H. F. Zhang

{alpha} particle preformation in heavy nuclei and penetration probability

The ensuremath{alpha} particle preformation in the even-even nuclei from

Branching ratios of {alpha} decay to excited states of even-even nuclei

^{108}mathrm{Te}

Theoretical and experimental {alpha} decay half-lives of the heaviest odd-Z elements and general predictions

to

Transport parameters in neutron stars from in-medium NN cross sections

{}^{294}

Proton radioactivity within a generalized liquid drop model

118 and the penetration probability have been studied. The isotopes from Pb to U have been firstly investigated since the experimental data allow us to extract the microscopic features for each element. The assault frequency has been estimated using classical methods and the penetration probability from tunneling through the Generalized Liquid Drop Model (GLDM) potential barrier. The preformation factor has been extracted from experimental ensuremath{alpha} decay energies and half-lives. The shell closure effects play the key role in the ensuremath{alpha} preformation. The more the nucleon number is close to the magic numbers, the more the formation of ensuremath{alpha} cluster is difficult inside the mother nucleus. The penetration probabilities reflect that 126 is a neutron magic number. The penetration probability range is very large compared to that of the preformation factor. The penetration probability determines mainly the ensuremath{alpha} decay half-life while the preformation factor allows us to obtain information on the nuclear structure. The study has been extended to the newly observed heaviest nuclei.

ROLE OF NUCLEONIC FERMI SURFACE DEPLETION IN NEUTRON STAR COOLING

Branching ratios of α-decay to members of the ground state rotational band and excited 0 states of even-even nuclei are calculated in the framework of the generalized liquid drop model (GLDM) by taking into account the angular momentum of the α-particle and the excitation probability of the daughter nucleus. The calculation covers isotopic chains from Hg to Fm in the mass regions 180 < A < 202 and A≥ 224. The calculated branching ratios of the α-transitions are in good agreement with the experimental data and some useful predictions are provided for future experiments.

Medium polarization and pairing in asymmetric nuclear matter

Theoretical {alpha} decay half-lives of the heaviest odd-Z nuclei are calculated using the experimental Q{sub {alpha}} value. The barriers in the quasimolecular shape path are determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The calculations provide consistent estimates for the half-lives of the {alpha} decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time. Predictions are provided for the {alpha} decay half-lives of other superheavy nuclei within the GLDM and VSS approaches using the recent extrapolated Q{sub {alpha}} of Audi, Wapstra, and Thibault [Nucl. Phys. A729, 337 (2003)], which may be used for future experimental assignment and identification.

Weizsäcker–Skyrme-type mass formula by considering radial basis function correction

We present a numerical study of shear viscosity and thermal conductivity of symmetric nuclear matter, pure neutron matter, and beta-stable nuclear matter, in the framework of the Brueckner theory. The calculation of in-medium cross sections and nucleon effective masses is performed with a consistent two- and three-body interaction. The investigation covers a wide baryon density range as needed in the applications to neutron stars. The results for the transport coefficients in beta-stable nuclear matter are used to make preliminary predictions on the damping time scales of nonradial modes in neutron stars.

Fine structure of alpha decay to rotational states of heavy nuclei

The proton radioactivity half-lives of spherical proton emitters are investigated theoretically. The potential barriers preventing the emission of protons are determined in the quasimolecular shape path within a generalized liquid drop model (GLDM) including the proximity effects between nuclei in a neck and the mass and charge asymmetry. The penetrability is calculated with the WKB approximation. The spectroscopic factor has been taken into account in half-life calculation, which is obtained by employing the relativistic mean field (RMF) theory combined with the BCS method with the force NL3. The half-lives within the GLDM are compared with the experimental data and other theoretical values. The GLDM works quite well for spherical proton emitters when the spectroscopic factors are considered, indicating the necessity of introducing the spectroscopic factor and the success of the GLDM for proton emission. Finally, we present two formulas for proton emission half-life calculation similar to the Viola-Seaborg formulas and Royers formulas of {alpha} decay.

Analytic expressions for alpha particle preformation in heavy nuclei

The Fermi surface depletion of beta-stable nuclear matter is calculated to study its effects on several physical properties which determine the neutron star thermal evolution. The neutron and proton Z factors measuring the corresponding Fermi surface depletions, are calculated within the Brueckner-Hartree-Fock approach employing the AV18 two-body force supplemented by a microscopic three body force. Neutrino emissivity, heat capacity and, in particular, neutron 3PF2 superfluidity turn out to be reduced, especially at high baryonic density, to such an extent that the cooling rates of young neutron stars are significantly slowed