Nuclear Theory·nucl-th

Thursday·September 11, 2025

13 papers—9 primary·4 cross-listed

01
[Submitted on 9 Sept 2025]
Wave-Breaking Phenomena in Quark-Gluon Plasma
Biswarup Paul🇮🇳
We investigate the onset of wave-breaking in the quark-gluon plasma (QGP) formed in heavy-ion collisions at both RHIC and the LHC. A nonlinear longitudinal color field is coupled to a three-dimensional viscous hydrodynamic background constrained by experimental conditions: Pb-Pb at $s_{NN} = 5.02$ TeV (LHC) and Au-Au at $s_{NN} = 200$ GeV (RHIC). The instantaneous wave-breaking threshold is determined from the in-medium plasma frequency, while the field evolution follows a nonlinear Landau equation with Debye screening and expansion damping. At the LHC, the higher initial temperature and density drive the system above the threshold within $τ ≲$ 2.3 fm/ $c$ , whereas at RHIC the cooler and more dilute medium delays wave-breaking to $τ ≃ 2.8$ ~fm/ $c$ . Scans over initial temperature, density, thermalization time, QGP lifetime, and collision system (RHIC vs LHC) confirm the robustness of this instability against parameter variations. These results identify wave-breaking as a universal microscopic mechanism for the early loss of coherence and rapid onset of hydrodynamics in the QGP, providing a common explanation for the fast equilibration observed at both RHIC and the LHC.
Comments:
4 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2509.08130 [pdf]
0 citations
02
[Submitted on 10 Sept 2025]
The IBM Description of the B(E2) Anomaly: Dynamical Triaxiality and Configuration Mixing
Wei Teng · Sheng Nan Wang · Xian Zhi Zhao · Yu Zhang
A theoretical investigation has been carried out to examine the effects of dynamical triaxility and configuration mixing on the $B (E 2)$ anomaly, characterized by $B_{4/2} = B (E 2; 4_{1}^{+} \to 2_{1}^{+}) / B (E 2; 2_{1}^{+} \to 0_{1}^{+}) < 1.0$ and $R_{4/2} = E (4_{1}^{+}) / E (2_{1}^{+}) \geq 2.0$ , within the framework of the interacting boson model (IBM). The results indicate that the effective $γ$ deformation may undergo substantial changes with increasing angular momentum in the $B (E 2)$ anomaly system governed by an IBM Hamiltonian involving rotor-like terms. Further calculations reveal that mixing between normal and intruder states may facilitate the emergence of $B (E 2)$ anomaly, thereby providing additional theoretical insights into this unusual phenomenon.
Comments:
11 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.08240 [pdf]
NPA(2025)·5 citations
03
[Submitted on 10 Sept 2025]
Triaxial rotor modes in finite-N boson systems
Yu Zhang · ShengNan Wang · Feng Pan · Chong Qi · J P Draayer
We propose an algebraic approach to elucidate the dynamic characteristics of triaxial rotor modes in nuclei by mapping a triaxial rotor Hamiltonian to the interacting boson model (IBM) one within a finite- $N$ framework. Our method unveils striking features not observed in conventional modes, exemplified by the $B (E 2)$ anomaly, characterized by $B (E 2; 4_{1} - - 2_{1}^{+}) / B (E 2; 2_{1} - - 0_{1}^{+}) << 1$ . Using specific examples, we demonstrate that the peculiar properties of low-lying states in both neutron-rich and neutron-deficient Os nuclei can be comprehensively understood through the proposed Hamiltonian, which incorporates both rigid and soft triaxial rotor modes. This algebraic method not only offers fresh insights into triaxial dynamics but also showcases its capability in uncovering emergent exotic collective modes in nuclear structure.
Comments:
10 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.08261 [pdf]
PRC(2024)·22 citations
04
[Submitted on 10 Sept 2025]
Nuclear Mass Predictions Using a Neural Network with Additive Gaussian Process Regression-Optimized Activation Functions
H. X. Liu🇨🇳 · S. Manzhos🇯🇵 · X. H. Wu🇨🇳
Nuclear masses are machine-learned as a function of proton and neutron numbers. The neural network with additive Gaussian process regression-optimized activation functions (GPR-NN) method is employed for the first time for this purpose. GPR-NN combines the advantages of both neural networks and Gaussian process regression, in that it possesses the expressive power of an NN, in principle allowing modeling any kind of dependence of nuclear mass on the features, and robustness of a linear regression with respect to overfitting. A study of the GPR-NN approach for interpolation and extrapolation in nuclear mass predictions is presented. It is found that the optimal hyperparameters for the GPR-NN approach in interpolation and extrapolation are different. If an appropriate set of hyperparameters is adopted, the GPR-NN approach can achieve good extrapolation performance for nuclear mass prediction, which could potentially help improve the mass predictions of a large number of currently experimentally unknown nuclei.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.08314 [pdf]
PRC(2026)·0 citations
05
[Submitted on 10 Sept 2025]
Renormalizability and nonrenormalizability of nonlocal potentials
N. Jacobi · A. M. Gasparyan · E. Epelbaum
We consider separable toy models of the nucleon-nucleon interaction inspired by chiral effective field theory. We show that nonlocality of the long-range forces causes the need for nonlocal counter terms, or even makes the whole approach nonrenormalizable.
Comments:
8 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.08512 [pdf]
PRC(2025)·0 citations
06
[Submitted on 10 Sept 2025]
A comprehensive view of nuclear shapes, rotations and vibrations from fully quantum mechanical perspectives
Takaharu Otsuka🇯🇵
The nuclear quadrupole collective states at low excitation energies are described in a novel, fully quantum mechanical and systematic manner as compared to traditional pictures initiated by Aage Bohr. The ellipsoidal shapes are shown to be triaxial in virtually all strongly deformed nuclei, in contrast to the Ansatz of axially symmetric shapes. The rotational bands of such triaxially deformed nuclei are described in a fully quantum mechanical way, i. e., without resorting to quantized free rotation of rigid body. The excitation energies within a rotational band, exhibiting the $J (J + 1)$ dependence on angular momentum $J$ , are shown to basically represent the change of binding energies due to nuclear forces. This differs from the interpretation á la Aage Bohr as rotational kinetic energies. The $K$ quantum numbers are shown to be practically conserved for triaxial ellipsoids, which turned out to be a real but positive surprise to many people in the field. The so-called $γ$ bands are shown to be $K$ =2 $^{+}$ rotations rather than $γ$ -vibrations, leading to a nice description of the so-called $γ γ$ 4 $^{+}$ state as a $K$ =4 $^{+}$ rotation. Vibrational modes are also shown to emerge in this study. Thus, the whole picture of low-energy quadrupole collective motion of heavy nuclei has been renewed in a fully quantum mechanical fashion, which differs from the traditional picture but appears to be simpler and more natural.
Comments:
10 pages, 7 figures, to appear in the Proceedings of the 14th Int. Spring Seminar on Nuclear Physics: "Cutting-edge developments in nuclear structure physics" to be published in EPJ Conference proceedings series. Only typos have been corrected from the previous version
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2509.08552 [pdf]
EPJ Web Conf.(2025)·3 citations
07
[Submitted on 10 Sept 2025]
Lattice calculation of the Sn isotopes near the proton dripline
Fabian Hildenbrand · Serdar Elhatisari · Ulf-G. Meißner · Helen Meyer · Zhengxue Ren · Andreas Herten · Mathis Bode
We present the first $ab initio$ lattice calculations of the proton-rich tin isotopes $^{99}$ Sn to $^{102}$ Sn using nuclear lattice effective field theory with high-fidelity two- and three-nucleon forces. For a given set of three-nucleon couplings, we reproduce binding energies with $\sim 1%$ accuracy for the even-even systems, and obtain energy splitting and two-nucleon separation energies in agreement with experiment. Our results confirm the $N = 50$ shell closure and reveal that the binding energy of $^{99}$ Sn lies below values extrapolated from heavier isotopes.
Comments:
6 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2509.08579 [pdf]
PRL(2026)·13 citations
08
[Submitted on 10 Sept 2025]
NuLattice: Ab initio computations of atomic nuclei on lattices
M. Rothman · B. Johnson-Toth · G. Hagen · M. Heinz · T. Papenbrock
We introduce NuLattice, a Python software package for ab initio computations of atomic nuclei on lattices. The computational tools consist of Hartree Fock, the coupled cluster method, the in-medium similarity renormalization group, and full configuration interaction. At present, the employed interactions are from pion-less effective field theory at leading order and consist of two-body and three-body contacts. We present results for light nuclei $^{2}$ H, $^{3, 4}$ He, $^{8}$ Be, $^{12}$ C, and $^{16}$ O. NuLattice algorithms exploit the sparsity and locality of lattice interactions, and as a result computations can be run on laptops.
Comments:
15 pages, 5 figures, 5 tables, associated Python package available at https://github.com/NuLattice, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.08771 [pdf]
EPJA(2026)·7 citations
09
[Submitted on 10 Sept 2025]
Two-particle two-hole excitations in semi-inclusive neutrino-nucleus scattering
Valerio Belocchi🇮🇹 · Maria Benedetta Barbaro🇮🇹 · Arturo De Pace🇮🇹 · Marco Martini🇫🇷
A calculation of the two-particle two-hole contribution to the semi-inclusive $(ν_{μ}, μ^{-} N)$ cross section on carbon is performed in the framework of the relativistic Fermi gas model. The process is driven by meson-exchange currents encompassing all contributions involving the exchange of a single pion and the excitation of a $Δ$ resonance. The calculation is validated against the inclusive $(ν_{μ}, μ^{-})$ response functions already existing in the literature, and then extended for the first time to the semi-inclusive channel. Results are presented both at fixed neutrino energy and folded with the T2K neutrino flux.
Comments:
35 pages, 21 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.08786 [pdf]
PRD(2025)·5 citations
10
[Submitted on 9 Sept 2025] (cross-list from hep-ph)
GUMP1.0 -- First global extraction of generalized parton distributions from experiment and lattice data with NLO accuracy
Yuxun Guo🇺🇸 · Fatma P. Aslan🇺🇸 · Xiangdong Ji🇺🇸 · M. Gabriel Santiago🇺🇸
We report the first global extraction of generalized parton distributions (GPDs), GUMP1.0, by combining deeply virtual Compton scattering and $ρ$ -meson production data from Jefferson Lab and Hadron-Electron Ring Accelerator with global fits of parton distribution functions, charge form factors, and lattice quantum chromodynamics simulations. Using a conformal moment space parametrization, we achieve a unified description across low- and high- $x$ regions at next to leading order (NLO) accuracy in perturbative corrections. The results provide state-of-the-art GPDs consistent with almost all known facts, enabling three-dimensional nucleon imaging in impact parameter space and, at the same time, establishing a benchmark for future theoretical and experimental studies of the nucleon structure.
Comments:
7 pages, 5 figures + 9-page supplemental
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2509.08037 [pdf]
PRL(2025)·36 citations
11
[Submitted on 9 Sept 2025] (cross-list from hep-ph)
Imaging the Jet-Induced Medium Response with Energy Correlators
Hannah Bossi🇺🇸 · Arjun Kudinoor🇺🇸 · Ian Moult🇺🇸 · Daniel Pablos🇪🇸 · Ananya Rai🇺🇸 · Krishna Rajagopal🇺🇸
Quark-gluon plasma (QGP), when viewed at length scales of order the inverse of its temperature, behaves as a strongly-coupled liquid. However, when it is probed with sufficiently high momentum transfer, asymptotic freedom mandates the presence of quark- and gluon-like quasi-particles. High energy partons within jets can trigger these high-momentum exchanges, making jets valuable probes for revealing the presence of such quasi-particles. Such elastic scatterings are implemented in the Hybrid Model, where a jet parton that scatters is deflected, kicking a medium parton, which recoils. Before and after a scattering, as one and then both partons propagate through the medium, they lose energy and momentum, exciting wakes in the QGP droplet. We use two-point and three-point energy-energy correlators (EECs) to reveal the relevant angular regions at which (modified) parton showers and wakes in the QGP each dominate, offering a new way with which to visualize and constrain the corresponding dynamics. We compare our calculations to recent CMS and ALICE measurements of two-point EECs of charged-particle tracks in jets produced in PbPb collisions. We show that our calculations are closest to the experimental measurements when elastic scattering is included and when the elastically scattered recoil-partons produce their own wakes. We also propose a new variant of the measurement that is especially sensitive to jet wakes.
Comments:
5 pages, 3 figures, Contribution to the Proceedings of Quark Matter 2025, Frankfurt, Germany
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2509.08047 [pdf]
EPJ Web Conf.(2026)·3 citations
12
[Submitted on 10 Sept 2025] (cross-list from hep-ph)
$T \times μ$ phase diagram from a fractal NJL model
E. Megias🇪🇸 · A. Deppman🇧🇷 · V. S. Timóteo🇧🇷
We propose a $μ$ -dependent coupling for a fractal effective model (FNJL) to make the results for the phase diagram compatible with the experimental data and lattice QCD calculations. The $μ$ -dependence of the coupling, which accounts for gluon effects, is obtained by fitting the lattice QCD results for the pseudo-critical temperature with the fractal model. We then use the new effective coupling in order to compute the dynamical mass, the quark condensate, the thermal susceptibility and, finally, the $T \times μ$ phase diagram. We consider both extensive and non-extensive statistics, and with a slight variation in the $μ$ -dependent coupling parameters we provide a single result for our model which is able to describe incredibly well the data from STAR, considering the simplicity of the effective model.
Comments:
The authors do not agree regarding the theoretical consistency of the model and the future direction of this research
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2509.08396 [pdf]
0 citations
13
[Submitted on 10 Sept 2025] (cross-list from hep-ph)
Light Meson Resonances
J. R. Pelaez (U. Complutense de Madrid and IPARCOS)🇪🇸
We provide a modern pedagogical introduction to light mesons. We discuss their masses and widths, their classification into multiplets of isospin and flavor SU(3), as well as other quantum numbers, mixing schemes, observable states, and their disposition in Regge trajectories. We briefly introduce the relevant concepts of Quantum Chromodynamics, including confinement, chiral symmetry, and the relationship between poles and resonances. We discuss their interpretation in terms of quark-model ordinary quark-antiquark states or non-ordinary states like exotics, multiquarks, or glueballs. Finally, we comment on the open issues that are still under discussion.
Comments:
Commissioned for the Encyclopedia of Particle Physics. 40 pages, 8 figures. References and clarifications added, and typos corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2509.08648 [pdf]
9 citations

Affiliations

first authorsco-authorsvia INSPIRE