Nuclear Theory·nucl-th

Tuesday·June 23, 2026

31 papers—16 primary·15 cross-listed

01
[Submitted on 19 Jun 2026]
Ab Initio Nuclear Theory for Heavy Nuclei and Its Application to Dark Matter-Nucleus Scattering
Bai-Shan Hu🇨🇳
The era of precision ab initio nuclear theory has arrived, enabling uncertainty-quantified predictions for nuclear structure and for interactions with external probes directly from the underlying nuclear force and electroweak currents. This review highlights recent breakthroughs that extend ab initio calculations to the heavy nucleus $^{208}$ Pb, to medium-mass systems with complex deformation, and to weakly-bound nuclei near the driplines. We also summarize ab initio calculations of nuclear responses for dark matter direct detection. Together, these advances demonstrate how ab initio methods can substantially reduce nuclear-physics uncertainties in searches for physics beyond the Standard Model, providing a more robust interpretation of current and forthcoming precision experiments.
Comments:
Accepted by Frontiers in Physics
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.21032 [pdf]
Front.in Phys.(2026)·0 citations
02
[Submitted on 19 Jun 2026]
Level rearrangement in K- p system
T. Massimino🇺🇸 · N.V. Shevchenko🇨🇿 · Z. Papp🇺🇸 · J. Revai🇭🇺
We studied the level shifts in the $K^{-} p$ system caused by the interplay of strong nuclear and long range Coulomb potentials. We observed a level rearrangement in the system and found that the $1 s$ shift of kaonic hydrogen is in fact ``attractive''. In addition, we demonstrated that absorption in the strong antikaon-nucleon interaction does not destroy the level rearrangement.
Comments:
11 pages, 3 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.21261 [pdf]
0 citations
03
[Submitted on 19 Jun 2026]
Is the coexistence of strange quark stars and hadronic stars favored by astrophysical data? A Bayesian analysis
Luca Passarella🇮🇹 · Mirco Guerrini🇮🇹 · Giuseppe Pagliara🇮🇹 · Andrea Lavagno🇮🇹 · Alessandro Drago🇮🇹
Hadronic stars and strange quark stars could coexist within the so-called two-families scenario. In this respect, hadronic matter and strange quark matter correspond to two distinct equilibrium phases described by two different equations of state. We perform here the first detailed Bayesian analysis that makes use of astrophysical and laboratory data in order to constrain the equations of state adopted within the two-families scenario for hadronic and strange quark matter. In particular, in hadronic matter we consider the possible formation of hyperons and delta resonances (beside nucleons) within a class of non linear relativistic mean field models and in quark matter we consider the possible formation of a color-superconducting phase within a bag-like model. Results of the analysis indicate that while at the moment both the one-family and the two-families scenarios are compatible with the data, by comparing the Bayes factors of both models, the two-families scenario is favored with respect to the one-family scenario. Specifically, the two-families framework naturally relieves the tension between the intermediate-density softness of the equation of state required by small-radius objects and the high-density stiffness needed to support massive pulsars. Ultimately, future detections of even more massive compact objects, very compact ordinary-mass objects, or precise measurements of two distinct masses with the same radius, will provide strong indications in favor of the two-families scenario.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2606.21435 [pdf]
JHEAp(2027)·1 citation
04
[Submitted on 19 Jun 2026]
Microscopic mechanism of the Fayans pairing for the enhancement of charge radii
Tomoya Naito · Gianluca Colò · Xavier Roca-Maza · Hiroyuki Sagawa · Enrico Vigezzi
The Fayans energy density functional (EDF), and in particular its pairing sector, have been claimed to be able to reproduce the experimental data of charge radii in many instances. A particularly intriguing case is that of the $Ca$ isotopes between $A = 40$ and $48$ , where charge radii exhibit a "bell shape". In our work, we examine the microscopic origin of this behaviour. We prepare in total $25$ paramerizations of the Fayans-like pairing interaction, that are equivalent in fulfilling the same criteria for the reproduction of empirical pairing gaps. We find that both the density and the density-gradient dependence of the pairing interaction are important to reproduce the well-known enhancement of charge radii in the open-shell nuclei, leading to the "bell shape" behaviour of $Ca$ isotopes. In particular, this originates from the repulsive nature of the rearrangement potential, and cannot simply be mocked up by a refit of the pairing strength. At the same time, we notice some drawbacks of the Fayans standard EDFs, that may call for investigating a more general form of it.
Comments:
22 pages, 28 figures, 6 tables
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.21491 [pdf]
0 citations
05
[Submitted on 19 Jun 2026]
A short-range effective theory for single-neutron halo nuclei with a deformed core
Live-Palm Kubushishi · Daniel R. Phillips
We establish a short-range effective theory for deformed s-wave halos. The theory applies to a system in which neutrons are weakly bound to a core nucleus, and that core nucleus also exhibits a low-lying rotational band with a $0^{+}$ ground state and a first $2_{1}^{+}$ excited state. The effective theory then must have both halo degrees of freedom and degrees of freedom associated with rotation of the core. This leads to the particle plus rotor model of Bohr and Mottelson at leading order. We identify the relevant leading-order operators in the Hamiltonian that respect the symmetries of the system and the small parameters which define the effective theory's power counting. We carry out calculations for the $^{11}$ Be and $^{17}$ C systems in which we compute the low-lying positive-parity states of the core $+$ neutron systems up to the core $(2_{1}^{+})$ -neutron threshold. We do this for several different regulator parameters and establish that these energies can be renormalized using the leading-order set of operators. The spectrum is accurately described at leading order in both cases. Decay widths to d-wave core-neutron states have sizable cutoff dependence, but the Asymptotic Normalization Coefficients (ANCs) in $s$ -wave channels exhibit regulator dependence of a size consistent with next-to-leading-order effects. We also compute Coulomb breakup observables and compare with experimental data, finding leading-order results in reasonable agreement with data for both $^{11}$ Be and $^{17}$ C. The addition of one next-to-leading-order operator renders the ANCs of all s-wave states stable with respect to the regulator. It consequently also removes most of the 30\% variation of the leading-order Coulomb dissociation cross section with the regulator.
