Nuclear Theory·nucl-th

Tuesday·June 9, 2026

30 papers—13 primary·17 cross-listed

14
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.
↳ hep-phnucl-th2 citations
15
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.
↳ nucl-exnucl-th1 citation
16
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 $a_{2}$ .
↳ hep-phnucl-th1 citation
17
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.
↳ hep-phcond-mat.stat-mechhep-thnucl-th+10 citations
18
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.
↳ hep-phhep-thnucl-th1 citation
19
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.
↳ hep-phnucl-th0 citations
20
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.
↳ hep-phnucl-th0 citations
21
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.
↳ cond-mat.stat-mechnucl-thquant-ph0 citations
22
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.
↳ hep-phnucl-th1 citation
23
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.
↳ astro-ph.HEnucl-thAstron.Astrophys.(2026)·0 citations
24
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.
↳ hep-phhep-exhep-latnucl-ex+10 citations
25
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.
↳ hep-phhep-exhep-latnucl-ex+10 citations
26
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.
↳ astro-ph.HEnucl-exnucl-th0 citations
27
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.
↳ hep-phnucl-th0 citations
28
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.
↳ hep-phhep-latnucl-th2 citations
29
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.
↳ hep-phhep-thnucl-th1 citation
30
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.
↳ hep-phhep-exhep-latnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE