Nuclear Theory·nucl-th

Tuesday·June 9, 2026

30 papers—13 primary·17 cross-listed

01
[Submitted on 5 Jun 2026]
NICER Constraints on Low density Interpolation and High density Continuation in Neutron Star Equations of State
Federico Nola
We investigate whether current astrophysical data constrain not only the high density continuation of the neutron star equation of state, but also the low density matching procedure itself. To this end, we compare two low density branches propagated through a common high density extension and confront them with direct NICER mass-radius posteriors, a lower bound on the maximum mass, and an effective constraint on $Λ_{1.4}$ . We find that the observable predictions of the two branches remain strongly overlapping, while the NICER-informed posterior still induces a nontrivial constraint on the matching parameters. Current data therefore constrain primarily the shared continuation above $n_{1}$ , but also indirectly restrict the low-density matching sector.
Comments:
8 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2606.07731 [pdf]
0 citations
02
[Submitted on 5 Jun 2026]
Improving the Predictive Capability of the Fission Reaction Event Yield Algorithm ( $FREYA$ )
A. E. Tuckey · R. Vogt · D. Breitenmoser · S. D. Clarke · S. A. Pozzi · M. Devlin
We determine the optimal parameters for thermal neutron-induced fission of $^{233, 235}$ U and $^{239, 241}$ Pu in the complete event fission model $FREYA$ . First, we revisit and, in most cases, improve the prior values determined for spontaneous fission using a genetic algorithm. Our optimization procedure is then applied to thermal neutron-induced fission, replacing the empirically-chosen parameters previously employed in $FREYA$ . Finally, the optimized parameter values are used to make predictions for spontaneous and thermal neutron-induced fission observables not included in the fits. This work represents the first step in a broader program to study neutron-induced fission as a function of incident neutron energy, to systematically improve the performance of $FREYA$ , capturing any energy-dependent trends of the physics-based $FREYA$ parameters.
Comments:
22 pages, 20 figures, 11 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.07827 [pdf]
0 citations
03
[Submitted on 5 Jun 2026]
Clustering in hadrons and light nuclei from Lorentz boosted form factors
F.E. Rodríguez Barrera🇨🇴 · N. G. Kelkar🇨🇴
The determination of nuclear charge radii is crucial for understanding the internal structure of nuclei and their fundamental interactions. A persistent discrepancy, not only in the measured proton charge radius but also in the light nucleus charge radius, between electron scattering and muonic spectroscopy has fueled ongoing debates in nuclear and particle physics. Using this discrepancy, we revisit the role of one of the proposed solutions, namely the use of Lorentz-boosted nuclear form factors to find a subtle connection between the boost and the cluster structure of nuclei. By applying two distinct relativistic formalisms, namely the Licht-Pagnamenta and Mitra-Kumari approaches, we systematically analyze corrections to the moments of the density distributions in hadrons and nuclei. Our results demonstrate that boosting the form factors from the Breit to the rest frame of the nucleus not only assists in reconciling the spectroscopic and scattering measurements but also provides a method to infer on the quark and nucleon cluster configurations within nuclei.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2606.07829 [pdf]
NPA(2026)·0 citations
04
[Submitted on 6 Jun 2026]
The ABC classification of exotic nuclei: a proposal
L. Fortunato · A. Vitturi · G. Singh
The large number of existing nuclear species and the long list of their possible different exotic properties, such as presence of a halo (A), Borromean structure (B), clusterisation (C) and others, calls for a classification scheme that is universal, concise, categorical, informative, accessible and easily extensible. We provide here a first reasoned attempt to fill this gap with an abridged naming scheme, called $A B C$ , based on definitions and properties that characterise modern nuclear physics. We limit our chart to light isotopes with $Z \leq 10$ where most of these features appear presently.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.08026 [pdf]
0 citations
05
[Submitted on 6 Jun 2026]
A Dynamical Model of Light Halo Nuclei
Francisco Barranco · Gregory Potel · Enrico Vigezzi
We present a review of theoretical studies of the structure and reactions of N=7 and N=8 nuclei in the vicinity of 11Li, carried out within a framework based on Nuclear Field Theory. The coupling of valence nucleons to low-lying surface vibrations of the spherical core plays a central role, giving rise to self-energy processes that renormalize single-particle states and transfer form factors, as well as to an induced pairing interaction arising from the exchange of collective vibrations, which renormalizes the bare pairing force. Excitation spectra and cross sections for one- and two-nucleon transfer reactions populating states in the quasi-continuum are calculated and compared with available experimental data. Collective excitations in the particle-particle channel are investigated, with particular emphasis on Giant Pairing Vibrations and on their damping mechanisms arising from coupling to more complex configurations and continuum states. Comparisons with other theoretical schemes are also presented. We conclude that a coherent understanding of experimental data requires the detailed consideration of particle-vibration coupling effects.
