Nuclear Theory·nucl-th

Monday·February 23, 2026

9 papers—4 primary·5 cross-listed

01
Producing and Studying Rare Isotopes in $e + A$ Collisions at the Electron-Ion Collider
Mark Ddamulira🇺🇸 · Abhay Deshpande🇺🇸 · Mark C. Harvey🇺🇸 · Wenliang Li🇺🇸 · Niseem Magdy🇺🇸 · Brynna Moran🇺🇸 · Pawel Nadel-Turonski🇺🇸 · Charles Joseph Naim🇺🇸 · Stacyann Nelson🇺🇸 · Isaiah Richardson🇺🇸 · Barak A. Schmookler🇺🇸 · Oleg B. Tarasov🇺🇸
The Electron--Ion Collider (EIC) offers a unique environment to study kinematically controlled lepton--nucleus ( $e + A$ ) reactions, where a primary hard scattering is followed by an intranuclear cascade and the subsequent statistical de-excitation of the nuclear remnant. Utilizing the \soft{BeAGLE} model, we demonstrate that event-by-event fluctuations in nucleon removal and energy deposition populate a diverse ensemble of excited remnants. Furthermore, we show that varying the target mass systematically shifts the distribution of these remnants across the $(N, Z)$ plane. Although this excited prefragment remnant is not directly observable, its properties are shown to be strongly correlated with final-state fragments; specifically, the largest nuclear residue and the intensity of evaporation yield serve as effective experimental proxies for event-level remnant characterization. We also evaluate photon observables essential for nuclear spectroscopy. While various photon sources overlap significantly in pseudorapidity, we find that in the nucleus-rest frame, the low-energy spectrum is dominated by de-excitation $γ$ rays and exhibits distinct discrete structures. These findings motivate an EIC research program that correlates rare-isotope production and de-excitation radiation with well-defined initial conditions, providing a collider-based approach to nuclear spectroscopy that is complementary to existing fixed-target facilities.
nucl-thhep-phnucl-exJ.Phys.G(2026)·0 citations
02
Light antiproton-nucleus systems at low energies with the ab initio NCSM/RGM method
Alireza Dehghani🇫🇷 · Guillaume Hupin🇫🇷 · Sofia Quaglioni🇺🇸 · Petr Navrátil🇨🇦
The availability of low-energy antiproton beams at the CERN Antiproton Decelerator has renewed interest in using antimatter as a probe of nuclear structure and in forming exotic antiprotonic few-body systems. In this work, we extend the ab initio no-core shell model combined with the resonating group method (NCSM/RGM), which was successfully applied to light-nucleus structure and reactions, to antiproton-nucleus dynamics at low energies. The NCSM/RGM formalism is adapted to antiproton projectiles by removing the requirement of antisymmetrization under exchange of target and projectile constituents, while retaining a fully microscopic description of the nuclear target and the relative motion. We focus on the lightest systems, $p ˉ + d$ , $p ˉ +^{3} H$ , and $p ˉ +^{3} He$ , for which benchmarking against exact solutions of the Schrödinger equation enables stringent validation and helps disentangle methodological uncertainties -- e.g., those associated with the choice of configurations included in the NCSM/RGM expansion -- so that the dominant residual uncertainty can be attributed to the $N N ˉ$ interaction. We compute phase shifts, scattering lengths, cross sections, antiprotonic-atom level shifts and widths, nuclear quasibound energies, and annihilation densities. We find that the hard short-range components of the meson-exchange-based $N N ˉ$ interaction lead to slow convergence of the NCSM/RGM kernels expanded in a harmonic-oscillator basis, requiring exceptionally large model spaces and posing significant numerical challenges. We discuss practical strategies to mitigate these limitations and assess the impact of missing closed-channel configurations, which is a significant source of uncertainties in very light systems.
nucl-thPRC(2026)·2 citations
03
Quantum stress and torsion distributions in the deuteron
Wim Cosyn🇺🇸 · Adam Freese🇺🇸 · Alan Sosa🇺🇸
Stress distributions in the deuteron are related to form factors of the asymmetric energy-momentum tensor through three-dimensional Fourier transforms. There are eleven such form factors, which we calculate in an impulse approximation. We compare the obtained form factors to prior results for the six form factors that have been previously calculated. We then elaborate on the formalism for relating the form factors to internal distributions of mass, mass flux, momentum, stresses, and forces, and obtain results for all of these distributions. We obtain the principal stresses for the symmetric part of the stress tensor, and show that the antisymmetric part describes reorientation of fermion spin by torsion stress when the nucleon moves between the S- and D-waves. Force distributions in the nucleons depend on the so-called non-conserved form factors through the Cauchy momentum equation, and are non-radial owing to the presence of tensor forces and spin-orbit coupling.
nucl-thhep-phquant-phPRC(2026)·2 citations
04
Constraining the $ΛΛ$ interaction with terrestrial and astronomical data
Yusuke Tanimura🇰🇷 · Chang Ho Hyun🇰🇷 · Myung-Ki Cheoun🇰🇷
Terrestrial double- $Λ$ hypernuclear data and astronomical observations of neutron stars provide complementary constraints on the $ΛΛ$ interaction. In this work, we investigate the $ΛΛ$ interaction within a Skyrme energy density functional framework based on the KIDS (Korea-IBS-Daegu-SKKU) models. We employ a Skyrme-type $ΛΛ$ interaction that includes the standard $s$ - and $p$ -wave terms, as well as a density-dependent term that effectively represents an $N ΛΛ$ three-body force. The $s$ -wave terms are constrained using data on double- $Λ$ hypernuclei supplemented by pseudodata obtained from core + $2Λ$ three-body model calculations including heavier hypernuclei. We show that the data on heavier systems are essential to simultaneously constrain the two $s$ -wave parameters. We further explore the impact of the $p$ -wave and $N ΛΛ$ components on the neutron-star properties and find that appropriate repulsive contributions of these terms yield consistency with current neutron-star mass-radius observations. These results indicate that the present framework provides phenomenologically acceptable equations of state for dense $(N, Λ)$ matter over a wide range of densities and highlight the importance of future experimental data on heavier double- $Λ$ hypernuclei.
nucl-thastro-ph.HEastro-ph.SRPTEP(2026)·2 citations
05
Higher order quantization conditions for two-body scattering with spin
Lucas Chandler🇺🇸 · Frank X. Lee🇺🇸 · Andrei Alexandru🇺🇸
We examine the Lüscher quantization condition to high order for the scattering of a spinless particle and a spin-1/2 particle in a periodic box. First, we derive the quantization conditions in a non-relativistic framework up to total angular momentum $J = 11/2$ in both cubic and elongated geometries, and for both rest and moving frames. Then, we introduce a method to transparently cross-check their convergence, using both quantized energy levels in the box and infinite-volume phase shifts for the same potential. We clarify how to incorporate spin-orbit coupling into the formalism and show in detail how the quantization conditions converge order by order in the various irreducible representations. In all, we validated 19 quantization conditions (12 in cubic box, 7 in elongated box). This is a necessary step in applying the method in precision studies of systems in finite volume with half-integer spin, such as meson-baryon scattering.
↳ hep-lathep-phnucl-thPRD(2026)·0 citations
06
Observation of Robust and Coherent Non-Abelian Hadron Dynamics on Noisy Quantum Processors
Fran Ilčić🇮🇳 · Ritajit Majumdar🇮🇳 · Emil Mathew🇮🇳 · Md. Osama Ali🇮🇳 · Nathan Earnest-Noble🇺🇸 · Indrakshi Raychowdhury🇮🇳
The real-time evolution of strongly interacting matter remains a frontier of fundamental physics, as classical simulations are hampered by exponential Hilbert space growth and rapid, unmanageable growth of quantum entanglement. This study reports the quantum simulation of hadron dynamics within a $(1 + 1)$ -dimensional SU(2) lattice gauge theory using a 156-qubit IBM superconducting processor. Leveraging a hardware-efficient Loop-String-Hadron (LSH) encoding, we simulate the dynamics of the physical degrees of freedom on a $60$ -site lattice in the weak-coupling regime, as a crucial step toward the continuum limit. The hardware data reveal confined meson propagation and early-time oscillations of the mesonic profile, from which we extract a breathing-mode frequency as a spectroscopic observable. Benchmarking against tensor-network simulations of the full LSH Hamiltonian and Pauli-propagation simulations of the noiseless circuit supports the validity of the physical approximation, the quantum algorithm and the observed dynamics within the accessible time window. These results show that physics-native encodings can enable scalable access to coherent non-Abelian real-time dynamics on noisy quantum hardware.
↳ hep-latcond-mat.str-elhep-thnucl-th+115 citations
07
The hyperfine interaction as a probe of the microscopic structure of the atomic nucleus
Denis Janković🇰🇷 · Jean-Gabriel Hartmann🇫🇷 · Johann Bartel🇫🇷 · Hervé Molique🇫🇷 · Ludovic Bonneau🇫🇷 · Paul-Antoine Hervieux🇫🇷
The study of highly charged electronic and muonic hydrogen-like ions, provides an intriguing way to probe the internal structure of their atomic nuclei. In this work, we use nuclear structure calculations to accurately calculate the hyperfine splitting of electronic and muonic hydrogen-like ions, focusing in particular on the incorporation of finite-volume corrections, such as Bohr-Weisskopf and Breit-Rosenthal, due to the penetration of the electron and muon wavefunction into the nuclear electric charge and magnetic dipole densities. These corrections are essential for refining our understanding of the nuclear magnetic dipole and electric quadrupole moments. Our simulations use a Skyrme-Hartree-Fock-BCS model known for its effectiveness in modeling well-deformed nuclei such as $^{159} Tb^{64 +}$ and $^{165} Ho^{66 +}$ , with particular emphasis on $^{161, 163} Dy^{65 +}$ isotopes. It can also be generalised to multi-electron ions by studying the hyperfine anomaly between two isotopes.
↳ physics.atom-phnucl-thquant-ph0 citations
08
Quark-meson diquark model and color superconductivity in dense quark matter
Jens O. Andersen🇳🇴 · Mathias P. Nødtvedt🇳🇴
We consider the two- and three-flavor QMD models as renormalizable low-energy models for QCD at finite quark chemical potentials with quarks, mesons, and diquarks as effective degrees of freedom. Using the on-shell scheme the parameters in the scalar sector can be fixed and expressed in terms of observed meson masses and decay constants. The remaining parameters can be varied. In the QMD models, all the symmetries are global, including the $S U (N_{c})$ symmetry. The breaking of the global symmetries gives rise to a number of Goldstone bosons depending on the symmetry-breaking pattern, i.e. whether the system is in the 2SC phase or the color-flavor-locked (CFL) phase. This is in contrast to perturbative QCD, where some of the gauge bosons become massive via the Higgs mechanism. We classify the Goldstone bosons and show that their type and number are in accordance with general counting rules. The thermodynamic potential $Ω$ is calculated in the mean-field approximation, where we include quark loops, while mesons and diquarks are treated at tree level. As important applications, we study the properties of the pion-condensed phase at finite isospin chemical potential, and the 2SC and CFL phases at finite baryon chemical potential. We present a few numerical results focusing on the speed of sound, gaps, and condensates. It is shown that the BCS gaps approaches a constant for large isospin and baryon chemical potentials and that the speed of sound approaches the conformal value from above in the same limit.
↳ hep-phhep-latnucl-th4 citations
09
On self-dualities for scalar $ϕ^{4}$ theory
Paul Romatschke🇦🇹
Scalar field theory is studied by constructing interacting saddle point expansions in the symmetric and broken phase, respectively. Focusing on analytically tractable saddle expansions, it is found that broken and symmetric phases are related by sign flip of the quartic coupling. Applications to dimensions $d < 4$ recover previous results for the phase diagram, whereas $d = 4$ is possibly new.
↳ hep-thcond-mat.quant-gasnucl-th3 citations

Affiliations

first authorsco-authorsvia INSPIRE