattering are investigated within available
experimental and theoretical results for the strangeness form factors of the
nucleon. In specific, a newly combined data of parity violating electron
scattering and neutrino scattering is exploited. Feasible quantities to be
explored for the strangeness contents are discussed for the application to
neutrino-nucleus scattering.Comment: 17 pages, 7 figures, submit to J. Phys.
Neutrinoless Double Beta Decay within QRPA with Proton-Neutron Pairing
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
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