Nuclear Theory·nucl-th

Thursday·September 8, 2022

11 papers—5 primary·6 cross-listed

01
[Submitted on 6 Sept 2022]
Comparative study on charge radii and their kinks at magic numbers
Tomoya Naito · Tomohiro Oishi · Hiroyuki Sagawa · Zhiheng Wang
Isotope dependences of charge radii, i.e., isotope shifts, calculated by the Skyrme Hartree-Fock, the relativistic mean-field, and the relativistic Hartree-Fock calculations are compared against the experimental data of magic and semimagic nuclei. It is found that the tensor interaction plays a role in reproducing the ``kink'' behavior, irregularity of isotope shifts at the neutron magic number, in the relativistic Hartree-Fock approach. With several Skyrme models, it is found that the kink behavior can be reproduced with the spin-orbit interaction having nonzero isovector channel. The single-particle orbitals near the Fermi energy are crucial to determine the kink size. The effects of the symmetry energy and the pairing interaction are also discussed in relation to the kink behavior.
Comments:
22 pages, 34 figures, 10 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2209.02857 [pdf]
PRC(2023)·35 citations
02
[Submitted on 6 Sept 2022]
Massive neutron stars with small radii in relativistic mean-field models optimized to nuclear ground states
Tsuyoshi Miyatsu🇰🇷 · Myung-Ki Cheoun🇰🇷 · Kyungsik Kim🇰🇷 · Koichi Saito🇯🇵
We present an equation of state (EoS) for neutron stars using the relativistic mean-field model with isoscalar- and isovector-meson mixing. Taking into account the results of the neutron skin thickness, $R_{skin}$ , of $^{208}$ Pb reported by the PREX collaboration, the dimensionless tidal deformability of a canonical neutron star observed from GW170817, and a $2.6$ $M_{⊙}$ compact star implied by the secondary component of GW190814, a new effective interaction is constructed so as to reproduce the saturation condition of nuclear matter and the ground-state properties of finite, closed-shell nuclei. We find that the neutron star EoS exhibits the rapid stiffening around twice the nuclear saturation density, which is caused by the soft nuclear symmetry energy, $E_{sym}$ . It is also noticeable that the thick $R_{skin}$ from the PREX-2 experiment can be achieved with the small slope parameter of $E_{sym}$ stemming from the isoscalar-meson mixing. Thus, we speculate that the secondary component of GW190814 is the heaviest neutron star ever discovered.
Comments:
8 pages, 5 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2209.02861 [pdf]
4 citations
03
[Submitted on 7 Sept 2022]
Strange mesons in nuclei and neutron stars
Laura Tolos🇪🇸
The present status in the field of strange mesons in nuclei and neutron stars is reviewed. In particular, the $K ˉ N$ interaction, that is governed by the presence of the $Λ (1405)$ , is analyzed and the formation of the $K ˉ N N$ bound state is discussed. Moreover, the properties of $K ˉ$ in dense nuclear matter are studied, in connection with strangeness production in nuclear collisions and kaon condensation in neutron stars.
Comments:
6 pages, 1 figure, 1 table, contribution to the proceedings of the 14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022), Prague (Czech Republic), June 27-July 1, 2022
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2209.03103 [pdf]
EPJ Web Conf.(2022)·0 citations
04
[Submitted on 7 Sept 2022]
Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin
Lu-Meng Liu🇨🇳 · Chun-Jian Zhang🇺🇸 · Jun Xu🇨🇳 · Jiangyong Jia🇺🇸 · Guang-Xiong Peng🇨🇳
Besides the yield ratio of free spectator neutrons produced in ultracentral $^{96}$ Zr+ $^{96}$ Zr to $^{96}$ Ru+ $^{96}$ Ru collisions, we propose that the yield ratio $N_{n} / N_{p}$ of free spectator neutrons to protons in a single collision system at RHIC and LHC can be a more sensitive probe of the neutron-skin thickness $Δ r_{np}$ and the slope parameter $L$ of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions of colliding nuclei obtained from Skyrme-Hartree-Fock-Bogolyubov calculations, and a Glauber model that provides information of spectator matter. The final spectator particles are produced from direct emission, clusterization by a minimum spanning tree algorithm or a Wigner function approach, and deexcitation of heavy clusters by GEMINI. A larger $Δ r_{np}$ associated with a larger $L$ value increases the isospin asymmetry of spectator matter and thus leads to a larger $N_{n} / N_{p}$ , especially in ultracentral collisions where the multiplicity of free nucleons are free from the uncertainties of cluster formation and deexcitation. We have further shown that the double ratio of $N_{n} / N_{p}$ in isobaric collision systems or in collisions by isotopes helps to cancel the detecting efficiency for protons. Effects from nuclear deformation and electromagnetic excitation are studied, and they are found to be subdominant compared to the expected sensitivity to $Δ r_{np}$ .
Comments:
16 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
arXiv:
2209.03106 [pdf]
PRC(2022)·26 citations
05
[Submitted on 7 Sept 2022]
Low-energy nuclear physics and global neutron star properties
Brett V. Carlson🇧🇷 · Mariana Dutra🇧🇷 · Odilon Lourenço🇧🇷 · Jérôme Margueron🇫🇷
We address the question of the role of low-energy nuclear physics data in constraining neutron star global properties, e.g., masses, radii, angular momentum, and tidal deformability, in the absence of a phase transition in dense matter. To do so, we assess the capacity of 415 relativistic mean field and non-relativistic Skyrme-type interactions to reproduce the ground state binding energies, the charge radii and the giant monopole resonances of a set of spherical nuclei. The interactions are classified according to their ability to describe these characteristics and we show that a tight correlation between the symmetry energy and its slope is obtained providing $N = Z$ and $N \neq = Z$ nuclei are described with the same accuracy (mainly driven by the charge radius data). By additionally imposing the constraints from isobaric analog states and neutron skin radius in $^{208}$ Pb, we obtain the following estimates: $E_{sy m, 2} = 31.8 \pm 0.7$ MeV and $L_{sy m, 2} = 58.1 \pm 9.0$ MeV. We then analyze predictions of neutron star properties and we find that the 1.4 $M_{⊙}$ neutron star (NS) radius lies between 12 and 14 km for the "better" nuclear interactions. We show that i) the better reproduction of low-energy nuclear physics data by the nuclear models only weakly impacts the global properties of canonical mass neutron stars and ii) the experimental constraint on the symmetry energy is the most effective one for reducing the uncertainties in NS matter. However, since the density region where constraints are required are well above densities in finite nuclei, the largest uncertainty originates from the density dependence of the EDF, which remains largely unknown.
Comments:
26 pages, 20 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2209.03257 [pdf]
PRC(2023)·38 citations
06
[Submitted on 6 Sept 2022] (cross-list from astro-ph.HE)
Deducing Neutron Star Equation of State Parameters Directly From Telescope Spectra with Uncertainty-Aware Machine Learning
Delaney Farrell🇺🇸 · Pierre Baldi🇺🇸 · Jordan Ott🇺🇸 · Aishik Ghosh🇺🇸 · Andrew W. Steiner🇺🇸 · Atharva Kavitkar🇩🇪 · Lee Lindblom🇺🇸 · Daniel Whiteson🇺🇸 · Fridolin Weber🇺🇸
Neutron stars provide a unique laboratory for studying matter at extreme pressures and densities. While there is no direct way to explore their interior structure, X-rays emitted from these stars can indirectly provide clues to the equation of state (EOS) of superdense nuclear matter through the inference of the star's mass and radius. However, inference of EOS directly from a star's X-ray spectra is extremely challenging and is complicated by systematic uncertainties. The current state of the art is to use simulation-based likelihoods in a piece-wise method, which first infer the star's mass and radius to reduce the dimensionality of the problem, and from those quantities infer the EOS. We demonstrate a series of enhancements to the state of the art, in terms of realistic uncertainty quantification and improved regression of physical properties with machine learning. We also demonstrate novel inference of the EOS directly from the high-dimensional spectra of observed stars, avoiding the intermediate mass-radius step. Our network is conditioned on the sources of uncertainty of each star, allowing for natural and complete propagation of uncertainties to the EOS.
Comments:
24 pages, 20 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2209.02817 [pdf]
JCAP(2023)·19 citations
07
[Submitted on 6 Sept 2022] (cross-list from hep-th)
Denominator Regularization in Quantum Field Theory
W. A. Horowitz🇿🇦
We propose a novel regularization scheme in quantum field theory, denominator regularization (den reg). As simple to apply as dimensional regularization, and similarly compatible with a minimal subtraction renormalization scheme, den reg manifestly 1) maintains Lorentz invariance, 2) maintains gauge invariance, 3) maintains supersymmetry, 4) correctly predicts the axial anomaly, and 5) yields Green functions that satisfy the Callan-Symanzik equation. Den reg also naturally enables regularization in asymmetric spacetimes, finite spacetimes, curved spacetimes, and in thermal field theory.
Comments:
6 pages
Subjects:
High Energy Physics — Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.02820 [pdf]
8 citations
08
[Submitted on 7 Sept 2022] (cross-list from hep-ph)
Tetraquark mixing supported by the partial decay widths of two light-meson nonets
Hungchong Kim🇰🇷 · K. S. Kim🇰🇷