Comments:
To be published in the Special Issue of Particles,https://www.mdpi.com/journal/particles/special_issues/Halo40, hosting selected papers from the International Symposium Commemorating the 40th Anniversary of the Halo Nuclei, Bejing, 12-16 October 2025
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.08177 [pdf]
Particles(2026)·0 citations
06
[Submitted on 6 Jun 2026]
Resonance Femtoscopy Beyond the On-Shell Approximation
Liang Zhang🇨🇳 · Tianhao Shao🇨🇳 · Song Zhang🇨🇳 · Kai-Jia Sun🇨🇳 · Yu-Gang Ma🇨🇳
The observed shift of the $Δ (1232)$ resonance peak in $π$ - $p$ femtoscopic correlations challenges the conventional Breit-Wigner description of resonances in femtoscopy. We revisit the Koonin-Pratt framework by formulating femtoscopy in the momentum-space representation. By employing the T-matrix approach to disentangle on-shell and off-shell contributions, we show that the finite spatial extent of the emission source naturally induces sensitivity to off-shell scattering dynamics. Using a Friedrichs-Lee model constrained by low-energy $π$ - $p$ scattering data, we numerically demonstrate that this off-shell sensitivity leads to a peak shift accompanied by a dip on the high-momentum side of the peak. The predicted high-momentum side dip is absent in the data, pointing to source properties beyond the simple Gaussian approximation.
Comments:
main text: 6 pages, 3 figures supplement: 8 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2606.08230 [pdf]
2 citations
07
[Submitted on 6 Jun 2026]
On the effect of higher order symmetry energy corrections in Skyrme models for neutron star matter
Md. Emanuel Hoque · Arunava Mukherjee
Neutron stars consist of cold, dense, neutron-rich nuclear matter under charge neutrality and $β$ -equilibrium. In most nuclear equation of state (EOS) studies, the isospin dependence of asymmetric nuclear matter is described using the conventional quadratic/parabolic approximation to the nuclear symmetry energy. However, its validity in the highly neutron-rich inner core of neutron stars remains uncertain. In this work, we systematically investigate the role of higher-order isospin corrections to the symmetry energy within the framework of Skyrme-like effective nuclear interactions. We first analyze the standard SLy4 parametrization and quantify deviations arising from successive higher-order terms in the expansion of the energy per nucleon with respect to the isospin asymmetry parameter. We then extend the analysis to a large population of physically viable Skyrme EOSs sampled over a broad parameter space constrained by conventional nuclear saturation density bounds, thermodynamic stability, and causality, as well as the requirement to support astrophysical neutron-star mass observations exceeding $2 M_{⊙}$ . We find that higher-order isospin corrections become increasingly important at supra-nuclear densities and can significantly modify composition-sensitive quantities under $β$ -equilibrium, including the neutron-proton chemical potential difference, proton fraction, leptonic sector properties, and the direct-Urca process. In contrast, the $β$ -equilibrated EOS, energy density, pressure, and sound speed remain comparatively insensitive to these corrections for most viable EOSs. Our results demonstrate that while the quadratic approximation captures bulk thermodynamic behavior reasonably well, higher-order isospin contributions play a non-negligible role in determining the detailed composition and microscopic properties of dense matter in neutron-star interiors.
Comments:
20 pages, 18 figures in main article; additional 4 pages, 5 figures in appendix; preprint: INT-PUB-26-023; updated texts figures and tables for clarification
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th)
arXiv:
2606.08250 [pdf]
0 citations
08
[Submitted on 7 Jun 2026]
Hierarchical Neural Filtering of Nuclear Mass Residuals and Spectral Signatures of Quantum Chaos
Jaskirat Singh · Chong Qi
In complex quantum many-body systems such as atomic nuclei, the interplay between regular collective motion and irregular intrinsic dynamics gives rise to fluctuations that cannot be fully captured by existing global theoretical models. Nuclear mass, which exhibits smooth trends across the nuclear chart together with localized deviations, provides a sensitive observable for investigating such irregular dynamics. In this work, we employ a variety of neural network architectures, which serve as controlled nonlinear filters within a Hierarchical Residual Decomposition framework to progressively extract and suppress the chaotic many-body signature (characterized by $1/ f$ spectral correlations) in nuclear mass residuals. The resulting Physics-Informed Neural Ensemble (PINE) model combines multiple mass models and neural network architectures, enabling a systematic suppression of coherent and chaotic components, after which the remaining fluctuations are analyzed using Fourier-based spectral diagnostics across different mass regions. Our results show that hierarchical neural residual learning efficiently removes the dominant low-frequency correlations and suppresses the quantum-chaotic spectral rigidity, driving the residuals toward the uncorrelated white-noise limit. This systematic suppression provides a quantitative diagnostic of the underlying scale-dependent complexity and many-body correlation structure of nuclear mass deviations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.08546 [pdf]
0 citations
09
[Submitted on 8 Jun 2026]
Nuclear matrix element of $2 ν β β$ decay of $^{76}$ Ge: roles of high-lying states and two-body currents
Hua-Yang Xu🇨🇳 · Hao Zhou🇨🇳 · Long-Jun Wang🇨🇳
