Nuclear Theory·nucl-th

Thursday·August 20, 2026

13 papers—5 primary·8 cross-listed

01
Comparison of several model averaging methods in nuclear charge radius predictions
Huan-Yu Zhang · Rui Jing · Zhen-Hua Zhang · Xin-Hui Wu · Zhong-Ming Niu
The performance of five model averaging methods, including the arithmetic mean (AM), weighted mean (WM), naive Bayesian model averaging (NBMA), principal component analysis (PCA), and power-moderated mean (PMM) methods, in nuclear charge radius predictions is investigated. Five commonly used nuclear charge radius models are adopted as inputs for the averaging procedures. The charge radius differences between the experimental data and the original nuclear models are analyzed and the results after considering the model averaging methods are also discussed. The calculations show that the NBMA method can provide the best root-mean-square (rms) deviation among these five model averaging methods. The PCA method can extract useful physical information and not only helps to interpret the model differences but also offers a feasible way to construct improved empirical models by recombining the principal components. In contrast to the other methods, whose results worsen upon including a new model with a larger rms deviation, the rms deviation of the PCA method remains almost unaffected. The PMM method is capable of integrating the strengths of various nuclear models and delivering reasonable uncertainty estimates not only in known regions but also in unknown ones. This method can automatically adjust data uncertainties to achieve consistency, and it can provide a tool for a smooth transition of the nuclear charge radius prediction from the WM to the AM. The extrapolation ability of these model averaging methods is checked by 66 newly observed data after year 2021. The calculations show that model averaging offers a reliable strategy for nuclear charge radius predictions, combining high accuracy on known data with robust extrapolation to new measurements. The charge radii and the odd-even staggering in calcium isotopes are also discussed.
nucl-th0 citations
02
Reaction Cross Sections and $α$ -Cluster Geometry in $^{12}$ C and Be Isotopes
Tianyu Wu · Baohua Sun · Ulf-G. Meißner · Shihang Shen
Reaction cross sections $σ_{R}$ are widely used to infer matter radii, yet their sensitivity to nuclear structure beyond radial one-body distributions is less well understood. We combine complete $A$ -body nucleon configurations sampled from \textit{ab initio} nuclear lattice effective field theory (NLEFT) with event-by-event Monte Carlo Glauber calculations, thereby retaining the many-body correlations encoded in NLEFT. Using a fixed binary-collision prescription determined by the measured energy- and isospin-dependent total nucleon-nucleon cross sections, the calculations capture the overall magnitudes and energy dependence simultaneously for the available data on $^{12}$ C and $^{9}$ Be projectiles on carbon and hydrogen. Controlled randomization of angular correlations at fixed matter root-mean-square radius and spherically averaged one-body radial density produces only a weak change in $σ_{R}$ for $^{12}$ C but approximately a $10%$ increase for $^{9} Be +^{1} H$ . The calculations also capture the measured rise--plateau--sharp-rise--reduction trend across $^{7, 9 - 12}$ Be, a distinctive pattern reflecting the evolution of cluster and halo structures along the isotopic chain. These results show that $σ_{R}$ retains sensitivity to intrinsic many-body geometry beyond a single inferred matter radius, opening a route to studies of exotic $α$ -cluster geometries and spatial nucleon correlations through reaction cross sections.
nucl-th0 citations
03
Toward testing antinucleon $\unicode x 2013$ nucleus optical potentials with antineutron scattering lengths
Hiroyuki Fujioka · Sayaka Ishii
The antineutron $\unicode x 2013$ nucleus scattering length is currently known only indirectly, via antiproton $\unicode x 2013$ nucleus optical potentials fitted to level shifts and widths of antiprotonic atoms. The antineutron $\unicode x 2013$ nucleus and antiproton $\unicode x 2013$ nucleus potentials are related to each other through charge symmetry. We calculate the scattering length from optical potentials proposed for antiprotonic atoms using nucleon density distributions as input. We find that the scattering length for an $N > Z$ nuclide is largely affected by the poorly constrained neutron density distribution and by a possible isovector interaction, one of the mechanisms introduced to reproduce the isotope dependence of antiprotonic $^{40, 48} Ca$ data. For $^{48} Ca$ , the isovector term modifies the scattering length by $0.3 \unicode x 2013 0.4 fm$ ( $0.4 \unicode x 2013 0.5 fm$ ) for the real (imaginary) part, an order of magnitude beyond the uncertainty propagated from the isoscalar potential. As no antineutron $\unicode x 2013$ nucleus scattering data are available below $76 MeV / c$ , a direct measurement with recently proposed low-energy antineutron beams would provide the first access to the antinucleon $\unicode x 2013$ nucleus interaction in the $s$ -wave regime.
nucl-thnucl-ex0 citations
04
Balancing theory uncertainties in ab initio nuclear structure calculations: Many-body truncation versus finite basis size
L. Zurek · U. Vernik · P. Demol · T. Duguet · M. Frosini · A. Tichai
First-principles calculations of atomic nuclei are necessarily incomplete as the Schrödinger equation is solved using approximate methods and due to the finite dimension of the employed Hilbert space. By balancing many-body truncation and basis-size uncertainties, we formalize a criterion for the optimal one-body basis dimension in a given ab initio nuclear structure computation. Next, it is demonstrated that higher-order many-body contributions can be computed using smaller basis sizes than used for the lower orders when a consistent accuracy in the calculation is targeted. Our findings are empirically validated using many-body perturbation theory and coupled-cluster calculations of nuclei spanning a large portion of the nuclear chart using two sets of chiral two- and three-nucleon interactions. The results suggest that considerable computational savings can be obtained using many-body-order-dependent one-body basis sizes.
nucl-th0 citations
05
Symmetries of QCD and their relevance for low-energy nuclear physics
Matthias R. Schindler
QCD, the theory of the strong interactions, is formulated in terms of quarks and gluons, while low-energy nuclear physics deals with hadrons such as protons, neutrons, and pions. Symmetries establish a systematic connection between these two descriptions of strongly-interacting systems. The objective of this article is to review the symmetries of QCD and to explain how they constrain hadronic interactions. Chiral symmetry, which emerges in QCD in the limit of massless quarks, is of particular importance for low-energy nuclear physics. Together with its explicit and spontaneous breaking, chiral symmetry provides the basis for chiral perturbation theory, the effective field theory describing pions and nucleons at low energies.
nucl-thhep-ph0 citations
06
Nonrelativistic Conformal Collider Physics of Multiparticle Point Production
Cyuan-Han Chang🇺🇸 · Subham Dutta Chowdhury🇮🇹 · Ian Moult🇺🇸 · Dam Thanh Son🇺🇸
We define detector operators in the nonrelativistic conformal field theory describing fermions at unitarity. We reduce the problem of computing the momentum distribution and correlation between final particles produced by a local source ("point-produced") to the computation of correlation functions involving the detector operators. The general formalism is applied to the point production of three unitary fermions, where we find the momentum and angular distribution of final particles. We discuss a nonrelativistic version of celestial holography, which maps the asymptotic out-state to a quantum wave function in the so-called "oscillator frame."
↳ hep-thhep-phnucl-th0 citations
07
Probing the electroweak structure of nuclei with rare atoms and molecules
Silviu-Marian Udrescu · Antoine Belley · Jason D. Holt · Gilad Perez · Ronald F. Garcia Ruiz
Precision experiments of atoms and molecules have become a powerful probe of the electroweak structure of atomic nuclei and of physics beyond the Standard Model. We review how the interaction between a nucleus and its surrounding bound electrons can be exploited to precisely measure the electromagnetic, parity-violating, and CP-violating properties of nuclei and their fundamental constituents. We focus on rare, unstable isotopes, surveying the experimental techniques and facilities developed in recent years that have extended these measurements to the most exotic regions of the nuclear chart. Recent advances in the precision control and interrogation of single molecules, together with direct laser excitation of nuclear transitions, are opening new frontiers in nuclear and particle physics. At the same time, progress in nuclear theory, machine learning, and high-performance computing is strengthening the connection between our microscopic description of nature and laboratory observables. In many cases, the precision with which nuclear and particle physics properties can be extracted is now limited not by experiment, but by the molecular, atomic, or nuclear theory required to interpret the measurements. This challenge presents a major opportunity for combined theoretical and experimental advances that will enable future discoveries.
↳ physics.atom-phnucl-exnucl-th0 citations
08
Fourier Transforms of Color Glass Condensate Multi-Wilson-Line Correlators via Filon Quadrature
Haowu Duan🇨🇳 · Si-Wei Dai🇨🇳 · Cong Yi🇨🇳 · Wenbin Zhao🇨🇳
Calculating cross sections in the Color Glass Condensate effective theory requires Fourier transforms of multi-Wilson-line correlators from transverse coordinate space to transverse momentum space. Under the common assumption of impact-parameter independence, each transform reduces to a set of Hankel transforms whose Bessel-function kernels oscillate rapidly at phenomenologically relevant momenta, making direct quadrature prohibitively expensive. We present a Filon-type quadrature, applicable to any integrand, that integrates these oscillatory factors in closed form on the stored coordinate grid, reducing each Hankel transform to a precomputed weight vector and the full nested transform chain to a sequence of matrix products. We develop and validate the method on the deep inelastic scattering dijet cross section beyond the correlation-limit approximation, where an exprel-based reformulation of the quadrupole Wilson-line correlator removes a numerical $0/0$ instability inherent to its standard parametrization. Porting the calculation to the Graphics Processing Unit (GPU), with custom CUDA kernels that fuse the momentum-space contraction directly into the correlator evaluation, brings the runtime for one dipole input down to about two minutes on a single NVIDIA A800, from several hours on a multi-core Central Processing Unit (CPU). We further generalize the algorithm to three sequential Hankel transforms and validate the resulting six-dimensional transform against an analytic Gaussian integrand family with closed-form results at every stage. This general, process-independent algorithm is directly applicable to next-to-leading-order proton-nucleus and electron-ion scattering cross-section calculations performed without the correlation-limit approximation. The code is publicly available at https://github.com/CCNU-CGC-py/FFT_filon.
↳ hep-phnucl-thphysics.comp-ph0 citations
09
Inverse Feshbach's problem: Solvability and solutions
Miloslav Znojil
Given a certain specific, $M$ by $M$ matrix form of the Feshbach's effective (i.e., energy-dependent) Hamiltonian $H_{e f f}^{(M)} (E)$ , the inverse-problem reconstruction of the full-space, $N$ by $N$ matrix Hamiltonian $H^{(N)}$ is considered and reduced to the solution of a coupled set of polynomial algebraic equations. Using computer-assisted symbolic manipulations, an explicit algebraic reconstruction of $H^{(N)}$ is found feasible at not too large $K = N - M$ .
↳ quant-phmath-phmath.MPnucl-th0 citations
10
$Υ (n S)$ Production within Jets at the LHC
Taewook Ha🇨🇳 · Hee Sok Chung🇰🇷 · Daekyoung Kang🇰🇷 · Yunlu Wang🇨🇳 · Haixiang Zhu🇨🇳
Heavy quarkonium production inside jets offers a sensitive probe of QCD dynamics and bound-state formation mechanisms. While recent studies demonstrate that charmonium-in-jet observables effectively discriminate among competing nonrelativistic QCD (NRQCD) long-distance matrix element (LDME) sets, whether this discriminating power persists in the bottomonium sector remains an open question. Here, we present the first phenomenological study of $Υ (1 S)$ , $Υ (2 S)$ , and $Υ (3 S)$ production inside jets using the fragmenting jet function (FJF) framework at next-to-leading order (NLO), incorporating DGLAP evolution, threshold resummation, and feeddown contributions from higher bottomonium states. In sharp contrast to charmonium, we find that bottomonium-in-jet momentum-fraction ( $z_{H}$ ) distributions exhibit a universal shape that is remarkably insensitive to the choice of LDME sets. We show that this universality stems from the strong dominance of the S-wave spin-triplet color-octet ( $^{3} S_{1}^{[8]}$ ) production mechanism reinforced by $χ_{b}$ feeddown transitions. Our predictions capture both the characteristic large- $z_{H}$ peak and the spectral broadening with increasing jet transverse momentum observed in recent CMS measurements. These results establish a clear physical distinction between charmonium and bottomonium fragmentation inside jets, providing a theoretical benchmark for future high-precision measurements at the LHC.