Recently, the tetraquark mixing framework has been proposed as a possible structure for the two light-meson nonets in the $J^{P} = 0^{+}$ channel, the light nonet composed of $a_{0} (980)$ , $K_{0}^{*} (700)$ , $f_{0} (500)$ , $f_{0} (980)$ , and the heavy nonet of $a_{0} (1450)$ , $K_{0}^{*} (1430)$ , $f_{0} (1370)$ , $f_{0} (1500)$ . Among various signatures, we report in this work that their partial decay widths collected from various experimental data in Particle Data Group (PDG) can support this mixing scheme also. In particular, we demonstrate that the couplings of the light nonet to two pseudoscalar mesons estimated from the partial widths are consistently stronger than those of the heavy nonet. This consistent feature agrees qualitatively well with the predictions from the tetraquark mixing framework and, therefore, provides supporting evidence for the tetraquark mixing.
Comments:
Substantially revised. 9 pages, no figures. Accepted for publication in EPJC
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2209.02958 [pdf]
EPJC(2022)·7 citations
09
[Submitted on 7 Sept 2022] (cross-list from hep-ph)
Particle species and energy dependencies of freeze-out parameters in high-energy proton-proton collisions
Muhammad Waqas🇨🇳 · Guang Xiong Peng🇨🇳 · Fu-Hu Liu🇨🇳 · Muhammad Ajaz🇵🇰 · Abd Al Karim Haj Ismail🇦🇪 · Khusniddin K. Olimov🇺🇿 · Abdel Nasser Tawfik🇪🇬
We used blast wave model with Tsallis statistics to analyze the experimental data measured by ALICE Collaboration in proton-proton collisions at Large Hadron Collider and extracted the related parameters (kinetic freeze-out temperature, transverse flow velocity and kinetic freeze-out volume of emission source) from transverse momentum spectra of the particles. We found that the kinetic freeze-out temperature and kinetic freeze-out volume are mass dependent. The former increase while the latter decrease with the particle mass which is the evidence of a mass as well as volume differential kinetic freeze-out scenario. Furthermore we extracted the mean transverse momentum and initial temperature by an indirect method and observed that they increase with mass of the particles. All the above discussed parameters are observed to increase with energy. Triton ( $t$ ), hyper-triton ( $_{Λ ˉ}^{3} H$ ) and helion ( $^{3} H e$ ) and their anti-matter are observed to freeze-out at the same time due to isospin symmetry.
Comments:
13 pages, 5 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2209.03030 [pdf]
Eur.Phys.J.Plus(2022)·6 citations
10
[Submitted on 7 Sept 2022] (cross-list from gr-qc)
Neutron Star Crust Can Support A Large Ellipticity
J. A. Morales🇺🇸 · C. J. Horowitz🇺🇸
Non-axisymmetrical deformations of the crust on rapidly rotating neutron stars are one of the main targets of searches for continuous gravitational waves. The maximum ellipticity, or fractional difference in moments of inertia, that can be supported by deformations of the crust (known as "mountains") provides an important upper limit on the strength of these continuous gravitational wave sources. We use the formalism of Gittins et al 2021, along with a deforming force that acts mainly in the transverse direction, to obtain a maximum ellipticity of 7.4 $\times$ 10 $^{- 6}$ . This is larger than the original results of Gittins et al 2021 but consistent with earlier calculations by Ushomirsky et al 2000. This suggests that rotating neutron stars could be strong sources of continuous gravitational waves.
Comments:
9 pages, 5 figures, minor revisions MNRAS in press
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2209.03222 [pdf]
MNRAS(2022)·52 citations
11
[Submitted on 7 Sept 2022] (cross-list from hep-ph)
Report of the Topical Group on Neutrino Properties for Snowmass 2021
Carlo Giunti🇮🇹 · Julieta Gruszko🇺🇸 · Benjamin Jones🇺🇸 · Lisa Kaufman🇺🇸 · Diana Parno🇺🇸 · Andrea Pocar🇺🇸
Neutrinos are the most elusive among the known elementary particles, because of their feeble interactions with ordinary matter. They are also the most mysterious, because of their tiny masses that suggest a novel mass generating mechanism, their unknown Dirac or Majorana nature, and their big quantum mixing leading to large-amplitude flavor oscillations. This Topical Group focuses on neutrino properties that are not directly investigated in other Topical Groups of the Neutrino Frontier: in particular, the absolute value of the neutrino masses, the Dirac or Majorana nature of neutrinos, their electromagnetic properties, their lifetime, and hypothetical exotic properties.
Comments:
Topical Group Report for NF05 (Neutrino Frontier Topical Group on Neutrino Properties) for Snowmass 2021. 51 pages excluding references
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2209.03340 [pdf]
15 citations

Affiliations

first authorsco-authorsvia INSPIRE