Nuclear Theory·nucl-th

Tuesday·September 1, 2026

17 papers—7 primary·10 cross-listed

08
Machine Learning Unveils Finite-volume Energy Shifts in Three-body System
Wei-Jie Zhang🇨🇳 · Zhenyu Zhang🇨🇳 · Jifeng Hu🇨🇳 · Bing-Nan Lu🇨🇳 · Jin-Yi Pang🇨🇳 · Qian Wang🇨🇳
Finite-volume extrapolation (FVE) is essential for extracting physical observables in the lattice calculation. While rigorous FVE formulations are well established for short-range potentials in both two- and three-body systems, long-range interactions with force ranges comparable to the lattice size $L$ remain challenging. Extending a previous data-driven scheme for two-body systems, we apply symbolic regression (PySR) to uncover universal three-body FVE formulae. For short-range potentials, we reproduce the two limiting cases, i.e. $κ_{3} ≫ κ_{2}$ and $κ_{3} \sim κ_{2}$ . For pure long-range potentials, we obtain a dedicated analytic expression, and after incorporating short-range contributions, we uncover a unified formula consistent with the original PySR solution, which performs excellently in the intermediate force range around 1 fm. This work demonstrates that combining machine learning with physical constraints can yield novel analytical results inaccessible to conventional theoretical tools, advancing data-driven methodologies in hadron physics.
↳ hep-lathep-phnucl-th0 citations
09
Constrained functional priors for Bayesian inference of hot QCD matter
G. Guimarães🇧🇷 · L. Perin🇧🇷 · M. Luzum🇧🇷
Bayesian analyses of heavy-ion collisions rely on functional inputs, such as temperature-dependent transport coefficients and the equation of state, whose prior specification remains a significant source of uncertainty. Standard approaches employ low-dimensional parametrizations that can impose artificial correlations and leave the resulting inference sensitive to the assumed functional form. We develop a nonparametric framework for constructing priors over such functions using Gaussian processes, tailored to emulator-based inference in heavy-ion phenomenology. Truncated Karhunen--Loève expansions yield optimized finite-dimensional representations suitable for use as emulator inputs. We investigate how physical constraints can be incorporated into these priors, demonstrating that rejection-based methods produce non-Gaussian measures and induce nontrivial correlations in the expansion coefficients. By contrast, pushforward constructions enforce the constraints while preserving a tractable Gaussian measure in a latent space. These results provide a systematic framework for incorporating physical constraints into functional priors and clarify their effects on the statistical structure of the finite-dimensional representations used in Bayesian inference.
↳ hep-phnucl-th0 citations
10
On-shell renormalization in NREFT: a simplified description of resonances, bound states, and coupled channel effects
Guo-Ying Chen🇨🇳
We discuss several issues regarding the modern generalization of Weinberg's compositeness criterion. In particular, we demonstrate that the on-shell renormalization in NREFT reproduces Weinberg's result and provides a simple description of resonances, bound states, and coupled channel effects. Additionally, we present the complete propagator, including the charged channel for the near-threshold p-wave states.
↳ hep-phhep-exnucl-th0 citations
11
Two Languages for the Same Resonance: From Nuclear Decay to Black-Hole Ringdown
Okuto Morikawa
Quantum resonances and black-hole quasinormal modes (QNMs) are described by closely related mathematics: radiative boundary conditions, analytic continuation of Green functions or resolvents, poles on nonphysical sheets, and non-self-adjoint spectral representations. This article does not introduce that equivalence but reconstructs its genealogy. Nuclear resonance theory grew from radioactive decay, reaction cross sections, metastable compound states, and complex energies, whereas black-hole perturbation theory grew from spacetime stability and causal response. We place the two developments on a common chronology, from Sommerfeld's radiation condition and early nuclear-decay theory through Regge--Wheeler perturbations, Vishveshwara's 1968 dissertation and 1970 papers, Press's 1971 quasi-normal terminology, and the independent Aguilar--Balslev--Combes theory of analytic dilation, then follow their later mathematical reunification in scattering-resonance theory. Alongside the chronology, we give a working dictionary relating no-incoming and horizon-ingoing/infinity-outgoing conditions, pole energy and complex frequency, width and damping rate, residues and excitation factors, and nonresonant background with branch-cut and prompt contributions. The aim is to make the cross-disciplinary equivalence operational without flattening its history, and to distinguish mathematical equivalence from historical genealogy.