↳ hep-phhep-exnucl-th0 citations
11
Three-body forces in the quark model
Jongheon Baek🇰🇷 · Aaron Park🇰🇷 · Emiko Hiyama🇯🇵 · Sungsik Noh🇰🇷 · Hyeongock Yun🇰🇷 · Kyong Chol Han🇺🇸 · Su Houng Lee🇰🇷
We review the connection between constituent-quark Hamiltonians and QCD and investigate the long-standing difficulty of describing meson and baryon spectra with one common two-body interaction. A Hamiltonian calibrated to ground-state mesons leaves systematic baryon mass residuals, largest in the light-quark sector and decreasing toward heavier flavors. We show that a short-range, color-spin-dependent connected three-quark interaction substantially reduces this incompatibility. Mass-scaled finite-range profiles yield high-accuracy baryon spectra, whereas flavor-independent common-range profiles do not remove the residual flavor pattern. The result is tested on additional ground-state baryons outside the calibration set and through meson--baryon compatibility analyses across several alternative quark-model Hamiltonians. We also benchmark radial and orbital excitations to identify the regime in which a static compact valence Hamiltonian remains reliable, and provide explicit color-spin matrix elements for two- and three-body operators in baryons and multiquark configurations. Within the tested valence-space representations, the results indicate that a mass-dependent short-range connected three-quark interaction provides the missing contribution required for a consistent simultaneous description of meson and baryon ground-state spectra.
↳ hep-phnucl-th0 citations
12
Quantifying uncertainty in the neutron-star equation of state using point estimates and posterior distributions
André Gonçalves da Silva · Ricardo Luciano Sonego Farias
We investigate uncertainty quantification for the neutron-star equation of state (EOS) by comparing point-estimation and distributional inference approaches using the same Chebyshev and piecewise-linear parameterizations. We combine neutron-star mass--radius and gravitational-wave tidal-deformability information within Bayesian, multilayer-perceptron (MLP), and normalizing-flow frameworks. Although the methods yield similar mean EOS behavior, the deterministic MLP produces substantially narrower uncertainty bands at high densities. We show that this behavior is associated with the point-estimation objective, which maps degenerate solutions toward the conditional mean rather than representing the full parameter posterior. By contrast, the normalizing flow yields distributions more consistent with the Bayesian inference. Our results demonstrate that reliable uncertainty quantification of the high-density EOS requires methods that represent conditional probability distributions rather than only point estimates.
↳ astro-ph.HEhep-phhep-thnucl-th0 citations
13
Quantum Magic in High Energy Collision
Ying-Ying Li🇨🇳 · Ian Low🇺🇸 · Yi-Lin Wang🇨🇳 · Zhewei Yin🇨🇳
Quantum magic, or nonstabilizerness, is a quantum resource associated with computational advantage in quantum systems. In high energy collisions, Quantum Electrodynamics (QED) is inefficient at generating magic while the weak mixing angle, a fundamental constant of nature, sits near a value that minimizes magic production in charged-lepton scattering. These observations were made in the laboratory (lab) basis, in which spin is projected along the incoming beam axis. An alternative choice is the helicity basis, in which spin is projected along the direction of motion of each particle. The transformation between these two bases is, in general, not a Clifford operation and therefore can change the amount of magic. We present a detailed study of magic production in both bases for QED and electroweak processes, and compare these results with the basis-invariant non-local magic. In the ultra-relativistic limit, magic production is generally smaller in the helicity basis due to helicity selection rules, while the lab basis generally yields less magic in the non-relativistic regime. We provide circuit realizations of the ultra-relativistic Bhabha amplitudes using linear combinations of unitaries and show that the lab basis construction contains a larger $T$ -gate count at generic scattering angles. Interestingly, in both bases the physical weak mixing angle lies close to the value that minimizes magic production.
↳ hep-phnucl-thquant-ph0 citations

Affiliations

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