Nuclear Theory·nucl-th

Monday·September 26, 2022

5 papers—2 primary·3 cross-listed

01
Effects of density-dependent spin-orbit interactions in Skyrme-Hartree-Fock-Bogoliubov calculations of the charge radii and densities of Pb isotopes
Yoshiko Kanada-En'yo
I have investigated the $N$ -dependence of the charge radii $r_{c}$ across $N = 126$ in the Pb isotopes and the surface densities of $^{208}$ Pb using new Skyrme interactions that contain a density-dependent spin-orbit term, which I have named the Skyrme-ddso interactions. I have compared the results obtained using Skyrme-Hartree-Fock-Bogoliubov calculations that employ the Skyrme-ddso interactions with the original Skyrme results and have discussed the effects of including the density-dependent spin-orbit term. The results for the kink behavior of $r_{c}$ at $N = 126$ in the Pb isotopes were improved by the inclusion of the density-dependent spin--orbit term. Moreover, the new Skyrme calculations yield better results for the inner part of the surface proton density of $^{208}$ Pb at $r \sim 5$ fm. The change in the $ℓ s$ potentials from the original Skyrme calculation contributes to the kink behavior through its effects on the $ℓ s$ splitting of the neutron $2 g_{7/2, 9/2}$ orbitals. It also affects the inner part of the surface proton density through its effect on the proton $1 h_{11/2}$ orbitals. I have further demonstrated that the change in the isoscalar-to-isovector ratio of the spin--orbit term makes only a minor contribution to the single-particle energies and to the kink behavior in the Pb isotopes. In addition, I have investigated $^{48}$ Ca using Skyrme-Hartree-Fock calculations with the new Skyrme interactions and have determined the effects of the density-dependent spin--orbit term on its radii and densities.
nucl-th2 citations
02
Stellar neutron capture reactions at low and high temperature
Thomas Rauscher
The determination of astrophysical reaction rates requires different approaches depending on the conditions in hydrostatic and explosive burning. The focus here is on astrophysical reaction rates for radiative neutron capture reactions. Relevant nucleosynthesis processes not only involve the s-process but also the i-, r- and $γ$ -processes, which from the nuclear perspective mainly differ in the relative interaction energies of neutrons and nuclei, and in the nuclear level densities of the involved nuclei. Emphasis is put on the difference between reactions at low and high temperature. Possible complications in the prediction and measurement of these reaction rates are illustrated and the connection between theory and experiment is addressed.
nucl-thastro-ph.HEastro-ph.SREPJA(2022)·7 citations
03
Resolving the Scales of the Quark-Gluon Plasma with Energy Correlators
Carlota Andres🇫🇷 · Fabio Dominguez🇪🇸 · Raghav Kunnawalkam Elayavalli🇺🇸 · Jack Holguin🇫🇷 · Cyrille Marquet🇫🇷 · Ian Moult🇺🇸
Jets provide us with ideal probes of the quark-gluon plasma (QGP) produced in heavy-ion collisions, since its dynamics at its different scales is imprinted into the multi-scale substructure of the final state jets. We present a new approach to jet substructure in heavy-ion collisions based on the study of correlation functions of energy flow operators. By analysing the two-point correlator of an in-medium quark jet, we demonstrate that the spectra of correlation functions robustly identify the scales defined by the properties of the QGP, particularly those associated with the onset of colour coherence.
↳ hep-phhep-exnucl-exnucl-thPRL(2023)·129 citations
04
Production of exotic electromagnetic bound systems in ultra-peripheral heavy ion collisions with two-photon processes
Gongming Yu🇨🇳 · Zhongxia Zhao · Yanbing Cai🇨🇳 · Quangui Gao🇨🇳 · Qiang Hu🇨🇳 · Haitao Yang
We calculate the production of exotic electromagnetic bound systems, which ia an consisting of a ( $l^{+} l^{-}$ ) bound state system such as positronium, dimuonium, and ditauonium, by photon-photon interaction with the equivalent photon approximation in ultra-peripheral heavy ion collisions considering the nuclear form factor. The numerical results demonstrate that the experimental study of positronium, dimuonium, and ditauonium in ultra-peripheral collisions is feasible at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies.
↳ hep-phnucl-th8 citations
05
Accreting neutron stars from the nuclear energy-density functional theory. II. Equation of state and global properties
A. F. Fantina🇫🇷 · J. L. Zdunik🇵🇱 · N. Chamel🇧🇪 · J. M. Pearson🇨🇦 · L. Suleiman🇵🇱 · S. Goriely🇧🇪
The accretion of matter onto the surface of a neutron star in a low-mass X-ray binary triggers X-ray bursts, whose ashes are buried and further processed thus altering the composition and the properties of the stellar crust. In this second paper of a series, the impact of accretion on the equation of state and on the global properties of neutron stars is studied in the framework of the nuclear energy-density functional theory. Considering ashes made of $^{56}$ Fe, we calculated the equations of state using the same Brussels-Montreal nuclear energy-density functionals BSk19, BSk20, and BSk21, as those already employed for determining the crustal heating in our previous study for the same ashes. All regions of accreting neutron stars were treated in a unified and thermodynamically consistent way. With these equations of state, we determined the mass, radius, moment of inertia, and tidal deformability of accreted neutron stars and compared with catalyzed neutron stars for which unified equations of state based on the same functionals are available. The equation of state of accreted neutron stars is found to be significantly stiffer than that of catalyzed matter, with an adiabatic index $Γ \approx 4/3$ throughout the crust. For this reason, accreting neutron stars have larger radii. However, their crustal moment of inertia and their tidal deformability are hardly changed provided density discontinuities at the interface between adjacent crustal layers are properly taken into account. The enhancement of the stiffness of the equation of state of accreting neutron stars is mainly a consequence of nuclear shell effects, thus confirming the importance of a quantum treatment as stressed in our first study. With our previous calculations of crustal heating using the same functionals, we have thus obtained consistent microscopic inputs for simulations of accreting neutron stars.
↳ astro-ph.HEnucl-thAstron.Astrophys.(2022)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE

Effects of density-dependent spin-orbit interactions in Skyrme-Hartree-Fock-Bogoliubov calculations of the charge radii and densities of Pb isotopes

Stellar neutron capture reactions at low and high temperature

Resolving the Scales of the Quark-Gluon Plasma with Energy Correlators

Production of exotic electromagnetic bound systems in ultra-peripheral heavy ion collisions with two-photon processes

Accreting neutron stars from the nuclear energy-density functional theory. II. Equation of state and global properties

Affiliations