Nuclear Theory·nucl-th

Wednesday·August 2, 2023

14 papers—8 primary·6 cross-listed

01
Effects of Phi and $σ^{*}$ -meson on properties of hyperon stars including $Δ$ resonance
Chen Wu🇨🇳 · Wenjun Guo🇨🇳
In this work, we study the properties of neutron stars using the linear Relativistic Mean-Field (RMF) theory and consider multiple degrees of freedom inside neutron stars, including hyperons and $Δ$ resonances. We investigate different coupling parameters $x_{σ Δ}$ between $Δ$ resonances and nucleons and compare the differences between neutron stars with and without strange mesons $σ^{*}$ and $ϕ$ . These effects include particle number distributions, equations of state (EOS), mass-radius relations, and tidal deformabilities. To overcome the "hyperon puzzle," we employ the $σ - c u t$ scheme to obtain neutron stars with masses up to $2 M_{⊙}$ . We find that strange mesons appear at around 3 $ρ_{0}$ and reduce the critical density of baryons in the high-density region. With increasing coupling parameter $x_{σ Δ}$ , the $Δ$ resonances suppress hyperons, leading to a shift of the critical density towards lower values. The early appearance of $Δ$ resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while $Δ$ resonances predominantly soften the EOS in the low-density region. By calculating tidal deformabilities and comparing with astronomical observation GW170817, we find that the inclusion of $Δ$ resonances decreases the radius of neutron stars.
nucl-thastro-ph.HEEur.Phys.J.Plus(2025)·3 citations
02
Dynamical induced quark spin polarization by magnetic field at the early stage of heavy-ion collisions
Anping Huang🇨🇳 · Zilin Yuan🇨🇳 · Mei Huang🇨🇳
We present a comprehensive analysis of the dynamic process of quark spin polarization induced by magnetic fields at the pre-thermal stage in heavy-ion collisions by using the recently developed theoretical tool of chiral kinetic theory. Our findings demonstrate that the spin polarization of quarks is highly sensitive to the interactions between quarks. These interactions can delay the decay of early spin polarization vector while accelerating the decay of later spin polarization vector. Specifically, our simulations show the detailed process of how magnetic fields polarize quarks within the fireball and reveal that quark interactions lead to an acceleration effect on the average spin. Notably, the fireball of quark-gluon plasma (QGP) in its early stages exhibits an incomplete electromagnetic response effect, which differs from the response predicted by Lenz's law. This discrepancy arises from quantum corrections involving the interactions between quark spin and electromagnetic fields.
nucl-thhep-phPRD(2024)·1 citation
03
Study of multinucleon transfer mechanism in $^{160} Gd +^{186} W$ collisions in stochastic mean-field theory}
S. Ayik · M. Arik · E. Erbayri · O. Yilmaz · A. S. Umar
Multinucleon transfer mechanism in collision of $^{160} Gd +^{186} W$ system is investigated in the framework of quantal transport description, based on the stochastic mean-field (SMF) theory. The SMF theory provides a microscopic approach for nuclear dynamics beyond the time-dependent Hartree-Fock (TDHF) approach by including mean-field fluctuations. Cross-sections for the primary fragment production are determined in the quantal transport description and compared with the available data.
nucl-th0 citations
04
Magnetic dipole operator from chiral effective field theory for many-body expansion methods
R. Seutin🇩🇪 · O. J. Hernandez🇩🇪 · T. Miyagi🇩🇪 · S. Bacca🇩🇪 · K. Hebeler🇩🇪 · S. König🇩🇪 · A. Schwenk🇩🇪
Many-body approaches for atomic nuclei generally rely on a basis expansion of the nuclear states, interactions, and current operators. In this work, we derive the representation of the magnetic dipole operator in plane-wave and harmonic-oscillator basis states, as needed for Faddeev calculations of few-body systems or many-body calculations within, e.g., the no-core shell model, the in-medium renormalization group, coupled-cluster theory, or the nuclear shell model. We focus in particular on the next-to-leading-order two-body contributions derived from chiral effective field theory. We provide detailed benchmarks and also comparisons with quantum Monte Carlo results for three-body systems. The derived operator matrix elements represent the basic input for studying magnetic properties of atomic nuclei based on chiral effective field theory.
