Nuclear Theory·nucl-th

Wednesday·January 22, 2025

23 papers—9 primary·14 cross-listed

01
[Submitted on 17 Jan 2025]
Constituent Quark-model for BaryonsTh. Harmonic confinement and Two-body Meson-exchange Potentials
Th.A. Rijken🇳🇱
Soft Two-body potentials between the constituent quarks of the nucleon are derived using harmonic oscillator, i.e. gaussian, quark wave-functions. The gaussian wave-functions are very suited for applications with the ESC soft-core interactions, which employ gaussian form factors. In these notes using the Fourier transformation to momentum space the local and non-local contributions of the potentials based on the ESC meson-quark-quark vertices are evaluated. Using the ESC16 parameters translated to the quark-level leads to parameter free two-body and three-body diquark and triquark meson-exchange interactions. Applications to the SU(3) baryon-octet states and the $Δ_{33}$ resonance are performed., within the CQM using a harmonic confinement potential, leading to a satisfactory picture with relativistic constituent quarks. We present two versioins for the $N - Δ$ splitting: (i) model A with the instanton interaction, and (ii) model B with a large color-magnetic interaction from an almost point like OGE. The size of the baryons $\approx$ 1 fm.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2501.10497 [pdf]
0 citations
02
[Submitted on 17 Jan 2025]
Unnuclear matter at large-charge
Silas R. Beane🇨🇭 · Domenico Orlando🇨🇭 · Susanne Reffert🇨🇭
The utility of the non-relativistic large-charge EFT for physical systems, and neutron matter in particular, relies on controlled Schrödinger-symmetry breaking deformations due to scattering length and effective-range effects in the two-body system. A recently-found exact solution of the large-charge system is used to compute these effects for two-point correlation functions of large-charge operators in perturbation theory around the large-charge ground state. Notably, the leading effective-range effects are found to enter at second order in the effective range, in agreement with analogous calculations in the three-body system. The Schrödinger-symmetry breaking deformations are used -- together with input from Quantum Monte Carlo simulations -- to address the range of validity of the EFT with deformations both in general and in the special case of neutron matter. In particular, it is found that nuclear reactions with up to six low-energy neutrons in the final state can be described by the large-charge EFT with Schrödinger-symmetry breaking.
Comments:
49 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2501.10505 [pdf]
PRD(2025)·5 citations
03
[Submitted on 18 Jan 2025]
The 3 $α$ correlations of ground and excited $0^{+}$ states of $^{12} C$ within the microscopic cluster model
De-Ye Tao · Bo Zhou · Yu-Gang Ma
The cluster structures of the $0^{+}$ states in $^{12} C$ , including the ground state, the Hoyle state, and the recently identified $0_{3}^{+}$ and $0_{4}^{+}$ states, are analyzed to explore the cluster configurations and $3 α$ correlations without assuming the existence of $^{8} Be$ . In particular, the key quantity -- two-cluster overlap amplitudes -- is calculated for the $3 α$ clustering channels to reveal the essential features of these $0^{+}$ states. The results clearly show the distinction between the compact structure of the ground state and the gas-like structures of the excited $0^{+}$ states. The Hoyle state exhibits the expected gas-like dominant ( $0 S$ ) configuration, while the $0_{3}^{+}$ state shows a more extended $3 α$ clustering structure, which can be viewed as a breathing-like excitation of the Hoyle state, with an additional nodal structure. The $0_{4}^{+}$ state is found to have a mixed configuration, featuring a bent-arm-like structure in the $S \otimes S$ channel and an enhanced $2 α$ correlation in the $D \otimes D$ channel.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2501.10664 [pdf]
PRC(2025)·5 citations
04
[Submitted on 19 Jan 2025]
Typical new spherical-like $γ$ -soft spectra in $^{104, 106, 108}$ Pd
Tao Wang
To solve the Cd puzzle (spherical nucleus puzzle), I have proposed a new spherical-like $γ$ -soft nucleus. Since shape coexistence often occurs in such nuclei, explicit spherical-like $γ$ -soft spectra are not easily identified. In this paper, I finally find the direct evidence for the existence of the new spherical-like $γ$ -soft nucleus. $^{106}$ Pd is in fact a typical spherical-like $γ$ -soft nucleus. The low-lying parts, up to the $1 0_{1}^{+}$ state, under 4000 keV, of the spherical-like $γ$ -soft spectra are verified. The B(E2) values and the quadrupole moments of the low-lying levels are also studied. By comparison, the new spherical-like $γ$ -soft mode is confirmed. Moreover $^{104, 108}$ Pd are also discussed. These results completely disprove the possibility of the phonon excitations of the spherical nucleus in the Cd-Pd nuclei region.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2501.10925 [pdf]
4 citations
05
[Submitted on 20 Jan 2025]
Some insights on the partonic collectivity in heavy-ion collisions
Rajeev Singh🇷🇴
Elliptic flow and Number of Constituent Quarks scaling provide crucial insights into the underlying dynamics and degrees of freedom in heavy-ion collisions. This article provides some insights on the transition from hadronic to partonic collectivity, revealing possible key signatures of medium evolution. At low energies around ( $s_{NN} \leq 4.0$ GeV), $v_{2}$ may be negative and NCQ scaling might break down. We expect that as the collision energy rises beyond 4.0 GeV, $v_{2}$ may become positive and NCQ scaling gradually restores. The transition in $v_{2}$ behavior, coupled with the breakdown and restoration of NCQ scaling, highlights the increasing significance of partonic interactions at higher energies, marking the onset of partonic collectivity and the emergence of quark-gluon plasma (QGP)-like properties.