Comments:
22 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.21547 [pdf]
0 citations
06
[Submitted on 19 Jun 2026]
Electron scattering and the distribution of electric charge and magnetization inside nuclei
Alex Gnech · Lorenzo Andreoli · Graham Chambers-Wall · Garrett King · Saori Pastore
How are the electric and magnetic distributions carried by protons and neutrons arranged inside an atomic nucleus? One of the most reliable ways to answer this question is to scatter electrons from nuclei. Because the electromagnetic interaction is well understood and electron beams can be prepared and detected with high precision, electron scattering acts as a microscope that probes nuclear structure across a wide range of length scales. In this chapter we discuss how electron-nucleus scattering measurements are related to the distribution of the electric charge and magnetization inside nuclei, and what these distributions reveal about nuclear structure. We present this discussion through modern theoretical tools based on ab initio approaches, which describe nuclei as interacting many-body quantum systems, with many-nucleon interactions and electroweak currents derived from first principles.
Comments:
Invited contribution to the Encyclopedia of Nuclear Physics, 13 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.21576 [pdf]
0 citations
07
[Submitted on 19 Jun 2026]
One-Body and Two-Body Density Matrix Elements in a Symplectic Many-Body Basis
Jakub Herko (1 and 2) · Mark A. Caprio (1) ((1) Department of Physics and Astronomy, University of Notre Dame, (2) TRIUMF)
The symplectic no-core configuration interaction (SpNCCI) framework is an ab initio many-body method for nuclear structure which makes use of the approximate symplectic symmetry of nuclei by appropriate choice of many-body basis states. In this paper we derive recurrence relations allowing for calculation of one-body and two-body density matrix elements between the SpNCCI basis states. Availability of these matrix elements allows for integration of the SpNCCI framework with other modern many-body methods and for calculation of matrix elements of any one-body or two-body operator.
Comments:
25 pages, no figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.21598 [pdf]
0 citations
08
[Submitted on 19 Jun 2026]
Hyperonic equation of state for neutron stars: A systematic Bayesian comparison of density-dependent and non-linear relativistic mean-field models
Pedro Sanson🇵🇹 · Tuhin Malik🇵🇹 · Constança Providência🇵🇹
A systematic Bayesian inference study of the equation of state (EOS) of dense matter with strangeness is presented, extending five relativistic mean-field (RMF) models with both constant and density-dependent couplings to include the full baryon octet. The hyperon-nucleon couplings in the scalar channel are varied within ranges informed by hypernuclear data, while vector isoscalar couplings are fixed by the SU(6) symmetry quark model. Observational constraints from NICER (PSR J0030, J0437, J0740) and GW170817, theoretical constraints from chiral effective field theory ( $χ$ EFT) and perturbative QCD (pQCD), and experimental constraints from nuclear saturation properties are imposed simultaneously. We find that the inclusion of hyperons systematically reduces the maximum neutron star mass by $0.05$ - $0.10, M_{⊙}$ across all models while increasing the radius at $1.4, M_{⊙}$ by $0.5$ - $0.8$ km. The speed of sound exhibits a characteristic softening at densities $2$ - $3, ρ_{sat}$ coinciding with hyperon onset. All hyperonic models remain consistent with the $2, M_{⊙}$ constraint. Models with a more flexible isovector channel span a larger proton fraction when only nucleons are included. However, the extra flexibility is visibly suppressed by hyperons, meaning that the average proton distribution is independent of model flexibility when hyperons are included. Less flexible models show comparable or slightly increased proton fractions due to EOS stiffening when hyperons are included. Only a residual number of hyperonic equations of state give rise to a mass-radius curve with a negative slope at low masses. A $1.8, M_{⊙}$ neutron star with a radius larger than or similar to the radius of a $1.2, M_{⊙}$ star would provide strong evidence that the star contains baryonic degrees of freedom beyond nucleons.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
2606.21617 [pdf]
0 citations
09
[Submitted on 20 Jun 2026]
Nucleon Nucleon Potential Using N $3$ LO Chiral Effective Field Theory
Bassam A. Shehadeh
A microscopic description of nucleon-nucleon (NN) and nucleon-nucleus (NA) scattering is developed using chiral effective field theory (chiEFT) at next-to-next-to-next-to-leading order N3LO. The NN interaction is taken from the EGM formulation, which incorporates spectral function regularization Lambda-tilde to control short range components of the two pion exchange force, together with a Gaussian regulator Lambda to ensure convergence of the Lippmann-Schwinger (LS) equation. The regulator parameters (Lambda, Lambda-tilde) = (450, 500), (550, 600), (600, 600) MeV. The resulting chiEFT NN t-matrix is used to construct the first order optical potential, from which Wolfenstein amplitudes and elastic differential cross sections are calculated. The theoretical amplitudes (B) and (C) for pp and pn scattering at 100 and 200 MeV show good overall agreement with experimental data, with the largest discrepancies appearing in the small real component of the spin orbit amplitude. Calculations of p + 16O and p + 40Ca elastic scattering at 100 and 200 MeV reproduce the measured angular distributions with high accuracy, particularly at forward and intermediate angles. These results demonstrate that the EGM chiEFT potential provides a consistent and quantitatively reliable framework for describing NN observables and NA elastic scattering in the 100-200 MeV energy range, while highlighting the need for improved treatment of short range and spin dependent contributions at higher energies.
