Vacuum polarization effects in hyperon-rich dense matter - a nonperturbative treatment

We derive the equation of state (EOS) for electrically charged neutral dense matter using the quantum hadrodynamics (QHD) model. This is carried out in a non-perturbative manner including quantum corrections for baryons through a realignment of vacuum with baryon-antibaryon condensates. This yields the results of relativistic Hartree approximation of summing over baryonic tadpole diagrams. The quantum corrections from the scalar meson is also taken into account in a similar way. This leads to a softening of the EOS for the hyperonic matter. The formalism also allows Lis to make a self-consistent calculation of the in-medium sigma meson mass. The effects of such quantum corrections on the composition of charged neutral dense matter is considered. The effect of the resulting EOS on the structure of neutron stars is also studied.

Ground state masses and binding energies of the nucleon, hyperon and heavy baryons in a light-front model

The ground state masses and binding energies of the nucleon, lambda0, lambdac+ , lambdab0 are studied within a constituent quark QCD-inspired light-front model. The light-front Faddeev equations for the Qqq composite spin 1/2 baryons, are derived and solved numerically. The experimental data for the masses are qualitatively described by a flavor independent effective interaction.

Nonmesonic weak decay dynamics from proton spectra of Lambda-hypernuclei

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

QCD sum rule approach to the s->d gamma contribution to the Omega(-)->Xi(-)gamma radiative decay

QCD sum rules are used to calculate the contribution of the short-distance single-quark transition s-->d gamma to the amplitudes of the hyperon radiative decay Omega(-)-->Xi(-) gamma. We reevaluate the Wilson coefficient of the effective operator responsible for this transition. We obtain a branching ratio which is comparable to the unitarity limit.