We present a microscopic analysis of the nuclear matrix element (NME) of the two-neutrino double- $β$ ( $2 ν β β$ ) decay for open-shell heavy deformed nuclei, taking into account the fact that nuclear level density increases rapidly with excitation energy as well as the contribution of two-body current (2BC). Taking $^{76}$ Ge $\to$ $^{76}$ Se decay as an example, we found that due to the rapid increase of the level density of the intermediate nucleus $^{76}$ As with excitation energy $E_{n}$ , the single- $β$ Gamow-Teller (GT) matrix elements become highly fragmented with very small magnitude, and exhibit seemingly random sign patterns at high $E_{n}$ region. This leads to an effective cancellation at high $E_{n}$ region in calculating the $2 ν β β$ NME which then turns out to converge at $E_{n} ≲ 5$ MeV, indicating that the contribution of high-lying states of the intermediate nucleus to $2 ν β β$ NME is negligible. Besides, the 2BC in the transition operator is found to contribute $\sim 10%$ quenching to the $2 ν β β$ -decay NME of $^{76}$ Ge.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.08954 [pdf]
0 citations
10
[Submitted on 8 Jun 2026]
Systematic study of the half-lives of nuclear bound-state $β^{-}$ decay
Jing-Wen Ran · Long-Jun Wang
Nuclear bound-state $β^{-}$ decay ( $β_{b}$ decay) is a novel weak-interaction process that becomes possible when atoms are highly ionized, such as in stellar environments or heavy-ion storage rings. In this work we present a systematic theoretical calculations for the $β_{b}$ -decay half-lives of interesting candidates for the first time, where both allowed Gamow-Teller transitions and first-forbidden transitions are taken into account by the microscopic projected shell model, and the lepton phase space is calculated by the Takahashi-Yokoi model. We analyzed the structure informations for hundreds of nuclei near the $β$ -stability line, and select 16 interesting candidates belonging to two categories, i.e., nuclei with negative $Q$ values and positive $Q$ values in neutral atoms respectively. Among these candidates, we recommend $^{243} Am^{95 +}$ , $^{194} Os^{76 +}$ , $^{227} Ac^{89 +}$ , $^{228} Ra^{88 +}$ , $^{241} Pu^{94 +}$ , $^{247} Cm^{96 +}$ and $^{250} Cm^{96 +}$ as promising ones for future studies of storage-ring experiments because their $β_{b}$ -decay half-lives are predicted to be much shorter than the half-lives in neutral atoms. These findings provide essential nuclear inputs for astrophysical models and identify specific candidates where experimental verification would be most valuable.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.08963 [pdf]
0 citations
11
[Submitted on 8 Jun 2026]
Hyperon polarization in isobaric Zr+Zr collisions at $s_{N N} = 200$ GeV: TRENRo3D + CLVisc with an initial longitudinal flow gradient
Ze-Fang Jiang🇨🇳 · Xiang Fan🇩🇪 · Jing Jing🇨🇳
We present a theoretical study of global and azimuthal-angle-dependent $Λ$ hyperon polarization in isobaric $_{40}^{96}$ Zr+ $_{40}^{96}$ Zr collisions at $s_{N N} = 200$ ~GeV using the TRENTo3D initial condition model coupled to the (3+1)-D viscous hydrodynamic model CLVisc. A longitudinal flow velocity gradient, controlled by $f_{v}$ , is introduced into TRENTo3D for the first time, providing an essential source of initial vorticity in this symmetric isobaric system. Within the isothermal polarization framework, the model provides a simultaneous description of STAR measurements of the global polarization $- P^{y}$ (centrality, $p_{T}$ , and $η$ dependences) and the azimuthal modulation coefficients $P_{y, c0}$ and $P_{y, c2}$ . The $p_{T}$ dependence reflects the competition between thermal vorticity and shear contributions: the thermal term decreases with $p_{T}$ , while the shear term rises and increasingly shapes the curvature of the total polarization. In this decomposition, $P_{y, c2}$ is dominantly shear-driven and serves as a clean probe of shear-induced polarization. Scans of $f_{v}$ , $k_{T}$ , and nuclear structure provide complementary constraints on the initial state, while the bulk-viscosity dependence is also examined; the five nuclear structure configurations from the STAR isobar blind analysis yield nearly indistinguishable polarization. For $P_{z}$ , the isothermal scenario captures the azimuthal modulation but overpredicts the high- $p_{T}$ modulation amplitude, and comparison with the standard thermal treatment shows that neither scenario achieves a unified description of all observables.
Comments:
17 pages, 13 figures. We welcome any comments. If there are relevant references we may have overlooked, please don't hesitate to let us know and we'd be very grateful!
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.09093 [pdf]
0 citations
12
[Submitted on 8 Jun 2026]
Global Ab initio Neutrino Mass Limits from Neutrinoless Double-Beta Decay
T. Shickele🇨🇦 · L. Jokiniemi🇨🇦 · A. Belley🇨🇦 · J. D. Holt🇨🇦
We present global limits for Majorana neutrino masses by combining latest results from neutrinoless double-beta ( $0 ν β β$ ) decay searches and ab initio nuclear theory. Limits are derived in a Bayesian framework utilizing likelihood functions from a suite of $0 ν β β$ -decay experiments in conjunction with nuclear matrix elements calculated from nuclear and electroweak forces derived from chiral effective field theory and implemented in the in-medium similarity renormalization group many-body approach. In contrast to nuclear models, ab initio results indicate that the current generation of $0 ν β β$ -decay experiments have likely \textit{not} yet reached sensitivities required to probe the mass regime allowed by neutrino-oscillation data, where the combined bounds are notably stronger than those given by individual experiments. Finally, from predicted sensitivities of next-generation searches, we show that, while no one individual experiment fully covers the inverted mass ordering, this can be achieved from combined contributions from the four key isotopes: $^{76}$ Ge, $^{100}$ Mo, $^{130}$ Te, and $^{136}$ Xe.
Comments:
9 pages, 5 figures, accepted for publication in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2606.09288 [pdf]
PRD(2026)·2 citations
13
[Submitted on 8 Jun 2026]
Angular and Kinetic Properties of Scission Neutrons within Time-dependent Density Functional Theory
Antonio Bjelčić · Ibrahim Abdurrahman · Kyle Godbey
Scission-neutron emission is investigated in $^{235} U (n_{th}, f)$ , $^{239} Pu (n_{th}, f)$ and $^{252} Cf (sf)$ within time-dependent density functional theory. Using a substantially larger simulation domain than in previous studies, the angular and energy distributions of emitted scission neutrons are extracted over a specific range of emission angles. At these angles, scission neutrons are absent below a threshold energy of roughly $1.5$ -- $2 MeV$ , and instead contribute predominantly to the higher energy part of the prompt fission neutron spectrum. Combining the calculated scission-neutron spectrum with a Maxwellian model for the evaporated component, constrained by low-energy experimental data, reproduces the measured high-energy prompt-fission-neutron yield in both $^{239} Pu (n_{th}, f)$ and $^{252} Cf (sf)$ , whereas the evaporation-only model systematically underestimates it. This identifies a signature of scission neutrons already present in existing high-energy prompt fission neutron spectra and constitutes direct evidence for a non-negligible scission-neutron component in prompt fission neutron emission.
Comments:
5 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.09656 [pdf]
3 citations
14
[Submitted on 5 Jun 2026] (cross-list from hep-ph)
Open quantum system approach to the transverse momentum broadening of a colour dipole
François Arleo🇫🇷 · Pietro Benzoni🇫🇷 · Paul Caucal🇫🇷 · Pol Bernard Gossiaux🇫🇷
Using the open quantum systems formalism, we study the propagation of a quark-antiquark pair propagating through a dense QCD plasma of size $L$ and transverse momentum broadening transport coefficient $q^$ , and we derive the Lindblad evolution equation for the density matrix of the system. We focus on the boosted regime where the opening angle $θ_{q q ˉ}$ of this effective colour dipole satisfies $θ_{q q ˉ} ≪ 1$ . In the correlation limit where the quark-antiquark relative transverse momentum $p_{⊥}$ is much larger than the imbalance $q_{⊥}$ as well as the medium typical transverse momentum scale $Q_{s} = q^L$ , we demonstrate that the resulting Wigner distribution displays quasi factorisation between a hard factor describing the hard splitting producing the $q q ˉ$ pair and the transverse momentum imbalance $q_{⊥}$ -distribution encoding the broadening induced by the medium. The factorisation is violated by a "colour decoherence" factor that controls the $θ_{q q ˉ}$ dependence of the $q_{⊥}$ -distribution through the ratio $θ_{q q ˉ} / θ_{c}$ , with $θ_{c} \sim (q^L^{3})^{- 1/2}$ . The open quantum systems approach enables us to clarify the role of this critical angle $θ_{c}$ and its associated critical time $t_{c}$ in the genuine quantum decoherence of the density matrix in colour and kinematic space: in particular, $t_{c}$ controls both the suppression of the off-diagonal elements of the density matrix in colour space and the transition between singlet and octet states. We find, however, that colour decoherence sets in earlier than the full decoherence of the density matrix, thereby marking the onset of classical behaviour in the system. Finally, we investigate the corrections beyond the quasi-factorised picture due to the quantum diffusion term in $p_{⊥}$ of the Lindblad equation and we find that these corrections are mild.
Comments:
62 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.07744 [pdf]
2 citations
15
[Submitted on 5 Jun 2026] (cross-list from nucl-ex)
Short-range correlated pair formation and nuclear shell structure
D. Nguyen · C. Yero · H. Szumila-Vance · F. Hauenstein · N. Swan · L.B. Weinstein · J. Kahlbow · A. Schmidt · E. Piasetzky · O. Hen · C. Ayerbe Gayoso · E. Cohen and 17 other authors
Short-range correlated (SRC) nucleon pairs - caused by brief, high-momentum interactions between two nucleons - are dominated by neutron-proton pairs with large relative and smaller center-of-mass momenta. However, the underlying dynamics that determines which nucleons form such pairs remains uncertain. Previous measurements showed that proton pairing probabilities increased strongly with nuclear asymmetry N/Z, but could not rule out an increase with nuclear mass A. We measured high-missing-momentum protons knocked out in electron scattering from selected nuclei with a range of shell configurations, A, and N/Z, including 9Be, 10B, 11B, 12C, 40Ca, 48Ca, 54Fe and 197Au. Unexpectedly, we found that while the pairing probability increased with A, the slope of the increase was much greater from Be to C and from 40Ca to Fe, than from Be to Au. This shows the importance of long-range nuclear shell structure on the probability of short-range nucleon pairing.