Comments:
12 pages and 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.22232 [pdf]
0 citations
10
[Submitted on 21 Jun 2026]
Multistage dynamical modeling of heavy-ion collisions
Lipei Du🇺🇸
Relativistic heavy-ion collisions create deconfined QCD matter whose properties must be inferred from final-state observables through dynamical modeling. This contribution discusses recent progress and open issues in multistage simulations, with emphasis on the connection between bulk evolution, conserved charges, strangeness, and heavy flavor. At RHIC Beam Energy Scan energies, the breaking of longitudinal boost invariance makes charge stopping and rapidity-dependent observables essential for constraining the finite-density medium. Strange hadrons are sensitive to the local chemical environment and conserved-charge correlations, while heavy flavor probes microscopic transport and hadronization. Combining these observables within multi-sector inference frameworks provides a path toward more robust constraints on the equation of state and transport properties of QCD matter.
Comments:
6 pages, 1 figure. Invited plenary talk at Strangeness in Quark Matter 2026 (Los Angeles, CA, USA, Mar 22-27, 2026). Contribution to the proceedings
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2606.22315 [pdf]
1 citation
11
[Submitted on 21 Jun 2026]
Full Configuration Interaction Quantum Monte Carlo for Accurate $Ab Initio$ Nuclear Structure Calculations
Rongzhe Hu · Furong Xu · Baishan Hu · Ali Alavi
We introduce novel full configuration interaction quantum Monte Carlo (FCIQMC) as an accurate many-body solver for $ab initio$ nuclear structure calculations. This stochastic approach directly samples the exact wave function in the full configuration space, enabling high-fidelity treatment of high-order many-body correlations in strongly interacting nuclear systems. Using interactions from chiral effective field theory, we have computed ground-state energies and charge radii of $^{4}$ He, $^{8}$ Be, $^{12}$ C and $^{16}$ O with sub-percent-level many-body uncertainties. These results establish FCIQMC as a stochastic full-configuration-space solver capable of treating systems beyond the reach of the conventional no-core shell model, and as an accurate benchmark for truncated many-body expansion methods.
Comments:
4 pages, 3 figures; comments are welcome
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.22341 [pdf]
1 citation
12
[Submitted on 21 Jun 2026]
Event-by-event fluctuations of elliptic flow in ultrarelativistic O+O collisions
Renata Krupczak🇩🇪 · Nicolas Borghini🇩🇪 · Hendrik Roch🇫🇮
We study O+O collisions at $s_{NN} = 5.36$ TeV within a fully three-dimensional $McDipper$ + $MUSIC$ model, which allows us to describe the experimentally measured dependence of charged hadron multiplicity on centrality and pseudorapidity. We show that the initial elliptical eccentricity is mainly driven by the fluctuations of the energy deposition and thereby varies considerably event-by-event within a fixed centrality class. This also holds for elliptic flow $v_{2}$ , whose origin in O+O thus differs from that in collisions of heavy nuclei. Using a decomposition of initial states in an average event and uncorrelated modes, we find that despite the large size of fluctuations we can reproduce the joint probability distribution of eccentricity and elliptic flow with a reasonable accuracy with only a small set of fluctuation modes.
Comments:
14 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2606.22558 [pdf]
0 citations
13
[Submitted on 22 Jun 2026]
Input-driven analysis in predicting nuclear charge radii using Monte Carlo dropout Bayesian neural network
Jia-Xin Liu · Zhen-Yan Xian · Yan Ya · Si-Ying Ma · Na Tang · Rong An
Nuclei charge radii play an essential role in understanding the fundamental interactions of finite quantum fermion systems. In this work, input-driven Bayesian neural network based on the Monte Carlo dropout approach has been built to characterize the systematic evolution of charge radii of nuclei with proton number $Z \geq 20$ and mass number $A \geq 40$ . The motivated underlying mechanisms have been introduced into the input structures, which contain pairing effect, isospin asymmetry degree, the correlations between the valence nucleons and valence holes for neutron and proton, quadrupole deformation parameter $β_{20}$ , and the local shape staggering phenomena of $^{181, 183, 185}$ Hg isotopes.In addition, shell quenching effect is also taken into account by incorporating the modified Casten factor $P^{*}$ into the input structure. The quadrupole deformation parameters $β_{20}$ derived from finite-range droplet model (FRDM), relativistic mean field (RMF) theory and Weizsäcker-Skyrme (WS) approach are employed to analyze the local variations of nuclear charge radii.The hyperparameter is adjusted automatically in the constructed model.The calibrated results give comparable root-mean-square deviations (RMSD) in the training and validation sets with various shape deformation inputs. The abrupt increase in charge radii around N=60 is well reproduced along Z=37-40 isotopic chains, but this trend is less pronounced along Z=36 and 41 chains. This provides a indicator to confirm the rapid shape-phase transition regions around N=60 from the perspective of finite nuclei size. Shell quenching effect of charge radii along the bismuth isotopes are reproduced well at N=126, but slight deviations can be encountered due to the absence of high-order octupole deformation around N=130 regions and shape-staggering phenomena toward neutron-deficient regions, respectively. This means that...
