Nuclear Theory·nucl-th

Friday·May 12, 2017

3 papers—3 primary·0 cross-listed

01
[Submitted on 11 May 2017]
Parity partners in the baryon resonance spectrum
Ya Lu🇨🇳 · Chen Chen🇧🇷 · Craig D. Roberts🇺🇸 · Jorge Segovia🇩🇪 · Shu-Sheng Xu🇨🇳 · Hong-Shi Zong🇨🇳
We describe a calculation of the spectrum of flavour-SU(3) octet and decuplet baryons, their parity partners, and the radial excitations of these systems, made using a symmetry-preserving treatment of a vector-vector contact interaction as the foundation for the relevant few-body equations. Dynamical chiral symmetry breaking generates nonpointlike diquarks within these baryons and hence, using the contact interaction, flavour-antitriplet scalar, pseudoscalar and vector, and flavour-sextet axial-vector quark-quark correlations can all play an active role. The model yields reasonable masses for all systems studied, and Faddeev amplitudes for ground states and associated parity partners that sketch a realistic picture of their internal structure: ground-state, even parity baryons are constituted, almost exclusively, from like-parity diquark correlations; but orbital angular momentum plays an important role in the rest-frame wave functions of odd-parity baryons, whose Faddeev amplitudes are dominated by odd-parity diquarks.
Comments:
11 pages, 4 figures, 4 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1705.03988 [pdf]
PRC(2017)·53 citations
02
[Submitted on 11 May 2017]
Iso-vector dipole resonance and shear viscosity in low energy heavy-ion collision
C. Q. Guo · Y. G. Ma · W. B. He · X. G. Cao · D. Q. Fang · X. G. Deng · C. L. Zhou
The ratio of shear viscosity over entropy density in low energy heavy-ion collision has been calculated by using the Green-Kubo method in the framework of an extended quantum molecular dynamics model. After the system almost reaching a local equilibration for a head-on $^{40}$ Ca+ $^{100}$ Mo collision, thermodynamic and transport properties are extracted. Meanwhile, iso-vector giant dipole resonance (IVGDR) of the collision system is also studied. By the Gaussian fits to the IVGDR photon spectra, the peak energies of IVGDR are extracted at different incident energies. The result shows that the IVGDR peak energy has a positive correlation with the ratio of shear viscosity over entropy density. This is a quantum effect and indicates a difference between nuclear matter and classical fluid.
Comments:
7 pages, 8 figures; Physical Review C (in press)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1705.04197 [pdf]
PRC(2017)·17 citations
03
[Submitted on 11 May 2017]
Investigation of giant dipole resonance in heavy deformed nuclei with the EQMD model
S. S. Wang · Y. G. Ma · X. G. Cao · W. B. He · H. Y. Kong · C. W. Ma
The deformation evolution of giant dipole resonance (GDR), in the chains of Sm and Nd isotopes, are investigated in the framework of an extended quantum molecular dynamics (EQMD) model. The mass number dependence of resonance peak position $(E_{m})$ in the major and minor axis directions of deformed nuclei as well as the difference $Δ E_{m}$ between them are described in detail. The correlation between the splitting ( $Δ E_{m} / E ˉ_{m}$ ) of the GDR spectra and the deformation( $β_{2}$ ) is further studied. The results confirm that $Δ E_{m} / E ˉ_{m}$ is proportional to $β_{2}$ . By comparing the calculation with the experimental data on photon absorption cross section $σ_{γ}$ , it shows that the EQMD model can quite well reproduce the shape of GDR spectra from spherical to prolate shape. The GDR shapes in $^{134}$ Sm, $^{136}$ Sm, $^{138}$ Sm, $^{130}$ Nd, $^{132}$ Nd and $^{134}$ Nd are also predicted. In addition, the symmetry energy coefficient $(E_{sy m})$ dependence of GDR spectra of $^{150}$ Nd is also discussed. It is found that the calculated GDR spectrum in the EQMD model is perfectly consistent with the experimental results when $E_{sy m}$ equals to 32 MeV.
Comments:
6 figures, 8 pages; Physical Review C (in press)
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1705.04203 [pdf]
PRC(2017)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Parity partners in the baryon resonance spectrum

Iso-vector dipole resonance and shear viscosity in low energy heavy-ion collision

Investigation of giant dipole resonance in heavy deformed nuclei with the EQMD model

Affiliations