Proton rich nuclei at and beyond the proton drip line in the Relativistic Mean Field theory

Ground state properties of proton-rich odd-$Z$ nuclei in the region $55\le Z \le 73$ are studied in the relativistic mean field (RMF) theory. The RMF equations are solved by using the expansion method in the Harmonic-Oscillator basis. In the particle-particle channel, we use the state-dependent BCS method with a zero-range $\delta$-force, which has been proved to be effective even for neutron-rich nuclei. All the ground state properties, including the one-proton separation energies, the ground state deformations, the last occupied proton orbits and the locations of proton drip line, are calculated. Good agreement with both the available experimental data and the predictions of the RHB method are obtained.Comment: the version to appear in Progress of Theoretical Physics, more discussions adde

Masses, Deformations and Charge Radii--Nuclear Ground-State Properties in the Relativistic Mean Field Model

We perform a systematic study of the ground-state properties of all the nuclei from the proton drip line to the neutron drip line throughout the periodic table employing the relativistic mean field model. The TMA parameter set is used for the mean-field Lagrangian density, and a state-dependent BCS method is adopted to describe the pairing correlation. The ground-state properties of a total of 6969 nuclei with $Z,N\ge 8$ and $Z\le 100$ from the proton drip line to the neutron drip line, including the binding energies, the separation energies, the deformations, and the rms charge radii, are calculated and compared with existing experimental data and those of the FRDM and HFB-2 mass formulae. This study provides the first complete picture of the current status of the descriptions of nuclear ground-state properties in the relativistic mean field model. The deviations from existing experimental data indicate either that new degrees of freedom are needed, such as triaxial deformations, or that serious effort is needed to improve the current formulation of the relativistic mean field model.Comment: 16 pages, 5 figures, to appear in Progress of Theoretical Physic

A systematic study of neutron magic nuclei with N = 8, 20, 28, 50, 82, and 126 in the relativistic mean field theory

We perform a systematic study of all the traditional neutron magic nuclei with $N$ = 8, 20, 28, 50, 82, and 126, from the neutron drip line to the proton drip line. We adopt the deformed relativistic mean field (RMF) theory as our framework and treat pairing correlations by a simple BCS method with a zero-range $\delta$-force. Remarkable agreement with the available experimental data is obtained for the binding energies, the two- and one-proton separation energies, and the nuclear charge radii. The calculated nuclear deformations are compared with the available experimental data and the predictions of the FRDM mass formula and the HFBCS-1 mass formula. We discuss, in particular, the appearance of sub-shell magic nuclei by observing irregular behavior in the two- and one-proton separation energies.Comment: the version to appear in Journal of Physics G; more references adde

Relativistic mean field theory for deformed nuclei with pairing correlations

We develop a relativistic mean field (RMF) description of deformed nuclei with the pairing correlations in the BCS approximation. The treatment of the pairing correlations for nuclei with the Fermi surface being close to the threshold of unbound states needs a special attention. To this end, we take the delta function interaction for the pairing interaction with the hope to pick up those states with the wave function being concentrated in the nuclear region and perform the standard BCS approximation for the single particle states generated by the RMF theory with deformation. We apply the RMF + BCS method to the Zr isotopes and obtain a good description of the binding energies and the nuclear radii of nuclei from the proton drip line to the neutron drip line.Comment: the version to be published in Progress of Theoretical Physic

Octet baryon masses in next-to-next-to-next-to-leading order covariant baryon chiral perturbation theory

We study the ground-state octet baryon masses and sigma terms using the covariant baryon chiral perturbation theory (ChPT) with the extended-on-mass-shell (EOMS) renormalization scheme up to next-to-next-to-next-to-leading order (N$^3$LO). By adjusting the available 19 low-energy constants (LECs), a reasonable fit of the $n_f=2+1$ lattice quantum chromodynamics (LQCD) results from the PACS-CS, LHPC, HSC, QCDSF-UKQCD and NPLQCD collaborations is achieved. Finite-volume corrections to the lattice data are calculated self-consistently. Our study shows that N$^3$LO BChPT describes better the light quark mass evolution of the lattice data than the NNLO BChPT does and the various lattice simulations seem to be consistent with each other. We also predict the pion and strangeness sigma terms of the octet baryons using the LECs determined in the fit of their masses. The predicted pion- and strangeness-nucleon sigma terms are $\sigma_{\pi N}=43(1)(6)$ MeV and $\sigma_{s N}=126(24)(54)$ MeV, respectively.Comment: 28 pages, 6 figures, minor revisions, typos corrected, version to appear in JHE

Study of pesudoscalar transition form factors within light front quark model

We study the transition form factors of the pesudoscalar mesons ($\pi,\eta$ and $\eta^{\prime}$) as functions of the momentum transfer $Q^2$ within the light-front quark model. We compare our results with the recent experimental data by CELLO, CLEO, BaBar and Belle. By considering the possible uncertainties from the quark masses, we illustrate that our predicted form factors can fit with all the data, including those at the large $Q^2$ regions.Comment: 10 pages, 4 figures, accepted for publication in Phys. Rev.

Clues for the existence of two K1(1270)K_1(1270) resonances

The axial vector meson $K_1(1270)$ was studied within the chiral unitary approach, where it was shown that it has a two-pole structure. We reanalyze the high-statistics WA3 experiment $K^- p\to K^-\pi^+\pi^- p$ at 63 GeV, which established the existence of both $K_1(1270)$ and $K_1(1400)$, and we show that it clearly favors our two-pole interpretation. We also reanalyze the traditional K-matrix interpretation of the WA3 data and find that the good fit of the data obtained there comes from large cancellations of terms of unclear physical interpretation.Comment: published version in PRD; typos corrected; title changed to "Clues for the existence of two $K_1(1270)$ resonances