Comments:
Added physics reasoning and references
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2501.11290 [pdf]
Springer Proc.Phys.(2026)·1 citation
06
[Submitted on 20 Jan 2025]
Complex-scaled no-core shell model calculations of bound and unbound nuclear states in light nuclei
A.T. Kruppa · N. Michel · Xin-le Shang · Wei Zuo
The complex scaling method is commonly used to describe decaying states, but its applications are limited because the Hamiltonian operator must contain only relative coordinates. This has hindered the use of complex scaling in models defined with laboratory single-particle coordinates, and in particular one of the most important model in low-energy nuclear physics, the no-core shell model. We will then present a straightforward procedure for introducing complex scaling in the no-core shell model in order to calculate nuclear resonance states. For that matter, the complex-scaled two-body matrix elements must firstly be determined, and the resulting many-body Hamiltonian complex symmetric matrix must be diagonalized afterwards. Applications pertain to the bound ground states of the lightest nuclei $^{2} H$ , $^{3} H$ , $^{3} He$ , and $^{4} He$ , as well as the resonance ground states of $^{5}$ He and $^{5}$ Li, whereby the realistic interaction Daejeon16 is utilized.
Comments:
12 pages, 4 figures, published in Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2501.11294 [pdf]
PRC(2026)·3 citations
07
[Submitted on 20 Jan 2025]
Dynamical Electromagnetic fields and Dynamical Electromagnetic Anomaly in heavy ion collisions at intermediate energies
Irfan Siddique🇨🇳 · Anping Huang🇨🇳 · Mei Huang🇨🇳 · Muhammad Abdul Wasaye🇨🇳
Electromagnetic field produced in non-central heavy ion collisions play a crucial role in phenomena such as chiral anomalous effects, directed flow of mesons and splitting of spin polarization of $Λ/ Λ ˉ$ . A precise description of these fields is essential for quantitatively studying these effects. We investigate the space-time evolution of the electromagnetic fields by numerically solving Maxwell's equations using the results from the UrQMD model, rather than relying on an ansatz. We present the space-averaged dynamic electromagnetic fields, weighted by energy density, in the central region of heavy-ion collisions. These measurements can serve as a barometer for assessing the effects induced by magnetic fields. Comparing the fields at geometric center of the collisions, the space-averaged dynamical fields weighted by the energy density are smaller at the early stage but damp much slower at the later stage. We discuss the impact of these space averaged dynamical magnetic fields on the spin polarization and spin alignment in heavy ion collisions. Additionally, we explore the opportunity to study non-perturbative regime of Quantum Electrodynamics (QED) by presenting the simulation results for space averaged dynamical electric field at intermediate collision energies. Finally, the space-averaged dynamical electromagnetic anomaly $E$ $\cdot B$ weighted by energy density is also calculated and compared with experimentally measured slope parameter $r$ .
Comments:
11 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2501.11328 [pdf]
PRC(2025)·4 citations
08
[Submitted on 20 Jan 2025]
Beta-delayed particle emission and collective rotations
K. Riisager · E.A.M. Jensen · A.S. Jensen
Beta-delayed proton emission in the lower half of the sd-shell will involve deformed nuclei. We derive the normalized matrix element connecting emission of one particle from an initial rotational nuclear state to another final rotating state, and we extract selection rules involving the $K$ quantum number. The initial state is approximated as having a core identical to the final nuclear state. The formalism is then directly applicable to $β^{+}$ -delayed proton decays of even- $Z$ , odd- $N$ nuclei or $β^{-}$ -delayed neutron decays of odd- $Z$ , even $N$ nuclei. These beta-decay results are compared to the outcomes of possible transfer reactions. As an example the beta-delayed proton emission of $^{21}$ Mg is considered, where new quantum numbers can be assigned to several states in $^{21}$ Na.
Comments:
12 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2501.11458 [pdf]
EPJA(2025)·0 citations
09
[Submitted on 21 Jan 2025]
Light clusters as a possible source of crustal impurities: a quasi-particle approach
Helena Pais🇵🇹 · Hoa Dinh-Thi🇺🇸 · Anthea F. Fantina🇫🇷 · Francesca Gulminelli🇫🇷 · Constança Providência🇵🇹
The presence of impurities in the neutron star crust is known to affect in an important way the thermal and electrical conductivity of the star. In this work, we explore the possibility that such impurities might arise from the simultaneous presence of heavy ions together with Hydrogen and Helium isotopes formed during the cooling process of the star. We consider an equilibrium population of such light particles at temperatures close to the crystallization of the crust within an effective quasi-particle approach including in-medium binding energy shifts, and using different versions of the relativistic mean field approach for the crustal modeling. Thermal effects are consistently included also in the dominant ion species present in each crustal layer described in the compressible liquid drop approximation. We find that the impurity factor associated to light clusters is comparatively very small and can be neglected in transport calculations, even if a strong model dependence is observed.
Comments:
12 pages, 8 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2501.12064 [pdf]
Astron.Astrophys.(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE