Nuclear Theory·nucl-th

Monday·June 1, 2026

12 papers—7 primary·5 cross-listed

01
[Submitted on 28 May 2026]
Time-ordered Diagrammatic Monte Carlo for atomic nuclei
Stefano Brolli · Carlo Barbieri
Diagrammatic Monte Carlo provides a systematically improvable framework for stochastically resumming many-body expansions to high orders through direct sampling of diagram topologies. We advance our earlier work by introducing a novel time-ordered Diagrammatic Monte Carlo algorithm for the single-particle Green's function. The algorithm is tailored to finite nuclei, formulated in discrete model spaces and applicable to arbitrary two-body interactions. The new time-ordered diagrammatic Monte Carlo algorithm is based on the on-the-fly evaluation of time-ordered Goldstone diagrams, avoiding explicit diagram enumeration and expensive frequency integration. We show the algorithm by computing $^{16}$ O up to fifth order in a reduced model space using optimized reference state orbitals and including effective three-body forces. Benchmarking against established truncation schemes in ab initio nuclear theory demonstrates its potential to overcome the limitations of current many-body approaches.
Comments:
6 pages, 5 figures for the main article; 6 pages, 2 figures for supplemental material
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.30527 [pdf]
1 citation
02
[Submitted on 28 May 2026]
Effects of the Symmetry energy slope on the exotic content of the neutron stars
Luiz L. Lopes🇧🇷
By varying the symmetry energy slope ( $L$ ), I investigate how the exotic content within the interiors of neutron stars changes and how it affects both macroscopic and microscopic quantities. Using two different parametrizations (L3 $ω ρ$ and BigApple), and three different possibilities about the neutron star core (nucleons+hyperons, nucleons+deltas, nucleons+hyperons+deltas), I show that, for the models analyzed in this work, changing the slope barely changes the amount of hyperons, but it can strongly suppress the $Δ$ resonances for large values of $L$ . I also show that, in general, the presence of exotic content will be more evident for lower values of $L$ than for large ones. Differences and similarities between the two parametrizations are also analyzed.
Comments:
16 pages - 6 Figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th)
arXiv:
2605.30554 [pdf]
1 citation
03
[Submitted on 29 May 2026]
Optimized basis of covariant density functional theory: point coupling functionals and excited states
A. Dalbah · A. V. Afanasjev · B. Osei
The present investigation focuses on the improvement of the accuracy of the description of physical observables of interest in moderately sized fermionic basis within the framework of covariant density functional theory. It extends previous study of Ref. [1] to point coupling (PC) covariant energy density functionals (CEDFs) and to excited states. Using as a benchmark the solutions corresponding either to infinite fermionic basis or those extrapolated to such a basis it is shown that the optimization of oscillator frequency $ℏ ω_{0}$ of the harmonic oscillator (HO) basis leads to a substantial improvement in the description of different physical observables in the fermionic basis truncated at $N_{F}$ . Globally optimized scaling factors $f_{o pt} (A)$ of the oscillator frequency and the sizes $N_{F}^{ε}$ of the HO bases providing the required accuracy $ε$ in the calculations of the binding energies are generated for the PC functionals. The optimization of the basis also significantly improves the accuracy of the description of potential energy curves, defining the fission barriers and fission isomers in actinides and superheavy nuclei, provided that the size of the basis is at least equal to $N_{F} = 20$ . The optimization of the HO basis improves the accuracy of the description of the energies of bound single-particle states: the only exceptions are weakly bound neutron states with low orbital momenta $l = 0$ , 1 and 2. It is demonstrated for the first time that the halo densities of neutron halo nuclei generated in the coordinate space calculations are well reproduced in the calculations with very large fermionic HO bases.
Comments:
16 pages, 15 figures, submitted to Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.30669 [pdf]
1 citation
04
[Submitted on 29 May 2026]
Dynamical selection of fragment shell effects in spontaneous fission of $^{240}$ Pu, $^{232}$ Th, and $^{264}$ Fm
Qiafeng Chen · Fuchang Gu · Yingge Huang · Erxi Xiao · Yinu Zhang · Jun Su
Understanding how fragment shell effects influence spontaneous fission mass yields remains a central challenge in nuclear fission theory. This work investigates the role of shell effects in the spontaneous fission of $^{240}$ Pu, $^{232}$ Th, and $^{264}$ Fm by combining microscopic collective dynamics with fragment-level shell analysis. A two-step framework is employed: first, the tunneling from the inner to outer turning points is described using the Wentzel-Kramers-Brillouin approximation along the least-action path on a potential energy surface calculated from constrained Hartree-Fock-Bogoliubov theory. Second, the dissipative descent from the outer turning points to scission is simulated via Langevin dynamics in a large collective space of quadrupole and octupole deformations. Fragment shell effects are quantified using smoothed level density indicators for representative even-even fragment pairs extracted from Langevin scission configurations. The analysis reveals that enhanced yields arise from a coherent overlap among dynamically populated scission configurations, low-energy regions on the fragment potential energy surfaces, and low neutron and/or proton level densities near the Fermi surface. Proton shell effects provide persistent microscopic selectivity in both light and heavy fragments across asymmetric channels, while neutron shell effects offer additional stabilization. Deformed shell effects at finite quadrupole and octupole deformations play a crucial role in stabilizing asymmetric fission channels. This work demonstrates that fission fragment yields reflect shell-favored configurations that are made accessible by the potential energy surface topology and populated by stochastic dynamics, with the largest yields corresponding to configurations where shell gaps provide maximal binding.
Comments:
12 pages, 9 figures, comments and suggestions are welcome
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.30828 [pdf]
PRC(2026)·0 citations
05
[Submitted on 29 May 2026]
Neural-network excited states of $A = 4$ nuclei and hypernuclei
Zi-Xiao Zhang🇮🇳 · Yi-Long Yang🇮🇳 · Xiao-Lu Qian🇮🇳 · Wan-Bing He🇮🇳 · Peng-Wei Zhao🇮🇳 · Bing-Nan Lu🇮🇳 · Yu-Gang Ma🇮🇳
We present the first variational Monte Carlo study of nuclear and hypernuclear excited states within the neural-network quantum states (NQS) framework. We implement both the overlap penalty (OP) and natural excited state (NES) methods to compute low-lying excitation spectra. To address the spin contamination in hypernuclear calculations, we propose a quantum number targeting (QNT) technique for the OP method. Both the OP-QNT and NES methods can reproduce diagonal observables, such as energies and spatial structures, in excellent agreement with rigorous benchmarks. We further provide, to our knowledge, the first \textit{ab initio} calculation of the $M 1$ transition strength for $_{Λ}^{4} H$ . The calculated transition strength is consistent with the weak-coupling limit, exhibiting a $\sim$ 1.3\% suppression. This work demonstrates that NQS can be elevated from ground-state solvers to practical tools for nuclear and hypernuclear spectroscopy.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.30944 [pdf]
2 citations
06
[Submitted on 29 May 2026]
High-Dimensional Bayesian Calibration of Expensive Nuclear Models with Differentiable Emulation
Jin Lei
Full Bayesian calibration of expensive nuclear models has been blocked not by the cost of any single solve, but by the absence of exact likelihood gradients in legacy parameter-dependent operators, which forces gradient-free samplers to spend $O (1 0^{5})$ evaluations exploring high-dimensional correlated posteriors. I introduce DREAM, a differentiable calibration strategy in which the parameter-dependent operator is sampled offline by any legacy code, compressed by singular value decomposition, and reconstructed online in a differentiable framework so that automatic differentiation delivers exact likelihood gradients through the full forward solve at the cost of one additional evaluation per Hamiltonian Monte Carlo step. The construction is operator-level and depends only on smooth, compressible parameter dependence; the underlying physics solver is treated as a black box. As a representative demonstration, DREAM is applied to a continuum-discretized coupled-channels (CDCC) analysis of $d$ + $^{58}$ Ni elastic scattering at $20$ ~MeV with eighteen optical-potential parameters, for which No-U-Turn Sampling converges on a single GPU in under ten minutes from a cold start with zero divergent transitions, yielding a full Bayesian posterior for a breakup reaction. The mean emulator error is more than an order of magnitude below the inferred model discrepancy, so the posterior is set by the reaction model rather than the surrogate. Treating the Koning-Delaroche systematics as an informative prior, the data update the well-determined parameter combinations, raising the mean deuteron surface absorption about $36%$ above the Koning-Delaroche value, while the under-determined directions remain at the prior; this is a representative payoff that the multi-energy datasets DREAM is designed to accommodate can sharpen into a full physics interpretation.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.30980 [pdf]
0 citations
07
[Submitted on 29 May 2026]
Accessing Exotic Hadronic States via Charmed-Meson Femtoscopy in Relativistic Heavy-Ion Collisions
Jiaxing Zhao🇩🇪 · Taesoo Song🇩🇪 · Elena Bratkovskaya🇩🇪 · Joerg Aichelin🇫🇷
The two-particle correlation function measured in femtoscopic analyses provides access to the interaction potentials between emitted particles. This offers a unique opportunity to investigate interactions among charmed mesons and to explore the nature of possible exotic hadronic states. In this Letter, we study femtoscopic correlations of various charmed-meson pairs in relativistic heavy-ion collisions. The dynamical evolution of the system and charm hadron production are described within the Parton-Hadron-String Dynamics (PHSD) transport approach, while the correlation functions are computed using the Correlation Analysis Tool using the Schrödinger equation (CATS). We demonstrate that heavy-ion collisions provide a significantly more favorable environment than $pp$ collisions for accessing charmed meson femtoscopic correlations. This arises from enhanced charm-quark production, reduced relative momenta due to in-medium energy loss, and a strong suppression of initial-state correlations. Our results indicate that femtoscopic measurements in heavy-ion collisions offer a sensitive probe of charmed meson interactions and possible hadronic molecular states.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2605.31527 [pdf]
0 citations
08
[Submitted on 28 May 2026] (cross-list from hep-ph)
Factorizing quarkonium production matrix elements using effective field theory
Marston Copeland🇺🇸 · Ivan Vitev🇺🇸
We use effective field theory to factorize production matrix elements that appear in quarkonium cross sections in NRQCD. By applying a Hubbard-Stratonovich transformation we show that the soft and ultrasoft sectors of NRQCD can be decoupled from the heavy quark and antiquark fields in a hybrid vNRQCD/pNRQCD Lagrangian at leading order in the velocity power counting. This enables us to separate quarkonium production matrix elements in terms of matrix elements of color-singlet composite fields, which we can write as the wavefunction at the origin, and state independent vacuum correlators of chromo-electric and chromo-magnetic gluon fields. This approach verifies powerful connections between the LDMEs of different S-wave vector quarkonium states, originally derived using pNRQCD. Additionally, we find new operator contributions for the color-octet P-wave mechanism, which satisfy a similar set of relationships. Finally, this approach allows us to factorize the production matrix elements that appear in the transverse momentum dependent factorization framework, known as TMD soft transition functions, in terms of state independent gluon correlators. This work restores some universality for TMD production operators and dramatically improves the predictive power of NRQCD in the TMD framework.
Comments:
48 pages, 10 figures, 3 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2605.30441 [pdf]
4 citations
09
[Submitted on 29 May 2026] (cross-list from hep-ph)
Functional renormalization group study of the jet quenching parameter near the QCD critical end point
Yi-zhen Huang🇨🇳 · Shi Yin🇩🇪 · Sheng-nan Han🇨🇳 · Jing Wu🇨🇳 · Feng Li🇨🇳 · Wei-jie Fu🇨🇳
We investigate the jet quenching parameter $q^$ in the QCD phase diagram within a QCD-assisted low-energy effective theory using the functional renormalization group (fRG). Following the formalism that relates $q^$ to the spectral functions of the chiral order-parameter field, we compute the $σ$ and $π$ meson contributions to $q^$ at finite temperature and baryon chemical potential from analytically continued mesonic two-point functions. We find that $q^$ receives appreciable contributions mainly above the chiral phase boundary and exhibits a pronounced enhancement at large baryon chemical potential as the chiral crossover sharpens toward the critical end point (CEP), a behavior consistent with the picture of partonic critical opalescence (PCO), a pronounced enhancement of jet transverse momentum broadening induced by the critical $σ$ field fluctuations.
Comments:
12 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2605.30816 [pdf]
1 citation
10
[Submitted on 29 May 2026] (cross-list from cond-mat.quant-gas)
Functional methods for quantum thermodynamics
Sibo Wang · Samuel Degen · Haozhao Liang
The functional renormalization group provides a nonperturbative and systematically improvable route to constructing density functionals for quantum many-body systems from microscopic Hamiltonians. Here we advance this program by benchmarking functional-renormalization-group density functional theory (FRG-DFT) against the exact thermodynamics of the single-site Bose-Hubbard model. This model provides an ideal testing ground because it is analytically solvable, yet remains subtle in the imaginary-time coherent-state path integral, where a naive continuum treatment generates a spurious self-interaction. We show that a careful Hubbard-Stratonovich derivation identifies the self-interaction correction term that must be included in the FRG-DFT flow to recover the exact thermodynamics. We then systematically compare several closures of the resulting hierarchy of flow equations for the free energy, chemical potential, and connected density correlators over broad ranges of density, temperature, and interaction strength. The benchmark shows that the free energy is comparatively robust, whereas the chemical potential and fluctuation observables provide much sharper diagnostics of the hierarchy closure. A maximum-entropy closure gives the most accurate overall description and reproduces even the low-temperature oscillatory structure of the connected two-density correlator. These results identify two general requirements for functional approaches to quantum thermodynamics: the renormalization group flow equation must retain the equal-time contact subtraction to avoid spurious self-interactions, and any closure of the hierarchy must preserve the statistical consistency of density correlators. This work provides a controlled foundation for deriving ab initio density functionals for quantum many-body systems across condensed-matter, ultracold-atom, and nuclear physics, as well as quantum chemistry.
Comments:
24 pages, 14 figures; comments are welcome
Subjects:
Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
2605.31112 [pdf]
0 citations
11
[Submitted on 29 May 2026] (cross-list from hep-ph)
Radiative Corrections to Elastic Lepton-Proton Scattering with Focus on Two-Photon-Exchange Diagrams
Daniel Crowe🇺🇸 · Syed Mehedi Hasan🇩🇪 · Doreen Wackeroth🇺🇸
Lepton (electron and muon) scattering experiments are excellent tools to gain insight into the nucleon structure. Elastic electron-proton scattering probes the spatial distribution of charge and magnetization inside the proton, and comparing electron-proton and muon-proton scattering data tests lepton universality. The availability of a plethora of scattering data with increased precision and observed discrepancies such as the proton form factor puzzle and the proton radius puzzle motivated a renewed effort to improve the theoretical framework. Realizing that the one-photon-exchange approximation (OPE), i.e. the Born approximation, is not sufficient, radiative corrections in QED, especially the two-photon-exchange (TPE) diagrams, are under investigation. The TPE diagrams are of special interest among the radiative corrections, since they depend on the proton structure. In this work, we present a complete calculation of QED radiative corrections to elastic electron-proton and muon-proton scattering at next-to-leading order, taking into account loop-momentum-dependent form factors. In the discussion of their numerical impact on lepton-proton scattering cross sections, we pay special attention to the TPE diagrams and compare them with existing theoretical predictions and lepton-proton scattering data.
Comments:
43 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2605.31123 [pdf]
0 citations
12
[Submitted on 29 May 2026] (cross-list from hep-ph)
Deeply bound dibaryon $d^{*} (2380)$ from meson-exchange saturation $ΔΔ$ effective field theory
Prin Sawasdipol🇹🇭 · Chinadanai Bubpatate🇹🇭 · Daris Samart🇹🇭
We propose an RG-improved effective-field-theory framework for the deeply bound dibaryon $d^{*} (2380)$ , a $ΔΔ$ bound state in the $(J, I) = (3, 0)$ $^{7} S_{3}$ channel. Its binding momentum $γ ≃ 320$ MeV gives $γ / m_{π} ≃ 2.3$ , indicating the need to re-organize the short-range dynamics beyond a formal pionless EFT. We match the large- $N_{c}$ -constrained pionless contact potential to a meson-exchange-saturated contact interaction in which the $σ, ρ, ω$ dynamics are integrated out at the hadronic scale $m_{V}$ , yielding the controlled expansion parameter $γ / m_{V} ≃ 0.42$ . Normalizing the contact coupling to the deuteron and substituting the phenomenological CD-Bonn couplings gives $B_{ΔΔ} ≃ 96$ MeV. The $≃ 14%$ discrepancy from $B_{exp} = 84$ MeV is of the natural size of $O (1/ N_{c}^{2}) ≃ 11%$ corrections to the $N N$ potential, confirming compatibility with a controlled EFT expansion organized around the finite-range hadronic scale. As a result, the observed $d^{*} (2380)$ pole emerges from the virtual state to bound state by using the EFT re-organization in this work.
Comments:
7 pages, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2605.31578 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE