119086914
Supernova bound on keV-mass sterile neutrinos reexamined
Active-sterile neutrino mixing is strongly constrained for m_s > 100 keV to avoid excessive energy losses from supernova cores. For smaller m_s, matter effects suppress the effective mixing angle except for a resonant range of energies where it is enhanced. We study the case of \nu_tau-\nu_s-mixing where a \nu_tau-\bar\nu_tau asymmetry builds up due to the strong excess of \nu_s over \bar\nu_s emission or vice versa, reducing the overall emission rate. In the warm dark matter range m_s < 10 keV the mixing angle is essentially unconstrained.
119195344
The Minimal Type-II Seesaw Model and Flavor-dependent Leptogenesis
In this talk, we first give a brief review of the so-called minimal seesaw models and then concentrate on the minimal type-I seesaw model with two almost degenerate right-handed Majorana neutrinos of $\mathcal{O}(1 \,{\rm TeV})$. A specific texture of the neutrino Yukawa coupling matrix is proposed to achieve the nearly tri-bimaximal neutrino mixing pattern. This ansatz predicts (1) θ23 = π/4, |δ| = π/2 and sin2θ12 = (1 − 2tan2θ13)/3 in the m1 = 0 case; and (2) θ23 = π/4 and θ13 = 8 = 0 in the m3 = 0 case. In both cases, the cosmological baryon number asymmetry can be explained via the resonant leptogenesis mechanism. Finally, we demonstrate the significance of flavor-dependent effects in our leptogenesis scenario.
15493650
Why is the 3 x 3 neutrino mixing matrix almost unitary in realistic seesaw models
A simple extension of the standard model is to introduce n heavy right-handed Majorana, neutrinos and preserve its SU(2)(L) X U(1)(Y) gauge symmetry. Diagonalizing the (3 + n) x (3 + n) neutrino mass matrix, we obtain an exact analytical expression for the effective mass matrix of nu(e), nu(mu) and nu(tau). It turns out that the 3 x 3 neutrino mixing matrix V, which appears in the leptonic charged-current weak interactions, must not be exactly unitary. The unitarity violation of V is negligibly tiny, however, if the canonical seesaw mechanism works to reproduce the correct mass scale of light Majorana neutrinos. A similar conclusion can be drawn in the. realistic Type-II seesaw models.
118709874
Neutrinos in Particle Physics, Astronomy and Cosmology
Neutrinos: Past, Present and Future.- Neutrinos within the Standard Model.- Neutrinos beyond the Standard Model.- Phenomenology of Neutrino Oscillations.- Neutrinos from Stars.- Neutrinos from Supernovae.- Ultrahigh Energy Cosmic Neutrinos.- Neutrinos and Big Bang Nucleosynthesis.- Neutrinos and Cosmological Perburbations.- Neutrinos and Matter-Antimatter Asymmetry.- Other Topics of Neutrino Astrophysics.
118483859
The Minimal Seesaw Model at the TeV Scale
We point out that the minimal seesaw model can provide a natural framework to accommodate tiny neutrino masses, while its experimental testability and notable predictiveness are still maintained. T ...
119499848
Minimal type II seesaw model
We propose a minimal type II seesaw model by introducing only one right-handed neutrino besides the SU(2){sub L} triplet Higgs to the standard model. In the usual type II seesaw models with several right-handed neutrinos, the contributions of the right-handed neutrinos and the triplet Higgs to the CP asymmetry, which stems from the decay of the lightest right-handed neutrino, are proportional to their respective contributions to the light neutrino mass matrix. However, in our minimal type II seesaw model, this CP asymmetry is just given by the one-loop vertex correction involving the triplet Higgs, even though the contribution of the triplet Higgs does not dominate the light neutrino masses. For illustration, the Fritzsch-type lepton mass matrices are considered.
121896902
Meson spectrum in a non-relativistic model with instanton-induced interaction
On the basis of the phenomenological non-relativistic quark model, we have obtained the ground-state masses of the light pseudo-scalar and vector mesons. The full Hamiltonian used in the investigation includes the kinetic energy, the confinement potential, the one-gluon-exchange potential and the instanton-induced quark-antiquark interaction. A good agreement is obtained with the experimental masses. The eta-eta ' splitting is explained. The limitation of the perturbative treatment for estimating the pi-rho splitting using OGEP is also pointed out.
119227150
Nonaxial-octupole Y-32 correlations in N=150 isotones from multidimensional constrained covariant density functional theories
The nonaxial reflection-asymmetric beta(32) shape in some transfermium nuclei with N = 150, namely, Cm-246, Cf-248, Fm-250, and No-252, are investigated with multidimensional constrained covariant density functional theories. By using the density-dependent point-coupling covariant density functional theory with the parameter set DD-PC1 in the particle-hole channel, it is found that, for the ground states of Cf-248 and Fm-250, the nonaxial octupole deformation parameter beta(32) > 0.03 and the energy gain due to the beta(32) distortion is larger than 300 keV. In Cm-246 and No-252, shallow beta(32) minima are found. The occurrence of the nonaxial octupole beta(32) correlations is mainly from a pair of neutron orbitals, [734]9/2 (nu j(15/2)) and [622]5/2 (nu g(9/2)), which are close to the neutron Fermi surface, and a pair of proton orbitals, [521]3/2 (pi f(7/2)) and [633]7/2 (pi i(13/2)), which are close to the proton Fermi surface. The dependence of the nonaxial octupole effects on the form of the energy density functional and on the parameter set is also studied.
117347531
Gravitational waves from Affleck-Dine condensate fragmentation
We compute the stochastic gravitational wave production from Affleck-Dine condensate fragmentation in the early universe, focusing on an effective potential with a logarithmic mass correction that typically arises in gravity mediated supersymmetry breaking scenarios. We find that a significant gravitational wave background can be generated when Q-balls are being formed out of the condensate fragmentation. This gravitational wave background has a distinct multi-peak power spectrum where the trough is closely linked to the supersymmetry breaking scale and whose frequencies are peaked around kHz for TeV supersymmetry breaking.
18203445
Theoretical study of the two-proton halo candidate 17Ne including contributions from resonant continuum and pairing correlations
Abstract.With the relativistic Coulomb wave function boundary condition, the energies, widths and wave functions of the single-proton resonant orbitals for 17Ne are studied by the analytical continuation in the coupling constant (ACCC) approach within the framework of the relativistic mean field (RMF) theory. Pairing correlations and contributions from the single-particle resonant orbitals in the continuum are taken into consideration by the resonant Bardeen-Cooper-Schrieffer (BCS) approach, in which the constant pairing strength is used. It can be seen that the fully self-consistent calculations with NL3 and NLSH effective interactions mostly agree with the latest experimental measurements, such as binding energies, matter radii, charge radii and densities. The energy of the $ \pi2s_{1/2}$ orbital is slightly higher than that of the $ \pi1d_{5/2}$ orbital, and the occupation probability of the $ (\pi2s_{1/2})^2$ orbital is about 20%, which is in accordance with the shell model calculation and three-body model estimation.
119457636
Splitting of the pi-rho spectrum in a renormalized light-cone QCD-inspired model
We show that the splitting between the light pseudoscalar and vector meson states is due to the strong short-range attraction in the ${}^{1}{S}_{0}$ sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudoscalar ground state mass fixes the renormalized strength of the Dirac-delta interaction.