Comments:
28 pages, 5 figures, accepted by Nuclear Science and Techniques
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2606.22937 [pdf]
0 citations
14
[Submitted on 22 Jun 2026]
Exploring Pion-Induced High-Momentum Components in Nuclei via $(p, p^{'} π)$ Reactions
Junki Tanaka · Junichi Kato · Hiroshi Toki
Pion exchange plays a fundamental role in nuclear structure and is responsible for tensor correlations and high-momentum components in nuclei. The $(p, p^{'} π)$ reaction provides a unique opportunity to investigate pion dynamics under large-momentum-transfer conditions. Its three-body kinematics allows large momentum transfer to be achieved while keeping the excitation energy of the residual nucleus low. We investigate the kinematical properties of the $^{12} C (p, p^{'} π^{+})^{12} B$ reaction using Lorentz-invariant three-body phase-space calculations. The calculations were performed for a 392-MeV proton beam assuming a constant transition amplitude. The resulting momentum-transfer map and phase-space distribution identify experimentally accessible regions of large momentum transfer and provide guidance for optimizing a double-arm spectrometer experiment at RCNP. The present study establishes a model-independent kinematical foundation for future investigations of pion-induced correlations, high-momentum components, and pion dynamics in nuclei.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2606.23067 [pdf]
0 citations
15
[Submitted on 22 Jun 2026]
Scattering Observables from Few-Body Densities and Application in Light Nuclei
Alexander Long
The Transition Density Amplitude (TDA) method of Griesshammer et al. is applied to compute scattering observables for Compton scattering, threshold neutral pion photoproduction, and elastic pion scattering on the light nuclei Hydrogen 3, Helium 3, Helium 4, and Lithium 6. In this formalism the amplitude factorizes into an irreducible few-body kernel, which encodes the interaction of the probe with the active nucleons, and a transition density amplitude, which carries the nuclear structure information. Because the densities are computed once per nucleus and momentum transfer and then convolved with any process-specific kernel, the same nuclear input is reused across reactions, yielding substantial computational savings over direct evaluation. This factorization is realized in the publicly available Fortran suite DensityScattering, developed as part of the present work; a researcher implementing a new reaction need only supply the corresponding kernel in a prescribed format, with infrastructure for density handling, integration, quantum-number summation, and output already provided. The TDAs are constructed from nuclear wave functions using the semilocal momentum-space regularized chiral potential of Reinert, Krebs, and Epelbaum at cutoffs of 450 and 500 MeV. For Lithium 6, no-core shell model wave functions are evolved under a Similarity Renormalization Group (SRG) transformation; a back-transformation scheme ("SRG-And-Back"), co-developed for the present work, returns the densities to the physical momentum scale and thereby preserves the original chiral ordering. The induced uncertainty is validated against exact Helium 4 results at the 2% level, and convergence studies for Lithium 6 Compton scattering bound the residual uncertainty below 6%.
Comments:
Dissertation directed by Harald W. Griesshammer
Subjects:
Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:
2606.23331 [pdf]
0 citations
16
[Submitted on 22 Jun 2026]
Ultra-Peripheral Collisions as a Nuclear-Structure Interferometer with Interpretable Multitask Deep Learning
Jing-Zong Zhang🇨🇳 · Wang-Mei Zha🇨🇳 · Lingxiao Wang🇯🇵 · Guo-Liang Ma🇨🇳
Precise knowledge of nuclear structure is essential across fundamental physics, yet probing these structures is notoriously difficult. To address this challenge, ultra-peripheral collisions (UPCs) provide a femtoscopic tomography for imaging the atomic nucleus. UPCs offer a pristine electromagnetic pathway: coherent vector-meson photoproduction generates patterns of diffraction and two-source interference that directly encode the nuclear spatial density. Turning these patterns into quantitative constraints is, however, a challenging inverse problem, complicated by correlated sensitivities to deformation and neutron skin, phase smearing, and experimental backgrounds. Here we introduce an interpretable Multitask deep-learning framework that maps transverse momentum distributions to multiple nuclear-structure indicators simultaneously and identifies the kinematic regions driving each inference. We demonstrate the approach with coherent $J / ψ$ photoproduction in $_{40}^{96} Zr +_{40}^{96} Zr$ collisions, showing that the learned features separate diffraction-dominated and interference-dominated information and provide analysis-ready observables for future high-luminosity data.
