Nuclear Theory·nucl-th

Friday·December 22, 2023

17 papers—9 primary·8 cross-listed

01
[Submitted on 20 Dec 2023]
Impact of tensor interactions and scalar mixing on covariant energy density functionals
Marc Salinas · Jorge Piekarewicz
The recent pioneering campaigns conducted by the Lead Radius Experiment (PREX) and the Calcium Radius Experiment (CREX) collaborations have uncovered major deficiencies in the theoretical description of some fundamental properties of atomic nuclei. Following a recent refinement to the isovector sector of covariant energy density functionals [1], we present here additional improvements to the functional by including both tensor couplings and an isoscalar-isovector mixing term in the scalar sector. Motivated by the distinct surface properties of calcium and lead, we expect that the tensor terms that generate derivative couplings will help break the linear correlation between the neutron skin thickness of these two nuclei. Moreover, the addition of these new terms mitigates most of the problems identified in Ref.[1] in describing the properties of both finite nuclei and neutron stars. While significant progress has been made in reconciling the PREX-CREX results without compromising other observables, the final resolution awaits the completion of a proper calibration for this new class of functionals. We expect that powerful reduced basis methods used recently to create efficient emulators will be essential to accomplish this task.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.13474 [pdf]
PRC(2024)·18 citations
02
[Submitted on 21 Dec 2023]
Relativistic heat conduction in the large-flux regime
Lorenzo Gavassino
We propose a general procedure for evaluating, directly from microphysics, the constitutive relations of heat-conducting fluids in regimes of large fluxes of heat. Our choice of hydrodynamic formalism is Carter's two-fluid theory, which happens to coincide with Öttinger's GENERIC theory for relativistic heat conduction. This is a natural framework, as it should correctly describe the relativistic ``inertia of heat'' as well as the subtle interplay between reversible and irreversible couplings. We provide two concrete applications of our procedure, where the constitutive relations are evaluated respectively from maximum entropy hydrodynamics and Chapman-Enskog theory.
Comments:
9 pages, 2 figures, published on Entropy, see https://www.mdpi.com/1099-4300/26/2/147
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
arXiv:
2312.13553 [pdf]
Entropy(2024)·2 citations
03
[Submitted on 21 Dec 2023]
Probing configuration of $α$ clusters with spectator particles in relativistic heavy-ion collisions
Lu-Meng Liu🇨🇳 · Song-Jie Li🇨🇳 · Zhen Wang🇨🇳 · Jun Xu🇨🇳 · Zhong-Zhou Ren🇨🇳 · Xu-Guang Huang🇨🇳
We propose to use spectator particle yield ratios to probe the configuration of $α$ clusters in $^{12}$ C and $^{16}$ O by their collisions at RHIC and LHC energies. The idea is illustrated based on initial density distributions with various $α$ -cluster configurations generated by a microscopic cluster model, and without $α$ clusters from mean-field calculations. The multifragmentation of the spectator matter produces more spectator light nuclei including $α$ clusters in collisions of nuclei with chain structure of $α$ clusters, compared to those of nuclei with a more compact structure. The yield ratio of free spectator neutrons to spectator particles with mass-to-charge ratio $A / Z = 2$ scaled by their masses can be practically measured by the zero-degree calorimeter (ZDC) at RHIC and LHC, serving as a clean probe free from modeling the complicated dynamics at midrapidities.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
arXiv:
2312.13572 [pdf]
PLB(2024)·16 citations
04
[Submitted on 21 Dec 2023]
Microscopic study of $M$ 1 resonances in Sn isotopes
Shuai Sun · Li-Gang Cao · Feng-Shou Zhang · Hiroyuki Sagawa · Gianluca Colò
The magnetic dipole ( $M$ 1) resonances of even-even $^{112 - 120, 124}$ Sn isotopes are investigated in the framework of the self-consistent Skyrme Hartree-Fock (HF) + BCS and Quasiparticle Random Phase Approximation (QRPA). The Skyrme energy density functionals SLy5 and T11 with and without tensor terms are adopted in our calculations. The mixed type pairing interaction is used to take care of the pairing effect for open-shell nuclei both in the ground and excited states calculations. The calculated magnetic dipole strengths are compared with available experimental data. The QRPA results calculated by SLy5 and T11 with tensor force show a better agreement with the experimental data than those without the tensor force. By analyzing the HF and QRPA strength distributions of $^{112}$ Sn and $^{124}$ Sn, we discuss the effect of tensor force on the $M$ 1 resonances in detail. It is found that the $M$ 1 resonance is sensitive to the tensor interaction, and favors especially a negative triplet-odd tensor one. Depending on the nucleus, a quenching factor of the $M$ 1 operator of about 0.71-0.95 is needed to reproduce the total observed transition strength. In our calculations, we also find some low-lying, pygmy-type magnetic dipole states distributed below 6.0 MeV, and they are formed mainly from the neutron configuration $ν$ 2 $d_{5/2}$ $\to$ $ν$ 2 $d_{3/2}$ .
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.13624 [pdf]
PRC(2024)·3 citations
05
[Submitted on 21 Dec 2023]
Deuteron production in a combined thermal and coalescence framework for heavy-ion collisions in the few-GeV energy regime
Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱 · Piotr Salabura🇵🇱 · Nikodem Witkowski🇵🇱
A recently formulated thermal model for hadron production in heavy-ion collisions in the few-GeV energy regime is combined with the idea that some part of protons and neutrons present in the original thermal system forms deuterons via the coalescence mechanism. Using realistic parametrizations of the freeze-out conditions, which reproduce well the spectra of protons and pions, we make predictions for deuteron transverse-momentum and rapidity spectra. The best agreement with the experimentally known deuteron yield is obtained if the freeze-out temperature is relatively high and, accordingly, the system size at freeze-out is rather small. In addition, the standard Gaussian distribution of the relative distance between nucleons is replaced by the distribution resulting from their independent and approximately uniform production inside the initial thermal system.
Comments:
23 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2312.13824 [pdf]
Acta Phys.Polon.B(2024)·5 citations
06
[Submitted on 21 Dec 2023]
Effect of the equation of state for dilute neutron matter on the composition of the inner crust of neutron stars
Sunny Kumar Gupta🇮🇳 · Michael Urban🇫🇷
The composition of the inner crust of neutron stars is usually studied using phenomenological interactions such as Skyrme energy-density functionals. But most of these functionals do not agree well with ab-initio calculations of very dilute neutron matter. In this work, we study the inner crust of neutron stars in the model of phase coexistence of dense neutron-rich nuclear clusters and dilute neutron gas, and we investigate how employing a realistic microscopic equation of state to the neutron gas alters the composition. Our results indicate that with a functional that reproduces the correct equation of state of neutron matter at moderate densities, one can obtain a good description of the crust even if the functional does not have the correct behavior at extremely low density.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.13836 [pdf]
PRC(2024)·3 citations
07
[Submitted on 21 Dec 2023]
Towards consistent nuclear interactions from chiral Lagrangians II: Symmetry preserving regularization
Hermann Krebs🇩🇪 · Evgeny Epelbaum🇩🇪
Low-energy nuclear structure and reactions can be described in a systematically improvable way using the framework of chiral effective field theory. This requires solving the quantum mechanical many-body problem with regularized nuclear forces and current operators, derived from the most general effective chiral Lagrangian. To maintain the chiral and gauge symmetries, a symmetry preserving cutoff regularization has to be employed when deriving nuclear potentials. Here, we discuss various regularization techniques and show how this task can be accomplished by regularizing the pion field in the effective chiral Lagrangian using the gradient flow method. The actual derivation of the nuclear forces and currents from the regularized effective Lagrangian can be carried out utilizing the novel path-integral approach introduced in our earlier paper.
Comments:
19 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2312.13932 [pdf]
PRC(2024)·27 citations
08
[Submitted on 21 Dec 2023]
Event-by-event Kinetic Description of Pre-Equilibrium Charge Evolution in QCD Plasma
Travis Dore🇩🇪 · Xiaojian Du🇩🇪 · Sören Schlichting🇩🇪
We use QCD effective kinetic theory to calculate far-from-equilibrium dynamics on an event-by-event basis within the Kø{}MPø{}ST framework. We present non-equilibrium charge response functions and the dynamical evolution of the conserved charge current pertinent to the early-time dynamics of heavy-ion collisions at the highest energies. The Kø{}MPø{}ST framework with conserved baryon, strangeness, and electric charges can then be readily implemented into a multistage model allowing for the initialization of a non-equilibrium charge current in hydrodynamic simulations.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.14081 [pdf]
EPJ Web Conf.(2024)·3 citations
09
[Submitted on 21 Dec 2023]
Equation of state at neutron-star densities and beyond from perturbative QCD
Oleg Komoltsev🇳🇴 · Rahul Somasundaram🇺🇸 · Tyler Gorda🇩🇪 · Aleksi Kurkela🇳🇴 · Jérôme Margueron🇫🇷 · Ingo Tews🇺🇸
We explore the consequences of imposing robust thermodynamic constraints arising from perturbative Quantum Chromodynamics (QCD) when inferring the dense-matter equation-of-state (EOS). We find that the termination density, up to which the EOS modeling is performed in an inference setup, strongly affects the constraining power of the QCD input. This sensitivity in the constraining power arises from EOSs that have a specific form, with drastic softening immediately above the termination density followed by a strong stiffening. We also perform explicit modeling of the EOS down from perturbative-QCD densities to construct a new QCD likelihood function that incorporates additional perturbative-QCD calculations of the sound speed and is insensitive to the termination density, which we make publicly available.
Comments:
16 pages, 11 figures. Version 2: added Appendix A, corrected minor error in the marginalization code that introduced small noise in results; updated figures accordingly. The link to the publicly available Marginalized QCD likelihood function https://doi.org/10.5281/zenodo.10592568
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.14127 [pdf]
PRD(2024)·71 citations

Affiliations

first authorsco-authorsvia INSPIRE