Wed·Feb 17, 2016Wednesday·February 17, 2016

1. 01*

   Occupation numbers of spherical orbits in self-consistent beyond-mean-field methods

   Tomás R. Rodríguez🇪🇸 · Alfredo Poves🇪🇸 · Frédéric Nowacki🇫🇷

   We present a method to compute the number of particles occupying spherical single-particle (SSP) levels within the energy density functional (EDF) framework. These SSP levels are defined for each nucleus by performing self-consistent mean-field calculations. The nuclear many-body states, in which the occupation numbers are evaluated, are obtained with a symmetry conserving configuration mixing (SCCM) method based on the Gogny EDF. The method allows a closer comparison between EDF and shell model with configuration mixing in large valence spaces (SM-CI) results, and can serve as a guidance to define physically sound valence spaces for SM-CI calculations. As a first application of the method, we analyze the onset of deformation in neutron-rich $N=40$ isotones and the role of the SSP levels around this harmonic oscillator magic number, with particular emphasis in the structure of ${}^{64}$Cr.

   ↳ nucl-thnucl-exPRC(2016)·21 citations
2. 02*

   A Relativistic Model for the Electromagnetic Structure of Baryons from the 3rd Resonance Region

   G. Ramalho🇧🇷

   We present some predictions for the ${\gamma }^{\ast }N\to N^{\ast }$ transition amplitudes, where $N$ is the nucleon, and $N^{\ast }$ is a nucleon excitation from the third resonance region. First we estimate the transition amplitudes associated with the second radial excitation of the nucleon, interpreted as the $N(1710)$ state, using the covariant spectator quark model. After that, we combine some results from the covariant spectator quark model with the framework of the single quark transition model, to make predictions for the ${\gamma }^{\ast }N\to N^{\ast }$ transition amplitudes, where $N^{\ast }$ is a member of the $SU(6)$-multiplet $[70,1^{-}]$. The results for the ${\gamma }^{\ast }N\to N(1520)$ and ${\gamma }^{\ast }N\to N(1535)$ transition amplitudes are used as input to the calculation of the amplitudes $A_{1/2}$, $A_{3/2}$, associated with the ${\gamma }^{\ast }N\to N(1650)$, ${\gamma }^{\ast }N\to N(1700)$, ${\gamma }^{\ast }N\to \Delta (1620)$, and ${\gamma }^{\ast }N\to \Delta (1700)$ transitions. Our estimates are compared with the available data. In order to facilitate the comparison with future experimental data at high $Q^2$, we derived also simple parametrizations for the amplitudes, compatible with the expected falloff at high $Q^2$.

   ↳ hep-phhep-exnucl-exnucl-thFew Body Syst.(2016)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.