Comments:
5 pages, 3 figures, to be submitted to Physics Review Letters
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.07754 [pdf]
1 citation
16
[Submitted on 6 Jun 2026] (cross-list from hep-ph)
First determination of vector and tensor couplings from polarized $π Δ$ photoproduction
Vanamali Shastry🇺🇸 · Łukasz Bibrzycki🇵🇱 · Vincent Mathieu🇪🇸 · Glòria Montaña🇪🇸 · Alessandro Pilloni🇮🇹 · César Fernández-Ramírez🇪🇸 · Robert J. Perry🇺🇸 · Arkaitz Rodas🇺🇸 · Adam P. Szczepaniak🇺🇸 · Daniel Winney🇲🇽
The couplings between hadrons encode the dynamics of quantum chromodynamics. While many couplings can be calculated from decay widths, in some cases the decays are kinematically forbidden and hence are not directly accessible. We use a Regge framework to determine these couplings from high-energy polarized scattering processes. We apply this to the $π Δ$ photoproduction that was recently studied at GlueX and provide the first determination of the complete set of $N Δ$ couplings to $ρ$ , $b_{1}$ , and $a_{2}$ .
Comments:
5 pages, 3 figues
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.07917 [pdf]
1 citation
17
[Submitted on 6 Jun 2026] (cross-list from hep-ph)
Retarded Correlators of Charge Transport in a Magnetic Field
Xuan Zhao🇨🇳 · Qiuze Sun🇨🇳 · Yi Wang🇨🇳 · Jin Hu🇨🇳
We study charge transport in a magnetized relativistic plasma using kinetic theory within the relaxation-time approximation. By exactly solving the linearized Boltzmann equation in a uniform magnetic field, we obtain an analytic solution for the distribution function in terms of Bessel functions. Using this solution, we compute the full set of retarded current-current correlators and verify the Ward identities. In the hydrodynamic limit, we extract the charge diffusion modes, demonstrating that the transverse diffusion coefficient is strongly suppressed by the magnetic field, scaling as $1/ B_{0}^{2}$ in the strong-field regime, while the longitudinal diffusion remains unaffected. Furthermore, we analyze the non-hydrodynamic branch cuts in the complex frequency plane, determining their kinematic thresholds and identifying the underlying wave-particle interactions as longitudinal Landau damping and transverse cyclotron damping.
Comments:
22 pages, 3 figures; comments welcome
Subjects:
High Energy Physics — Phenomenology (hep-ph); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
arXiv:
2606.08139 [pdf]
0 citations
18
[Submitted on 6 Jun 2026] (cross-list from hep-ph)
Lepton $g - 2$ non-universality of hadronic contributions and a sub-GeV window to New Physics
Siyuan Li🇩🇪 · Vladimir Pascalutsa🇩🇪 · Maxim Pospelov🇺🇸
We propose the linear combination of the anomalous magnetic moments of the muon and electron, $a_{μ - e} \equiv a_{μ} - (m_{μ} / m_{e})^{2} a_{e}$ , as a natural low-energy window quantity that may directly probe the current discrepancy between the data-driven and lattice-QCD evaluations of hadronic contributions. The rescaling ensures an exact cancellation of the short-range effects, thereby improving the UV behavior and bypassing a number of issues that arise in $a_{μ}$ or $a_{e}$ separately. The hadronic-vacuum-polarization effect in $a_{μ - e}^{HVP}$ , together with its uncertainty, is reduced as compared to $a_{μ}^{HVP}$ by $\sim 85%$ . This is promising for tests of New Physics, conditional to significant improvements in experimental measurements of $a_{e}$ and $α$ . One can foresee the improvements in tests of New Physics with some degree of flavor non-universality, as well as for the flavor-universal sub-GeV states.
Comments:
8 pages, 6 figures, 2 tables. Fixed typos and added references
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.08329 [pdf]
1 citation
19
[Submitted on 7 Jun 2026] (cross-list from hep-ph)
Principles and Possibilities for Bound States in Gauge Theory
Paul Hoyer🇫🇮
Bound states differ from scattering yet are not covered in textbooks on Quantum Field Theory. I discuss a perturbative method for QED and QCD based on canonical quantization. Fully fixing temporal gauge $A^{0} (t, x) = 0$ imposes Gauss' law on physical states. As pointed out by Dirac, this implies that electron states include a longitudinal gauge field $A_{L}$ , which determines the instantaneous bound state potential. The situation is analogous for quarks and gluons in QCD. An instantaneous confining potential arises for color singlet $q q ˉ$ states when a non-vanishing boundary condition on $A_{L}^{a} (x \to \infty)$ is specified in Gauss' constraint. As suggested by Gribov, $α_{s} (Q^{2})$ may freeze at a perturbative value when the confining potential dominates. Hadrons can then be calculated perturbatively. At vanishing quark mass there is a $j^{P C} = 0^{++}$ state with zero energy which can mix with the perturbative vacuum, giving rise to a spontaneous breaking of chiral symmetry.