↳ gr-qcmath-phmath.MPnucl-th+10 citations
12
Spin-dependent fermion potentials from mixed tensor couplings of massive spin-1 and spin-2 bosons
D. Khadka🇦🇺 · V.V. Flambaum🇦🇺
Searches for weak spin-dependent forces are commonly interpreted in terms of a basis of sixteen rotationally invariant two-fermion potentials $V_{1 - 16}$ , including potentials which violate parity (P) and time-reversal (T) invariance. We derive finite-range coordinate-space potentials generated by a massive spin-1 boson with vector, axial-vector, tensor, and pseudotensor couplings to Dirac fermions. In addition to the familiar vector--vector, vector--axial-vector, and axial-vector--axial-vector interactions, we obtain the mixed vector--tensor, vector--pseudotensor, axial-vector--tensor, and axial-vector--pseudotensor potentials, together with tensor--tensor, tensor--pseudotensor, and pseudotensor--pseudotensor terms. We retain the contact terms needed in atomic-scale applications and give compact expressions that include both orderings of inequivalent fermion vertices. We then extend the analysis to a massive spin-2 mediator described by a symmetric Fierz--Pauli field. Besides the conventional coupling to the conserved fermion energy--momentum tensor, we consider a symmetric axial-tensor current. Its nonconservation for massive fermions makes the longitudinal spin-2 helicities contribute to axial-tensor--axial-tensor exchange. The leading minimal spin-2 interactions are either $P, T$ even or $P$ odd and $T$ even; in particular, they do not generate a $T$ -odd potential. Heavy-mediator contact limits and the distinction between the $M \to 0$ massive-spin-2 limit and a genuine massless graviton are also discussed. We map the new interactions onto the sixteen-potential Dobrescu--Mocioiu basis and use this mapping to obtain numerical translations of existing limits for both spin-1 and spin-2 coupling products in the small- and large-mediator-mass regimes, together with representative limits at finite mediator masses.
↳ hep-phnucl-thphysics.atom-ph0 citations
13
Meson gravitational D-form factors and symmetry breaking in low-energy QCD
Mamiya Kawaguchi🇺🇸 · Kazuhiro Tanaka🇯🇵 · Mitsuru Tanaka🇯🇵
We investigate meson gravitational D-form factors in the three-flavor linear sigma model and their connection to symmetry breaking in low-energy QCD. Within the scalar meson dominance picture, we examine the scalar meson exchange contributions and their relation to meson masses through scalar-meson couplings. In the three-flavor symmetric limit, we first derive analytical expressions for the D-form factors of pseudoscalar and scalar mesons. In the chiral limit, the forward-limit value of the octet pseudoscalar D-form factor is fixed to $- 1$ , whereas the $U (1)_{A}$ anomaly generates additional contributions to the singlet pseudoscalar and scalar-meson D-form factors. For realistic flavor breaking, the interaction introduced to reproduce the scalar-meson mass hierarchy below $1$ GeV significantly affects the scalar-meson D-form factors. We further compare the linear sigma model results with those obtained from a chiral perturbation theory Lagrangian including a dilatonic scalar field and show that their differences are governed by the canonical mass dimensions of the interaction terms contributing to meson mass generation. These results indicate that meson D-form factors provide sensitive probes of symmetry-breaking structures in low-energy hadron physics.
↳ hep-phhep-latnucl-th0 citations
14
Polarized jet anisotropy at the Electron-Ion Collider
Zhong-Bo Kang🇺🇸 · Hongxi Xing🇨🇳 · Fanyi Zhao🇺🇸 · Yiyu Zhou🇨🇳
Jets provide a powerful probe of the three-dimensional spin structure of the nucleon, a central goal of the Electron-Ion Collider. Yet the observed jet defines an axis that breaks the azimuthal isotropy of soft-gluon radiation, thereby reshaping the very asymmetries used to extract that structure. Using transverse-momentum-dependent (TMD) QCD factorization, we show for the first time that this jet-induced anisotropy imposes a parity selection rule on polarized asymmetries. Expanding the transversely polarized structure functions in harmonics $cos (n ϕ_{q J})$ , where $ϕ_{q J}$ is the angle between the jet and the lepton-jet momentum imbalance, makes this rule explicit: the symmetry of each harmonic is fixed by the parity of $n$ , independently of the magnitudes of the harmonic coefficients. For the Sivers function, the canonical left-right asymmetry about the proton spin survives for even $n$ but is replaced by a counterintuitive left-right symmetry for odd $n$ . The worm-gear function retains its up-down asymmetry at every harmonic while being left-right symmetric for even $n$ and asymmetric for odd $n$ . At EIC kinematics, the higher harmonics studied here are predicted to be individually measurable, providing new observables for the azimuthal dynamics of soft radiation and an essential ingredient in precision extractions of nucleon structure.
↳ hep-phhep-exnucl-th0 citations
15
Exploring possible $_{Λ_{c}}^{3} H$ bound states through $p Λ_{c}$ femtoscopic correlations
Ye Yan🇨🇳 · Qi Huang🇨🇳 · Qian Wu🇨🇳 · Hongxia Huang🇨🇳 · Jialun Ping🇨🇳
The femtoscopic correlation technique in relativistic heavy-ion collisions provides a unique opportunity to investigate hadron-hadron interactions and possible exotic states. In this work, we study the $p Λ_{c}$ correlation function and its sensitivity to the low-energy $N Λ_{c}$ interaction related to possible $_{Λ_{c}}^{3} H$ bound states. Based on the quark delocalization color screening model, three interaction scenarios with different strengths are constructed, and the corresponding spin-averaged $p Λ_{c}$ correlation functions are calculated within the Koonin--Pratt formalism. The results demonstrate that the correlation function is sensitive to the $p Λ_{c}$ interaction strength, with coupled-channel effects and $S$ - $D$ wave mixing producing additional enhancements in the correlation signal. These findings suggest that future $p Λ_{c}$ femtoscopic measurements at relativistic heavy-ion collision experiments can provide valuable constraints on the interaction between charmed baryons and nucleons and offer guidance for exploring possible heavy-flavor hypernuclei.
↳ hep-phnucl-th0 citations
16
Charmonium production in p+A collisions at SPS and FAIR energies
Taesoo Song🇩🇪 · Jiaxing Zhao🇩🇪 · Joerg Aichelin🇫🇷 · Elena Bratkovskaya🇩🇪
We employ the Parton-Hadron-String Dynamics (PHSD) transport approach to investigate the influence of baryon-rich matter on charmonium production and dissociation. The Remler formalism is implemented to dynamically model charmonium formation from charm-anticharm pairs. As a validation step, the formalism is first benchmarked against experimental data from elementary pp collisions and then extended to pA systems to extract the effective nuclear absorption cross section of charmonium. This extracted cross section can subsequently be applied in heavy-ion collisions to quantify medium-induced effects. Our results demonstrate that the Remler formalism provides a quantitatively consistent description of charmonium production in pp and pA collisions at SPS energies. The approach is then extrapolated to GSI/FAIR energies, where predictions for charmonium yields and survival probabilities are presented. These findings highlight the relevance of the Remler formalism as a dynamical framework for studying heavy-quark bound-state formation in baryon-rich matter and offer theoretical guidance for future experimental programs at SPS, FAIR and NICA aimed at mapping the QCD phase structure.
↳ hep-phnucl-th0 citations
17
Small-x TMD distributions: JIMWLK evolution and the Gaussian truncation
Florian Cougoulic🇵🇱 · Piotr Korcyl🇵🇱
We extend the systematic study of small- $x$ Transverse Momentum Dependent (TMD) distributions, initiated in [Cougoulic:2026drr], by including the energy evolution. We use the JIMWLK evolution equation to study the energy dependence of three distributions in the quark-gluon sector, $F_{q g}$ , and seven distributions in the gluon-gluon sector, $F_{g g}$ . The initial conditions are provided by the McLerran-Venugopalan model. We study these TMD distributions in position space and with $N_{c} = 3$ fixed. We then compare these results to the Gaussian truncation of the Balitsky hierarchy. Although the Gaussian truncation worked very well for the TMD distributions at the initial condition, now we identify some cases where the Gaussian truncation provides a reasonably good description, but in the majority of cases it fails to fully reproduce numerical data. Using the fixed representation building blocks, $Ω_{a g}^{ω}$ , we are able to partially explain the outcomes. This work constitutes the next step with the goal of understanding the interplays between the large- $N_{c}$ limit and Gaussian truncation as well as the BK/JIMWLK evolution equations for phenomenologically relevant observables.
↳ hep-phnucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE