Nuclear Theory·nucl-th

Tuesday·November 28, 2023

20 papers—7 primary·13 cross-listed

01
Uniform descriptions of pseudospin symmetries in bound and resonant states
Ting-Ting Sun · Zhi Pan Li
As a continuation of our previous work on the conservation and breaking of the pseudospin symmetry (PSS) in resonant states [Phys. Lett. B 847, 138320 (2023)}], in this work, the PSS in nuclear single-particle bound and resonant states are investigated uniformly within a relativistic framework by exploring the poles of the Green's function in spherical Woods-Saxon potentials. As the potential depths increase from zero to finite depths, the PS partners evolve from resonant states to bound states. In this progress,the PSS is broken gradually with energy, width, and density splittings. Specially, the energy and width splittings for the resonant and bound states are directly determined by the ratio of the pseudo spin-orbit potentials between the PS partners. Obvious threshold effect is observed for the energy splitting at a critical potential depth, with which the PS partners locate between the centrifugal barriers of PS partners. The differences in the density distributions of the lower component between the PS partners are manifested in the phase shift for the resonant states and amplitudes for bound states. Besides, the evolution of the phase shift as the potential depth is consistent with those for the width splitting.
nucl-thPLB(2024)·5 citations
02
Improved determination of the oscillator parameters in nuclei
Latsamy Xayavong · Yeunhwan Lim
The oscillator parameter in nuclei is refitted to reproduce the available charge radius data. As an important improvement, we include the Coulomb term evaluated within the assumption of a uniformly charged sphere, and take into account the symmetry effect induced by the difference between N and Z numbers in a straightforward manner using the conventional parameterization. The Coulomb interaction has repulsive effect, causing the wave functions to extend further toward the nucleus exterior, resulting in an effectively larger oscillator length parameter. The symmetry effect is attractive for protons in neutron-rich nuclei and for neutrons in proton-rich nuclei, and repulsive for the other cases. Therefore, three distinct oscillator parameters are determined: one for protons, one for neutrons, and one isospin-invariant version, which is obtained by subtracting the Coulomb and symmetry contributions. Additionally, we explore the direct fit of the harmonic oscillator wave functions to the eigenfunctions of the Hartree-Fock mean field using the Skyrme interaction. Generally, this method agrees well with the others for light nuclei, typically up to $^{40}$ Ca. Beyond this nucleus, however, the results begin to diverge over the orbits chosen for the fit. Only the parameters values obtained for the last occupied states agree remarkably well with the conventional ones throughout the mass range under consideration.
nucl-thnucl-ex0 citations
03
ANCs of the bound states of $^{16}$ O deduced from elastic $α$ - $^{12}$ C scattering data
Shung-Ichi Ando (Sunmoon Univ.)
Asymptotic normalization coefficients (ANCs) of the $0_{1}^{+}$ , $0_{2}^{+}$ , $1_{1}^{-}$ , $2_{1}^{+}$ , $3_{1}^{-}$ ( $l_{i t h}^{π}$ ) bound states of $^{16}$ O are deduced from the phase shift data of elastic $α$ - $^{12}$ C scattering at low energies. $S$ matrices of elastic $α$ - $^{12}$ C scattering are constructed within cluster effective field theory (EFT), in which both bound and resonant states of $^{16}$ O are considered. Parameters in the $S$ matrices are fitted to the precise phase shift data below the $p$ - $^{15}$ N breakup energy for the partial waves of $l = 0, 1, 2, 3, 4, 5, 6$ , and the ANCs are calculated by using the wave function normalization factors of $^{16}$ O propagators for $l = 0, 1, 2, 3$ . We review the values of ANCs, which are compared with other results in the literature, and discuss uncertainties of the ANCs obtained from the elastic $α$ - $^{12}$ C scattering data in cluster EFT.
nucl-thnucl-exFew Body Syst.(2024)·4 citations
04
Theories of Relativistic Dissipative Fluid Dynamics
Gabriel S. Rocha🇺🇸 · David Wagner🇩🇪 · Gabriel S. Denicol🇧🇷 · Jorge Noronha🇺🇸 · Dirk H. Rischke🇩🇪
Relativistic dissipative fluid dynamics finds widespread applications in high-energy nuclear physics and astrophysics. However, formulating a causal and stable theory of relativistic dissipative fluid dynamics is far from trivial; efforts to accomplish this reach back more than 50 years. In this review, we give an overview of the field and attempt a comparative assessment of (at least most of) the theories for relativistic dissipative fluid dynamics proposed until today and used in applications.
nucl-thhep-phhep-thphysics.flu-dynEntropy(2024)·77 citations
05
Corrections to Landau Fermi-liquid fixed-point approximation in nonlinear bosonized theory: Application to $g_{A}^{L}$ in nuclei
Long-Qi Shao🇨🇳 · Mannque Rho🇫🇷
We calculated in nonlinear bosonized theory $1/ N ˉ$ corrections to the Landau Fermi-liquid fixed-point (FLFP) axial-vector coupling constant in nuclear matter $g_{A}^{L} \approx 1$ to which the Landau parameter $F_{1}^{ω}$ predominantly contributes. We obtain the correction to $F_{1}^{ω}$ to calculate the correction $δ g_{A}^{L}$ to the axial-vector coupling constant $g_{A}^{L}$ at the nuclear saturation density. It comes out to be extremely small, $δ g_{A}^{L} \sim O (1 0^{- 4})$ . We discuss how the "dilaton-limit fixed-point (DLFP)" result $g_{A} = 1$ can be preserved from finite nuclei to high densities relevant to massive neutron stars and its possible impact on $0 ν β β$ decay processes involved in going beyond the Standard Model.
nucl-thhep-phPRC(2024)·6 citations
06
Multireference covariant density-functional theory for the low-lying states of odd-mass nuclei
E. F. Zhou · X. Y. Wu · J. M. Yao
We extend multireference covariant density-functional theory (MR-CDFT) based on a relativistic point-coupling energy functional to describe the low-lying states of odd-mass nuclei. The nuclear wave function is constructed as a superposition of quadrupole-octupole deformed mean-field configurations, with projection onto angular momentum, particle numbers, and parity within the framework of the generator coordinate method. Using $^{25}$ Mg as an example, we calculate the energy spectrum, electric multipole, and magnetic dipole transition strengths based on three different schemes for the mean-field configurations of odd-mass nuclei. We find that the low-energy structure of $^{25}$ Mg is reasonably reproduced in all three schemes. In particular, the effect of octupole correlation is illustrated in the application to the low-lying parity doublets of $^{21}$ Ne. This work demonstrates the success of the MR-CDFT for the low-lying states of odd-mass nuclei with possible strong quadruple-octupole correlations.
nucl-thPRC(2024)·17 citations
07
Effects of hyperon potentials and symmetry energy in quark deconfinement
Rajesh Kumar🇺🇸 · Krishna Aryal🇺🇸 · Alexander Clevinger🇺🇸 · Veronica Dexheimer🇺🇸
In this letter we discuss how the results of recent nuclear experiments that correspond to measurements at low densities can affect the equation of state at large densities and temperatures, changing the particle composition and ultimately influencing deconfinement to quark matter. In particular, saturation values of the hyperon potentials affect the hyperon content, while the symmetry energy at saturation directly regulates how the stiffness of the equation of state changes with isospin. We make use of a chiral model that describes nucleons, hyperons, and quarks to show how astrophysical conditions, such as the ones in neutron stars, present the ideal ground to study the effects of these two quantities in dense matter. In this case, for small charge fraction/ large isospin asymmetry, the couplings that reproduce different symmetry energy slopes can significantly modify deconfinement, with quantitative changes in the critical chemical potential depending on the deconfining potential. On the other hand, different values of the parameter that controls the hyperon potentials (kept within a range close to experimental data) do not affect deconfinement significantly.
nucl-thastro-ph.HEastro-ph.SRPLB(2024)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE

Uniform descriptions of pseudospin symmetries in bound and resonant states

Improved determination of the oscillator parameters in nuclei

ANCs of the bound states of 16O deduced from elastic α-12C scattering data

Theories of Relativistic Dissipative Fluid Dynamics

Corrections to Landau Fermi-liquid fixed-point approximation in nonlinear bosonized theory: Application to gAL​ in nuclei

Multireference covariant density-functional theory for the low-lying states of odd-mass nuclei

Effects of hyperon potentials and symmetry energy in quark deconfinement

Affiliations

ANCs of the bound states of $^{16}$ O deduced from elastic $α$ - $^{12}$ C scattering data

Corrections to Landau Fermi-liquid fixed-point approximation in nonlinear bosonized theory: Application to $g_{A}^{L}$ in nuclei