Comments:
12 pages, 1 figure. Minor corrections from v1. The bound state equation is considered only in the rest frame
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.08489 [pdf]
0 citations
20
[Submitted on 7 Jun 2026] (cross-list from hep-ph)
Nuclear parton distributions and nuclear shadowing
Petja Paakkinen🇨🇭 · Vadim Guzey🇫🇮
In this contribution, we review the physics and phenomenology of nuclear parton distribution functions (PDFs), with a particular focus on the small-x region of nuclear shadowing. We summarise experimental evidence for nuclear modifications of PDFs and discuss their theoretical explanations; in particular, we contrast different models of nuclear shadowing. We also overview model-agnostic extractions of nuclear PDFs from global data on hard processes with nuclei, emphasizing the validity of collinear factorization and the dominance of leading-twist nuclear PDFs. Finally, we discuss perspectives for present and future precision studies of nuclear PDFs and small-x QCD dynamics, including photonuclear reactions in heavy-ion ultraperipheral collisions at the Large Hadron Collider and lepton-nucleus deep inelastic scattering at the future Electron-Ion Collider.
Comments:
21 pages, 8 figures; a contribution to the Encyclopedia of Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.08830 [pdf]
0 citations
21
[Submitted on 7 Jun 2026] (cross-list from cond-mat.stat-mech)
Time Evolution of Heat Conduction in a Generalized Model of Brownian Motion
T. Koide · F. Nicacio
We investigate the properties of heat conduction in a network of harmonic oscillators interacting with heat baths, described by a generalized model of Brownian motion. This model includes noise and dissipation terms in both the momentum and position equations. This generalization is motivated by the requirement of consistency with the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) equation. Because standard definitions of heat current based on velocity become mathematically inconsistent in this framework, we derive an analytical expression for the steady-state heat flow based on an extended framework of stochastic energetics. We confirm that Fourier's law (linear thermal response) is satisfied and that the model naturally captures microscopic thermal boundary resistance, analogous to Kapitza resistance. This demonstrates that our generalized model functions as a valid phenomenological framework for simulating non-equilibrium processes, marking a crucial step toward a unified formulation of stochastic and quantum thermodynamics. Furthermore, we analyze the time evolution of heat conduction by numerically solving the corresponding differential equations for the correlation functions. Unlike standard Brownian motion, the generalized model generates continuous and nowhere differentiable trajectories for both momentum and position (as is characteristic of overdamped dynamics). Finally, we show that the heat current exhibits characteristic transient behavior when the inter-particle interaction is switched on. Specifically, an instantaneous heat flow emerges, whose direction is strictly governed by whether the interaction is attractive or repulsive, significantly differing from the predictions of the standard model.
Comments:
17 pages, 16 figures
Subjects:
Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2606.08839 [pdf]
0 citations
22
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Five-flavor $u d sc b ˉ$ molecular pentaquarks from heavy-quark and local hidden gauge symmetries
Ratirat Suntharawirat🇹🇭 · Nongnaphat Ponkhuha🇹🇭 · Daris Samart🇹🇭
We study a family of genuinely exotic five-flavor molecular pentaquark states containing the five quark flavors $u, d, s, c, b$ that form experimentally accessible hadrons. We construct the meson-baryon interaction from the local hidden gauge symmetry combined with heavy-quark spin symmetry, following the chiral unitary description that reproduces the LHCb hidden-charm strange pentaquarks. Heavy-quark flavor symmetry allows us to obtain the $u d sc b ˉ$ sector by replacing the anti-charm quark in the meson with an anti-bottom quark while keeping the charm quark in the baryon. As a result, we obtain ten threshold-associated isoscalar poles with $J^{P} = 1/ 2^{-}, 3/ 2^{-}, 5/ 2^{-}$ in the range $7.72$ to $7.96$ GeV. They are narrow and organized into heavy-quark spin multiplets with predicted near-degeneracies. There are four states that overlap with the earlier two-sector study in the literature to about $2$ MeV, which shows that the separate-sector treatment is recovered as a limit of this work. Moreover, we also identify two additional, more deeply bound $B_{s} Λ_{c}$ and $B_{s}^{*} Λ_{c}$ poles generated by strong inter-channel coupling because these poles are farther from their dominated thresholds. This is an interesting signal that can be searched for at LHCb in the $B_{c} Λ$ and $B_{s}^{*} Λ_{c}$ invariant mass spectra.
Comments:
10 pages, 2 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.09202 [pdf]
1 citation
23
[Submitted on 8 Jun 2026] (cross-list from astro-ph.HE)
Bayesian analysis of the shear modulus in the neutron-star crust
T. Diverrès🇫🇷 · G. Montefusco🇫🇷 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷
The elastic properties of the neutron-star crust are important for the calculations of crustal modes. In particular, the ability of the crust to support shear stresses has been connected to observations of quasi-periodic oscillations and to crust deformations potentially emitting gravitational waves. In this work, we assess the uncertainties in the shear modulus and shear speed in the neutron-star outer and inner crust. To this aim, we performed a Bayesian analysis of the shear properties of the neutron-star crust at zero temperature starting from both a non-informative and a nuclear-physics-informed prior. For the treatment of inhomogeneous matter in the crust, we relied on the one-component plasma approximation, with a (semi-)classical treatment of the ions. We show that the use of a nuclear-physics-informed prior has a non-negligible impact on the prediction of the elastic properties of the crust. The frequency of the fundamental torsional crustal modes we obtain is compatible with the low-frequency range of observed quasi-periodic oscillations, our estimates lying in the interval $\approx 20 - 50$ ~Hz. Although the different considered priors lead to compatible results, the inclusion of nuclear-physics experimental information in the prior considerably reduces the uncertainties in the prediction of the elastic properties of the crust, potentially constraining the predicted frequency of the crustal modes.
Comments:
15 pages, 5 figures. Accepted in Astronomy & Astrophysics
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2606.09247 [pdf]
Astron.Astrophys.(2026)·0 citations
24
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Meson-Nucleus Bound States with Neural-Network Quantum States
Wei-Lin Wu🇨🇳 · Liang-Zhen Wen🇨🇳 · Shi-Lin Zhu🇨🇳
We present the first systematic calculations of $ϕ$ -, $η_{c}$ -, and $J / ψ$ -nucleus ground states up to mass number $A = 12$ based on the HAL QCD meson-nucleon potentials at near-physical point. The $(A + 1)$ -body Schrödinger equation is solved with a neural-network variational Monte Carlo framework, generalized to incorporate mesonic degrees of freedom. Benchmarking on light nuclei from $^{2}$ H to $^{12}$ C yields ground-state energies consistent with experiment. Meson-nucleus bound states emerge at $A \geq 2$ for $ϕ$ , $A \geq 4$ for $J / ψ$ , and $A \geq 6$ for $η_{c}$ . The $ϕ$ -nucleus systems exhibit the strongest binding, with binding energies reaching tens of MeV. The $J / ψ$ -nucleus and $η_{c}$ -nucleus systems are weakly bound at the few-MeV and sub-MeV scale, respectively. The binding energy per nucleon deepens nearly linearly with $A$ for charmonium systems, whereas the $ϕ$ -nucleus system exhibits a non-monotonic behavior peaking at $^{4}$ He -- a distinctive hallmark of the short-range and strongly attractive $ϕN$ interaction. The meson compresses the nucleon distribution relative to the parent nucleus, and evolves from a halo configuration to one embedded inside the nucleus with increasing $A$ . Our results provide predictions for future experimental searches, and establish a quantitative bridge between lattice QCD meson-nucleon interactions and the emergent many-body phenomena in meson-nucleus bound states.
Comments:
12 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.09254 [pdf]
0 citations
25
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Space- and time-like electromagnetic form factors of the $Ω$ baryon
L. Albino🇲🇽 · B. Almeida-Zamora🇪🇸 · A. Bashir🇪🇸 · J.J. Cobos-Martínez🇲🇽 · K. Raya🇪🇸 · J. Segovia🇪🇸
We present predictions for the elastic electromagnetic form factors of the $Ω$ baryon in both space-like and time-like regions, computed within a confining, symmetry-preserving framework based on a vector $\otimes$ vector contact interaction. The calculation is performed in the rainbow-ladder truncation of QCD's Dyson-Schwinger equations, combined with a Poincaré-covariant Faddeev equation for the three-quark bound state. The $Ω$ baryon, composed solely of strange quarks, provides a particularly clean environment in which to investigate the role of quark mass and SU(3)-flavor symmetry in shaping baryon structure. Within this approach, the electromagnetic current is constructed consistently with the Ward-Takahashi identity, yielding four independent form factors associated with the electric monopole, magnetic dipole, electric quadrupole, and magnetic octupole moments. We compute these form factors over a broad kinematic domain and analyze their behavior in both space-like and time-like regions. The resulting static electromagnetic moments and multipole form factors of the $Ω$ baryon exhibit a visible sensitivity to the dressed-quark anomalous magnetic moment, particularly in the magnetic and higher-order multipole sectors. The time-like form factors are obtained through asymptotic analytic continuation of the corresponding space-like solutions, allowing the construction of the effective form factor and its comparison with available experimental data and recent phenomenological analyses.
Comments:
13 pages, 8 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.09324 [pdf]
0 citations
26
[Submitted on 8 Jun 2026] (cross-list from astro-ph.HE)
Measuring radii of merging neutron stars with interface-mode asteroseismology informed by nuclear theory and experiment
Duncan Neill🇬🇧 · William G. Newton🇺🇸 · Jeremy W. Holt🇺🇸 · Christian Drischler🇺🇸 · Jérôme Margueron🇺🇸 · David Tsang🇬🇧
The structure and dynamics of neutron stars can be used to probe the physics of extreme matter at nuclear densities and beyond. Nucleonic matter up to ~2-3 times nuclear saturation density is well-studied by nuclear experiments and theoretical modelling. Matter beyond these densities may contain non-nucleonic degrees of freedom that determine the structure of the neutron star inner core and influence bulk observables like stellar radius. Neutron star radius is a key parameter for constraining the core equation of state, but is not a direct gravitational-wave observable during neutron star mergers. Here we show that, if nucleonic physics is well constrained at low densities, the frequency of the asteroseismic crust-core interface mode in a neutron star can be used to infer its radius to within 5-10%, in a way which is notably insensitive to the details of the inner core. This frequency can be measured through multimessenger coincident timing of resonant shattering flares, or direct observation of dynamical tidal resonance with next-generation gravitational-wave detectors. We show that improved constraints on low-density nucleonic physics by nuclear experimental and theoretical efforts will substantially improve such a radius measurement, leveraging low-density efforts for an improved understanding of physics at higher densities.