Comments:
14 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); Machine Learning (cs.LG); Nuclear Experiment (nucl-ex); physics.optics (physics.optics); Quantum Physics (quant-ph)
arXiv:
2606.23353 [pdf]
0 citations
17
[Submitted on 13 Aug 2024] (cross-list from astro-ph.HE)
UHECR Clustering: Lightest Nuclei from Local Sheet Galaxies
Daniele Fargion🇮🇹 · Pier Giorgio De Sanctis Lucentini🇷🇺 · Maxim Yu. Khlopov🇷🇺
The ultra-high-energy cosmic ray (UHECR) puzzle is reviewed under the hints of a few basic results: clustering, anisotropy, asymmetry, bending, and composition changes with energies. We show how the lightest UHECR nuclei from the nearest AGN or Star-Burst sources, located inside a few Mpc Local Sheets, may explain, at best, the observed clustering of Hot Spots at tens EeV energy. Among the possible local extragalactic candidate sources, we derived the main contribution of very few galactic sources. These are located in the Local Sheet plane within a distance of a few Mpc, ejecting UHECR at a few tens of EeV energy. UHECR also shine at lower energies of several EeV, partially feeding the Auger dipole by LMC and possibly a few nearer galactic sources. For the very recent highest energy UHECR event, if a nucleon, it may be explained by a model based on the scattering of UHE ZeV neutrinos on low-mass relic neutrinos. Such scatterings are capable of correlating, via Z boson resonance, the most distant cosmic sources above the GZK bound with such an enigmatic UHECR event. Otherwise, these extreme events, if made by the heaviest composition, could originate from the largest bending trajectory of heaviest nuclei or from nearby sources, even galactic ones. In summary, the present lightest to heavy nuclei model UHECR from the Local Sheet could successfully correlate UHECR clustering with the nearest galaxies and AGN. Heavy UHECR may shine by being widely deflected from the Local Sheet or from past galactic, GRB, or SGR explosive ejection.
Comments:
26 pages. 10 figures, Universe Journal, https://doi.org/10.3390/universe10080323
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2408.07172 [pdf]
Universe(2024)·8 citations
18
[Submitted on 18 Jun 2026] (cross-list from hep-lat)
Neural Wavefunctions in Quantum Field Theory I: Asymptotic Freedom
Paulo F. Bedaque🇺🇸 · Hersh Kumar🇺🇸 · Suryansh Rajawat🇺🇸 · Gregory Ridgway🇺🇸
We present a variational approach to quantum field theory based on wavefunctions parameterized by neural networks. While variational methods have a celebrated history across many fields, their application to quantum field theory has been limited by well-known challenges. We show that neural-network wavefunctions, combined with modern machine-learning techniques, enable competitive variational calculations in nontrivial field theories. As a demonstration, we reproduce the essential features of the two-dimensional nonlinear $σ$ -model: asymptotic freedom, dynamical mass generation and the model's step-scaling function.
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2606.20791 [pdf]
0 citations
19
[Submitted on 18 Jun 2026] (cross-list from hep-ph)
Event-Level QCD Inference Framework for Quark-Gluon Imaging
Patrick Barry🇺🇸 · Pi-Yueh Chuang🇺🇸 · Ian Cloët🇺🇸 · Emil Constantinescu🇺🇸 · Arkaprabha Ganguli🇺🇸 · Chao Peng🇺🇸
We introduce and demonstrate an event-level analysis framework for quark-gluon imaging. For a first application we use it for the inference of parton distribution functions from synthetic deep inelastic scattering data. This framework removes the need for unfolding of detector effects and the binning of events, and therefore eliminates two key sources of information loss. We contrast this event-level framework with the traditional histogram approach by performing a closure test for parton distribution functions from event data obtained from a known ground truth. In this study we assume a perfect detector, which makes unfolding straightforward. The elimination of binning in the event-level framework is demonstrated to have important benefits over the traditional histogram approach, and performs better in the closure test, particularly for a smaller number of events. For example, defining a mean-squared error distance metric, we find that the event-level framework performs around $35%$ better than the traditional approach for a moderate number of events. The benefits of an event-level framework should increase for inference associated with 3D quark-gluon imaging, because these differential cross sections are of higher dimension and the comparative number of measured events is significantly reduced.
Comments:
8 pages, 4 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2606.20923 [pdf]
0 citations
20
[Submitted on 18 Jun 2026] (cross-list from hep-ph)
Gluon GTMD at strong coupling: fixed-spin saddle factorization and Reggeization
Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
Generalized transverse-momentum-dependent parton distributions (GTMDs) are the most complete two-parton correlation functions in QCD, encoding the joint spatial and momentum structure of hadrons. Through appropriate projections and limits they yield generalized parton distributions (GPDs), transverse-momentum-dependent distributions (TMDs), parton distribution functions (PDFs), and phase-space (Wigner) distributions. We construct conformal moments of unpolarized gluon GTMDs at strong coupling using gauge/string duality. For fixed even conformal spin $j$ , we distinguish the local boundary limit at $b_{T} = 0$ from the finite-separation regime $b_{T} > 0$ , where the planar semiclassical amplitude is governed by a minimal worldsheet. There the GTMD moment factorizes into a universal staple-worldsheet soft factor and a stripped spin- $j$ Witten amplitude carrying target dependence. The cusp of the renormalized minimal area generates the rapidity-logarithmic Collins-Soper structure. We derive universal ultraviolet and infrared endpoint reductions. As $b_{T} \to 0^{+}$ , the finite-separation sector matches onto the local conformal moment through a universal overlap kernel. At large $b_{T}$ , after cusp/perimeter subtraction, it factorizes into target projections and infrared transfer kernels. The ultraviolet endpoint is universal within the leading saddle, whereas the infrared tail depends on the holographic completion: soft-wall, gap-matched hard-wall, and repulsive-wall backgrounds generate algebraic, exponential, and Gaussian falloffs, respectively. Analytic continuation in $j$ yields the low- $x$ Regge regime governed by the holographic Pomeron spectral curve. The framework describes hadron tomography, transverse structure, rapidity evolution, and Reggeization for GTMD moments and provides a unified starting point for holographic studies of observables relevant to the Electron-Ion Collider.
Comments:
34 pages, 3 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.20981 [pdf]
0 citations
21
[Submitted on 19 Jun 2026] (cross-list from hep-ph)
Pion structure from its light-front wave function
Khépani Raya · Zhen-Ni Xu · Zhao-Qian Yao · José Rodríguez-Quintero
Understanding the structural properties of the pion is essential for elucidating the mechanisms of mass generation within the Standard Model and their role in the emergence and properties of the hadronic matter. Light-front wave functions encode extensive information about the internal structure of these systems and provide the link to measurable quantities such as generalized parton distributions and transverse-momentum-dependent distributions. Guided by recent progress in continuum Schwinger methods, we derive well-founded and practical representations of these quantities, enabling the exploration of several facets of the pion structure, including distribution amplitudes and distribution functions, elastic and gravitational form factors, and the associated momentum and spatial distributions. The results presented here are consistent with expectations and can be tested at modern experimental facilities, including the new generation of electron-ion colliders.
Comments:
11 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.20998 [pdf]
1 citation
22
[Submitted on 19 Jun 2026] (cross-list from nucl-ex)
Evidence of the Excited X(5)-like Critical-Point Symmetry Structures in 152Sm
S. Basak🇮🇳 · S. Rajbanshi🇮🇳 · T. Bhattacharjee🇮🇳 · D. Kumar🇮🇳 · A. Pal🇮🇳 · S. S. Alam🇮🇳 · A. Saha🇮🇳 · A. K. Sikdar🇮🇳 · J. Nandi🇮🇳 · Ananya Das🇮🇳 · Shabir Dar🇸🇪 · S. Samanta and 14 other authors
The positive-parity structure of 152Sm has been investigated through high-statistics {\gamma}-ray spectroscopy following the (150Nd({\alpha},2n)152Sm reaction at Elab = 26 MeV. Several collective structures built on excited 0+ states have been extended through the observation of new levels and {\gamma}-ray transitions, and spin-parity assignments have been established using directional-correlation and linear-polarization measurements. Electromagnetic transition strengths (B(E2)), deduced from measured branching ratios and known level lifetimes, reveal pronounced collectivity among the excited configurations. The resulting level scheme provides evidence for a sequence of excited collective bands extending beyond the well-known ground-state and first excited 0+ structures. The excitation energies and transition strengths are examined within the framework of the X(5) critical-point description of the first-order U(5)-SU(3) shape-phase transition. In addition to the established X(5)-like features of the low-lying spectrum, the observed systematics of the higher-lying bands are found to be consistent with excited collective structures exhibiting X(5)-like characteristics. The results provide new constraints on the realization of critical-point behavior in finite nuclei and on the evolution of collectivity in the N=90 region.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.21269 [pdf]
PLB(2026)·0 citations
23
[Submitted on 19 Jun 2026] (cross-list from astro-ph.HE)
A New Scaling of Neutron Star Tidal Deformability for Directly Probing the Core Equation of State
Jian-Hao Shi🇨🇳 · Bao-Jun Cai🇨🇳 · Bao-An Li🇺🇸 · Yu-Gang Ma🇨🇳
The dimensionless tidal deformability, $Λ$ , of neutron stars (NSs), inferred from gravitational-wave (GW) observations, has thus far been used primarily to constrain the pressure of dense matter near twice nuclear saturation density, leaving the core equation of state (EOS) largely inaccessible to inspiral-phase GW observations. We show that the core EOS can be probed directly through $Λ$ using a perturbative analysis of the dimensionless stellar-structure and tidal-response equations formulated in terms of scaled intrinsic variables, without invoking any specific EOS model. We uncover a remarkable EOS-insensitive scaling relation between $Λ$ and the central EOS parameter $X \equiv P_{c} / ε_{c}$ , where $P_{c}$ and $ε_{c}$ denote the central pressure and energy density, respectively. The relation is validated against a broad ensemble of physically viable EOSs. Applying it to tidal deformabilities inferred from events such as GW170817 enables a direct determination of $X$ . We further derive a tight lower bound, $Λ_{TOV} ≳ 9. 2_{- 1.2}^{+ 1.2}$ , for maximum-mass NSs along stable mass-radius sequences, quantitatively demonstrating that even the most compact stable NSs remain distinctly separated from black holes, for which $Λ_{BH} = 0$ . These findings reveal a previously unrecognized connection between inspiral-phase tidal deformability and the core EOS, establishing a direct link between GW observables and the microphysics of ultradense matter in the strong-gravity regime. The resulting scaling establishes inspiral-phase tidal deformability as a direct and largely model-insensitive probe of the EOS of NS cores.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.21402 [pdf]
2 citations
24
[Submitted on 19 Jun 2026] (cross-list from hep-ph)
The shear viscosity of quark-gluon matter calculated with parton transport and comparisons with the Chapman-Enskog results
Mason Alexander Ross🇺🇸 · Zi-Wei Lin🇺🇸
We numerically calculate the shear viscosity of quark-gluon matter via the Green-Kubo relation with an improved ZPC model. We include all $2 \leftrightarrow 2$ parton cross sections at finite temperature, which are based on perturbative QCD and screened with thermal masses, and consider massless quark-gluon systems with Boltzmann statistics in chemical equilibrium. We then compare the Green-Kubo results with the analytical results from the leading-order Chapman-Enskog method for the same parton cross sections over the temperature range $150 - 600$ MeV. We also examine the simpler case of isotropic and constant parton cross sections. Overall, we find that the two methods agree rather well. Specifically, the Green-Kubo results are greater than the Chapman-Enskog results by an average of $\sim 9%$ for isotropic and constant cross sections and by an average of $\sim 3%$ for finite-temperature pQCD cross sections, where the difference between the two methods is presumably due to higher-order corrections to the leading-order Chapman-Enskog results.
Comments:
19 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.21722 [pdf]
1 citation
25
[Submitted on 20 Jun 2026] (cross-list from hep-lat)
Proton's isovector PDF with updated analysis of large-momentum lattice data
Xiangdong Ji🇨🇳 · Yushan Su🇺🇸
The proton's unpolarized $u (x) - d (x)$ parton distribution function (PDF) has been studied by a number of lattice QCD groups through large momentum expansion. However, due to lattice artifacts (excited state contaminations, unphysical pion masses, and discretization effects) and less-advanced theoretical analysis (renormalizations, large-distance extrapolations, and large-log resummations), the resulting PDFs cannot be compared strictly with experimental data. By using the state-of-the-art theoretical tools and mitigating the lattice artifacts empirically, we reanalyze the available datasets in the literature and find that the new PDF in the physical limits is consistent with global fittings within $\sim 1 σ$ . This provides compelling evidence that large momentum expansion is capable of accurately predicting the $x$ -dependence of the PDFs when ideal lattice data become available.
Comments:
6 pages, 2 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.22224 [pdf]
0 citations
26
[Submitted on 21 Jun 2026] (cross-list from hep-ph)
Quantum Simulation of Generalized Parton Distributions in the Schwinger Model
Tianyin Li🇯🇵 · Hongxi Xing🇨🇳
We present a quantum algorithm for simulating Generalized Parton Distributions (GPDs) in the Schwinger model. Unlike the staggered fermions widely utilized in current quantum simulations, we employ Wilson fermions for lattice discretization. This choice is critical for the quantum computation of GPDs due to their strict preservation of charge conjugation symmetry. We construct a comprehensive algorithmic framework that includes the preparation of hadronic states with non-zero momentum and the measurement of light-cone correlation functions incorporating Wilson lines. We provide a complexity analysis, demonstrating that the resources required for our algorithm scale polynomially with both the number of qubits and the desired precision $ε$ . Finally, we benchmark our approach using exact diagonalization, extracting mass spectra and GPDs (also parton distribution functions) that are consistent with theoretical expectations and fundamental physical constraints.
Comments:
9 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2606.22602 [pdf]
0 citations
27
[Submitted on 22 Jun 2026] (cross-list from hep-th)
Quantized Irreversible Null-geometry: Foundation and Applications
Si-xue Qin🇨🇳
Formulating a consistent integration measure for quantum geometric fluctuations without violating diffeomorphism invariance remains a theoretical challenge. In this work, a framework rooted in the statistics of discrete Poisson point processes is proposed. The formulation yields a double-exponential probability functional characterized by a capacity limit, which acts as an amplitude regularizer suppressing ultraviolet singularities. To evaluate this model at macroscopic scales, a statistical bifurcation of the stochastic action is identified. First, the macroscopic mean condenses to define the classical continuous spacetime background and its matter distribution. Second, at macroscopic scales, the Law of Large Numbers dictates that the residual ultraviolet noise maps into an infrared continuous zero-mean Gaussian martingale within the bulk. Third, this zero-mean Gaussian noise linearly generates standard quantum kinematic effects. Fourth, evaluating the non-linear exponential action separates the variance of this Gaussian noise from the linear cancellation, rectifying it into a macroscopic drift that manifests as the dark energy density. Diluted by the Bekenstein-Hawking entropy of the observable universe, this bulk variance dictates a continuous field cutoff at 6 TeV. Building upon this framework, broad phenomenological applications are demonstrated: (1) establishing a UV-finite effective field theory preserving gauge symmetries in 4D; (2) constructing a topological model of particles deriving Standard Model hierarchies; (3) formulating a non-singular cosmological model predicting observed large-scale power suppression in the cosmic microwave background; and (4) deriving foundational axioms of quantum mechanics as emergent statistical phenomenologies. Collectively, this framework provides a falsifiable synthesis bridging discrete quantum geometry and continuous macroscopic physics.
Comments:
v2 is a comprehensive, standalone monograph that heavily generalizes our framework, integrating the full theoretical foundation and multi-domain phenomenological solutions into a unified 80-page study. Supersedes and consolidates our preliminary related developments
Subjects:
High Energy Physics — Theory (hep-th); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2606.22788 [pdf]
0 citations
28
[Submitted on 22 Jun 2026] (cross-list from hep-ph)
A novel approach for studying two-particle momentum correlation function in relativistic nuclear collisions
Zhi-Lei She🇨🇳 · Wen-Chao Zhang🇨🇳 · An-Ke Lei🇨🇳 · Dai-Mei Zhou🇨🇳 · Hua Zheng🇨🇳 · Li-Lin Zhu🇨🇳 · Qiang Wang🇨🇳 · Yu-Liang Yan🇨🇳 · Zhong-Qi Wang🇨🇳 · Ben-Hao Sa🇨🇳
Two particle momentum correlation functions provide a nontrivial tool for probing the strong interaction and/or extracting particle emission source information in relativistic nuclear collisions. Although transport models can describe the microscopic phase-space evolution of the collision system, calculating correlation functions within the framework of transport models remains challenging. In this paper, we employ the mixed-event technique to calculate two particle momentum correlation function as $C (k^{*}) = N ξ (k^{*}) \frac{N _{same} ( k ^{*} )}{N _{mixed} ( k ^{*} )}$ based on the parton and hadron cascade model PACIAE simulated final hadronic state (FHS) with introducing a modification factor $ξ (k^{*})$ to improve the treatment of final-state interactions and quantum statistics effects in the PACIAE model. The simulated results show good agreement with the ALICE data for $K p$ , $pp$ , $p Λ$ , and $ΛΛ$ momentum correlation functions in $pp$ collisions at $s = 7$ TeV. On the other hand, the particle emission source radius of the correlated pairs are also evaluated based on the simulated FHS self-consistently. Since the PACIAE model employs hadron-hadron cross sections derived from the additive quark model, the calculation of two-particle momentum correlation functions does not require prior assumptions about the interaction between the two correlated particles. This successful ``PACIAE + modification factor" approach may shed light on the future study of momentum correlation functions for dimesons, dibaryons, and even diexotic hadrons.
Comments:
4 pages,1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.22865 [pdf]
0 citations
29
[Submitted on 22 Jun 2026] (cross-list from astro-ph.HE)
Neutron Star Mass-Radius Constraints for EXO 0748 $-$ 676 from 2008-2025 Quiescent X-ray Spectra
Mingyang Wang · Guobao Zhang · Ang Li
We present new constraints on the mass and radius of the neutron star in the neutron star low-mass X-ray binary EXO 0748 $-$ 676 obtained from a joint analysis of 20 quiescent X-ray observations obtained between 2008 and 2025, including 14 Chandra and 6 XMM-Newton exposures. These data sample two quiescent episodes separated by the 2024 $-$ 2025 outburst. We model the 0.5 $-$ 10 keV spectra with a hydrogen-atmosphere model, assuming a source distance of 7.1 kpc. In a global Markov Chain Monte Carlo analysis in which the hydrogen column density, neutron star mass, and radius are tied across all observations, we obtain a neutron-star mass of $1.7 7_{- 0.22}^{+ 0.17} M_{⊙}$ and a radius of $12.6 2_{- 0.74}^{+ 0.56}$ km ( $1 σ$ credible intervals). We further perform independent fits to the first and second quiescent epochs and find that the combined data set significantly reduces the low-mass tail in the posterior distribution, leading to tighter lower bounds on the neutron-star mass. Incorporating the distance uncertainty of $7.1 \pm 1.2$ kpc, we conservatively constrain the neutron-star mass and radius to $M ≃ 1.41 - 2.11 M_{⊙}$ and $R ≃ 10.15 - 15.13$ km, favoring relatively stiff dense-matter equations of state. We also trace the thermal evolution across two quiescent epochs and find evidence for renewed crust cooling following the 2024 $-$ 2025 outburst, providing a unique opportunity to compare the thermal relaxation behavior after two distinct accretion episodes.
Comments:
11 pages, 4 figures, 3 tables; Comments welcome
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2606.23466 [pdf]
0 citations
30
[Submitted on 22 Jun 2026] (cross-list from hep-ph)
Irrelevance of Anomalous Breaking of Axial U(1) Symmetry and the U(1) Problem
Nodoka Yamanaka🇯🇵
The eta and eta' mesons are conventionally known to receive contribution from the anomalous breaking of axial U(1) symmetry, and they are considered to not be the Nambu-Goldstone (NG) bosons of the spontaneous chiral SU(3)_L x SU(3)_R symmetry breaking of QCD. However, it has recently been shown that this axial U(1) anomaly is not actually physical. In this contribution, we first review this statement and then propose a mechanism in which eta and eta' mesons are indeed NG bosons while being consistent with the axial U(1) problem.
Comments:
6 pages, 3 figures, proceedings of the 15th International Conference on Hypernuclear and Strange Particle Physics (HYP2025), University of Toyko, Japan, October 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2606.23578 [pdf]
0 citations
31
[Submitted on 22 Jun 2026] (cross-list from hep-ph)
Quantification of the Flavor Diagonal Hadronic CP Violation
Nodoka Yamanaka🇯🇵
The flavor diagonal CP violation of elementary particle physics contributes to the atomic, nuclear, and nucleon electric dipole moments (EDMs), T-violating neutron optics, and to the angular correlations of beta decay. In this contribution, we review the basics and the importance of CP violation in the search for new physics beyond the standard model, the recent progress in the quantification of the hadron level CP violation contributing to the aforementioned observables, and finally the current attempt to solve the strong CP problem without additional interactions and fields.
Comments:
8 pages, 1 figure, proceedings of the 9th International Symposium on Symmetries in Subatomic Physics (SSP2025), Nara, Japan, September 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.23580 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE