PaperPanorama
FAQ

Nuclear Theory·nucl-th

Monday·June 22, 2015

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule

    Ian C. Cloët🇺🇸 · Wolfgang Bentz🇯🇵 · Anthony W. Thomas🇦🇺

    In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.

    nucl-thhep-phnucl-exPRL(2016)·40 citations
  3. 03

    The Hypercentral Constituent Quark Model

    M.M. Giannini🇮🇹 · E. Santopinto🇮🇹

    The hypercentral Constituent Quark Model is presented and its application to the description of the electromagnetic properties of baryons is reviewed. The results concerning the elastic nucleon form factors and the electromagnetic excitation of baryon resonances are compared with the recent experimental data

    nucl-thAIP Conf.Proc.(2012)·6 citations
  4. 04

    Quark Model Calculations of the N to Delta Reaction

    M.M. Giannini🇮🇹

    The electromagnetic excitation of the nucleon resonances is studied in the framework of Constituent Quark Models. Particular attention is devoted to the transition to the resonance and to the issue of a possible deformation of hadronic systems, mainly in connection with the problem of the quadrupole excitation. The analysis of the emerging discrepancies between data and theoretical predictions is discussed and shown to lead to important conclusions concerning the internal dynamical structure of hadrons.

    nucl-thAIP Conf.Proc.(2007)·2 citations
  5. 05

    Subtraction method in the second random--phase approximation: first applications with a Skyrme energy functional

    D. Gambacurta🇮🇹 · M. Grasso🇫🇷 · J. Engel🇺🇸

    We make use of a subtraction procedure, introduced to overcome double--counting problems in beyond--mean--field theories, in the second random--phase--approximation (SRPA) for the first time. This procedure guarantees the stability of SRPA (so that all excitation energies are real). We show that the method fits perfectly into nuclear density--functional theory. We illustrate applications to the monopole and quadrupole response and to low--lying and states in the nucleus O. We show that the subtraction procedure leads to: (i) results that are weakly cutoff dependent; (ii) a considerable reduction of the SRPA downwards shift with respect to the random--phase approximation (RPA) spectra (systematically found in all previous applications). This implementation of the SRPA model will allow a reliable analysis of the effects of 2 particle--2 hole configurations () on the excitation spectra of medium--mass and heavy nuclei.

    nucl-thnucl-exPRC(2015)·73 citations

Affiliations

first authorsco-authorsvia INSPIRE