nucl-thnucl-exPRC(2023)·13 citations
05
Correlations between charge radii differences of mirror nuclei and stellar observables
P. Bano · S. P. Pattnaik · M. Centelles · X. Viñas · T. R. Routray
The correlation between the charge radii differences in mirror nuclei pairs and the neutron skin thickness has been studied with the so-called finite range simple effective interaction over a wide mass region. The so far precisely measured charge radii difference data within their experimental uncertainty ranges in the 34Ar-34S, 36Ca-36S, 38Ca-38Ar, and 54Ni-54Fe mirror pairs are used to ascertain an upper limit for the slope parameter of the nuclear symmetry energy L $\approx$ 100 MeV. This limiting value of L is found to be consistent with the upper bound of the NICER PSR J0740+6620 constraint at 1 $σ$ level for the radius R $_{1.4}$ of 1.4 M $_{⊙}$ neutron stars. The lower bound of the NICER R $_{1.4}$ data constrains the lower limit of L to $\approx$ 70 MeV. Within the range for L = 70-100 MeV the tidal deformability $Λ^{1.4}$ constraint, which is extracted from the GW170817 event at 2 $σ$ level, and the recent PREX-2 and CREX data on the neutron skin thickness are discussed.
nucl-thastro-ph.SRnucl-exPRC(2023)·31 citations
06
Orbital-free Density Functional Theory: differences and similarities between electronic and nuclear systems
Gianluca Colo' · Kouichi Hagino
Orbital-free Density Functional Theory (OF-DFT) has been used when studying atoms, molecules and solids. In nuclear physics, there has been basically no application of OF-DFT so far, as the Density Functional Theory (DFT) has been widely applied to the study of many nuclear properties mostly within the Kohn-Sham (KS) scheme. There are many realizations of nuclear KS-DFT, but computations become very demanding for heavy systems, such as superheavy nuclei and the inner crust of neutron stars, and it is hard to describe exotic nuclear shapes using a finite basis made with a limited number of orbitals. These bottlenecks could, in principle, be overcome by an orbital-free formulation of DFT. This work is a first step towards the application of OF-DFT to nuclei. In particular, we have implemented possible choices for an orbital-free kinetic energy and solved the associated Schrödinger equation either with simple potentials or with simplified nuclear density functionals. While the former choice sheds light on the differences between electronic and nuclear systems, the latter choice allows us discussing the practical applications to nuclei and the open questions.
nucl-thcond-mat.otherPTEP(2023)·6 citations
07
"Onishi" formulas
K. Neergård
The term "Onishi" formula refers to a family of related formulas for the overlap amplitude of two Bogolyubov quasi-fermion vacua. As a common feature, these formulas display a square root, which gives rise to an apparent sign ambiguity. For some members of the family, this sign ambiguity is real and unavoidable while in some other cases it is not. The relation between the different Onishi formulas is discussed.
nucl-thNucl.Theor.(2023)·1 citation
08
Two-pion interferometry for partially coherent sources in relativistic heavy-ion collisions in a multi-phase transport model
Shi-Yao Wang🇨🇳 · Jun-Ting Ye🇨🇳 · Wei-Ning Zhang🇨🇳
We perform two-pion Hanbury Brown-Twiss (HBT) interferometry for the partially coherent pion-emitting sources in relativistic heavy-ion collisions, using a multi-phase transport (AMPT) model. A longitudinal coherent emission length, as well as a transverse coherent emission length, are introduced to the pion generation coordinates in calculating the HBT correlation functions of the partially coherent sources. We compare the model results with and without coherent emission conditions with experimental data in Au-Au collisions at center-of-mass energy $s_{N N} =$ 200 GeV, and in Pb-Pb collisions at center-of-mass energy $s_{N N} =$ 2.76 TeV, and find that the HBT results of the partially coherent sources are closer to the experimental data than those of chaotic sources.
nucl-thPRC(2024)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE