122144171
Giant halo at the neutron drip line in Ca isotopes in relativistic continuum Hartree-Bogoliubov theory
The properties of even-even O, Ca, Ni, Zr, Sn, and Pb isotopes from the beta-stability line to the neutron drip line are studied with the relativistic continuum Hartree-Bogoliubov theory, where both the spin-orbit interaction and continuum are properly taken into account. The available experimental binding energies E-b and two-neutron separation energies S-2n are reproduced very well. The predicted neutron drip-line nuclei are, respectively, Ca-74, Ni-100, Zr-140, Sn-176, and Pb-268. Based on the analysis of two-neutron separation energies, single-particle energy levels, the orbital occupation, the contribution of continuum and nucleon density distribution, giant halo phenomena due to pairing, correlation and the contribution from the continuum are suggested to appear in Ca isotopes with A>60 apart from Zr isotopes predicted earlier.
119220585
Systematic investigation of the rotational bands in nuclei with Z approximate to 100 using a particle-number conserving method based on a cranked shell model
The rotational bands in nuclei with Z approximate to 100 are investigated systematically by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are taken into account exactly. By fitting the experimental single-particle spectra in these nuclei, a new set of Nilsson parameters (kappa and mu) and deformation parameters (epsilon(2) and epsilon(4)) are proposed. The experimental kinematic moments of inertia for the rotational bands in even-even, odd-A, and odd-odd nuclei, and the band-head energies of the one-quasiparticle bands in odd-A nuclei, are reproduced quite well by the PNC-CSM calculations. By analyzing the omega dependence of the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions of valence orbitals in each major shell to the angular momentum alignment, the upbending mechanism in this region is understood clearly.
17321794
Relativistic continuum Hartree Bogoliubov theory for ground-state properties of exotic nuclei
The Relativistic Continuum Hartree-Bogoliubov (RCHB) theory, which properly takes into account the pairing correlation and the coupling to (discretized) continuum via Bogoliubov transformation in a microscopic and self-consistent way, has been reviewed together with its new interpretation of the halo phenomena observed in light nuclei as the scattering of particle pairs into the continuum, the prediction of the exotic phenomena - giant halos in nuclei near neutron drip line, the reproduction of interaction cross sections and charge-changing cross sections in light exotic nuclei in combination with the Glauber theory, better restoration of pseudo-spin symmetry in exotic nuclei, predictions of exotic phenomena in hypernuclei, and new magic numbers in superheavy nuclei, etc. Recent investigations on new effective interactions, the density dependence of the interaction strengths, the RMF theory on the Woods-Saxon basis, the single-particle resonant states, and the resonant BCS (rBCS) method for the pairing correlation, etc. are also presented in some detail. (c) 2005 Elsevier B.V. All rights reserved.
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.
119525752
First order shape transition and critical point nuclei in Sm isotopes from relativistic mean field approach
The critical point nuclei in Sm isotopes, which marks the first order phase transition between spherical U(5) and axially deformed shapes SU(3), have been investigated in the microscopic quadrupole constrained relativistic mean field (RMF) model plus BCS method with all the most used interactions, i.e., NL1, NL3, NLSH and TM1. The calculated potential energy surfaces show a clear shape transition for the even-even Sm isotopes with $N = 82\sim 96$ and the critical point nuclei are found to be $^{148}$Sm, $^{150}$Sm and $^{152}$Sm. Similar conclusions can also be drawn from the microscopic neutron and proton single particle spectra.
118563627
DEFORMED RELATIVISTIC HARTREE-BOGOLIUBOV MODEL FOR EXOTIC NUCLEI
A deformed relativistic Hartree-Bogoliubov (DRHB) model is developed aiming at a proper description of exotic nuclei, particularly deformed ones with large spatial extension. In order to give an adequate description of both the contribution of the continuum and the large spatial distribution in exotic nuclei, the DRHB equations are solved in a Woods-Saxon basis in which the radial wave functions have proper asymptotic behaviors at large distance from the nuclear center which is crucial for the formation of halo. The formalism and the numerical procedure of the DRHB model in a Woods-Saxon basis are briefly presented.
119226033
Impacts of the Higgs mass on vacuum stability, running fermion masses and two-body Higgs decays
The recent results of the ATLAS and CMS experiments indicate 116 GeV less than or similar to M-H less than or similar to 131 GeV and 115 GeV less than or similar to M-H less than or similar to 127 GeV, respectively, for the mass of the Higgs boson in the standard model (SM) at the 95% confidence level. In particular, both experiments point to a preferred narrow mass range M-H similar or equal to (124 . . . 126) GeV. We examine the impact of this preliminary result of M-H on the SM vacuum stability by using the two-loop renormalization-group equations, and arrive at the cutoff scale Lambda(VS) similar to 4 X 10(12) GeV (for M-H = 125 GeV, M-t = 172.9 GeV, and alpha(s)(M-Z) = 0.1184), where the absolute stability of the SM vacuum is lost and some kind of new physics might take effect. We update the values of running lepton and quark masses at some typical energy scales, including the ones characterized by M-H, 1 TeV and Lambda(VS), with the help of the two-loop renormalization-group equations. The branching ratios of some important two-body Higgs decay modes, such as H -> b (b) over bar, H -> tau(+)tau(-), H -> gamma gamma, H -> W+W-, and H -> ZZ, are also recalculated by inputting the values of relevant particle masses at M-H.
119243773
Goldstone's Theorem and Hamiltonian of Multi-galileon Modified Gravity
The Galileon model was recently proposed to locally describe a class of modified gravity theories, including the braneworld Dvali-Gabadadze-Porrati model. We discuss spontaneous symmetry breaking of the self-accelerating branch in a multi-Galileon theory with internal global symmetries. We show that a modified version of Goldstone's theorem is applicable to the symmetry breaking pattern and discuss its implications. We also derive the Hamiltonian of a general multi-Galileon theory and discuss its implications.
123125305
Relativistic astrophysics at GR20
We report the recent advances in Relativistic Astrophysics as presented at the GR20 meeting in Warsaw, Poland, in July 2013.
119352062
Tri-bimaximal neutrino mixing and flavor-dependent resonant leptogenesis
We propose a particularly economical neutrino mass model, in which there are only two right-handed Majorana neutrinos of O(l) TeV and their masses are highly degenerate. Its novel Yukawa-coupling texture together with the seesaw mechanism allows us to achieve the normal neutrino mass hierarchy with m(1) = 0 and a nearly tri-bimaiimal neutrino mixing pattern with the maximal CP-violating phase: theta(23) = pi/4, \delta\ = pi/2 and sin(2) theta(12) = (1 - 2tan(2) theta(13))/3. One may also obtain the inverted neutrino mass hierarchy with m(3) = 0 and the corresponding neutrino mixing pattern with theta(23) = pi/4 and theta(13) = delta = 0. In both cases, it is possible to interpret the cosmological baryon number asymmetry eta(B) approximate to 6.1 x 10(-10) through the resonant leptogenesis mechanism. We demonstrate the significance of flavor-dependent effects in this leptogenesis scenario: they can either flip the sign of the flavor-independent prediction for eta(B) in the m(1) = 0 case or magnify the magnitude of the flavor-independent prediction for eta(B) about 50 times in the m(3) = 0 case. (C) 2007 Elsevier BN. All rights reserved.
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.