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

Affiliations

first authorsco-authorsvia INSPIRE

Producing and Studying Rare Isotopes in e+A Collisions at the Electron-Ion Collider

Light antiproton-nucleus systems at low energies with the ab initio NCSM/RGM method

Quantum stress and torsion distributions in the deuteron

Constraining the ΛΛ interaction with terrestrial and astronomical data

Affiliations

Producing and Studying Rare Isotopes in $e + A$ Collisions at the Electron-Ion Collider

Constraining the $ΛΛ$ interaction with terrestrial and astronomical data