Comments:
Main text and appendices: 11 pages, 2 figures. Supplementary material: 12 pages, 8 figures. Submitted
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.09621 [pdf]
0 citations
27
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Effective QCD model with consistent quasi-gluon treatment : formulation and application
Chowdhury Aminul Islam · Munshi G. Mustafa · Rajarshi Ray · Pracheta Singha
The Polyakov loop enhanced Nambu-Jona-Lasinio model is reformulated in terms of the gluon quasi-particles in addition to the already existing quark quasi-particles. The formulation goes beyond the saddle point approximation for the gluon sector. The framework provides a physically consistent quasiparticle model for QCD thermodynamics. The ensuing advantages of this formulation is discussed using transport coefficients in the light quark sector.
Comments:
17 pages, 17 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.09633 [pdf]
0 citations
28
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Partial Pressure Contributions of Hadron Families to the QCD Equation of State
Jonathan Gonzales🇺🇸 · Alejandro Florez🇺🇸 · Johannes Jahan🇺🇸 · Angel R. Nava Acuna🇺🇸 · Naman Mehndiratta🇺🇸 · Claudia Ratti🇺🇸
Lattice simulations provide the thermodynamics of quantum chromodynamics (QCD) as a function of the temperature, at zero-to-moderate values of the baryonic chemical potential. However, the contribution of single hadronic species cannot be directly isolated from lattice calculations. In this work, we find linear combinations of up to fourth order susceptibilities which isolate the contribution of hadrons to the QCD pressure according to their baryon number $B$ , electric charge $Q$ and strangeness $S$ content. These combinations are valid, provided that the thermodynamics of a strongly-interacting gas in the low-temperature regime can be modeled as a gas of non-interacting hadrons and their resonances. Finally, we test the validity of these linear combinations in the Hadron Resonance Gas (HRG) model and compare them to available lattice QCD results, using continuum-estimated susceptibilities.
Comments:
9 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2606.09757 [pdf]
2 citations
29
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Einstein-de Haas effect and induced rotation in an evolving magnetized QCD matter
Dushmanta Sahu · Captain R. Singh
The Einstein-de Haas (EdH) effect describes the emergence of collective rotation driven by spin alignment under an external magnetic field. We investigate this effect in a dynamically expanding quark-gluon plasma (QGP) using a quasiparticle model (QPM). We compute the EdH-induced angular velocity $ω_{EdH}$ as a function of temperature, proper time, and fireball radius. Our results show that $ω_{EdH}$ grows with proper time and is consequently suppressed at higher temperatures. Near the QGP crossover temperature, $ω_{EdH}$ attains a substantial, non-negligible magnitude. We identify a nontrivial crossing between the strong and weak magnetic field regimes that reflects the competition between spin alignment and the energy required to sustain orbital motion. This nontrivial crossing temperature separates a spin-dominated regime from an inertia-dominated regime of magnetic field-induced rotation. These findings establish the EdH effect as a manifestation of angular momentum conservation in magnetized QCD matter.
Comments:
10 pages and 5 captioned figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.09760 [pdf]
1 citation
30
[Submitted on 8 Jun 2026] (cross-list from hep-ph)
Dispersive analysis of the $J / ψ \to γ π^{0} π^{0}$ process
Bai-Long Hoid🇩🇪 · Igor Danilkin🇩🇪 · Anna Testa🇩🇪 · Marc Vanderhaeghen🇩🇪
We present a dispersive amplitude analysis of the low-energy $π^{0} π^{0}$ system in the radiative decay $J / ψ \to γ π^{0} π^{0}$ , using the mass-independent BESIII $0^{++}$ and $2^{++}$ intensities, the total spectrum, and the measured $0^{++} - 2^{++}$ $E 1$ phase difference. The isoscalar $S$ -wave is described by a coupled-channel $π π / K K ˉ$ Muskhelishvili-Omnès representation, which implements the strong final-state interactions associated with the $f_{0} (500)$ and $f_{0} (980)$ . The $D$ -wave is treated with a single-channel $π π$ Muskhelishvili-Omnès representation, where we identify all kinematic constraints of helicity amplitudes before transforming them to the experimental $E 1$ , $M 2$ , and $E 3$ multipoles. Smooth short-distance production of a pseudoscalar-meson pair is encoded in subtraction polynomials, while left-hand-cut effects are estimated and found to be numerically subleading. We identify the negative solution of the BESIII $0^{++} - 2^{++}$ $E 1$ phase ambiguity, after using the modulo- $π$ freedom of production amplitudes, as the phase solution compatible with unitarity constraints, showing that the measured phase information can be accommodated with the Omnès phase motion without requiring large additional phases. By normalizing the BESIII intensities with the extracted branching fraction, we fix the absolute scale of the fitted amplitudes, making them suitable as input for future dispersive studies of two-pion contributions to gravitational form factors.
Comments:
28 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2606.09768 [pdf]
1 citation

Affiliations

first authorsco-authorsvia INSPIRE