Nuclear theory sits at the fascinating intersection of particle physics and the forces that hold our universe together. This field explores how protons and neutrons bind inside atomic nuclei, seeking to understand the fundamental interactions that govern matter at its most dense and energetic levels. While the mathematics involved can be incredibly complex, the core questions are deeply human: how does the universe function at its smallest scales, and what happens when we push matter to its limits?

At Gist.Science, we make these cutting-edge discoveries accessible by processing every new preprint published in this category on arXiv. Our team transforms dense academic manuscripts into clear, plain-language summaries alongside detailed technical overviews, ensuring that both experts and curious readers can grasp the latest breakthroughs without getting lost in the jargon. Below are the latest papers in nuclear theory, distilled and ready for you to explore.

Binding energy of the TbbT_{bb} tetraquark from lattice QCD with relativistic and nonrelativistic heavy-quark actions

This paper presents a new lattice QCD determination of the TbbT_{bb} tetraquark binding energy using relativistic heavy-quark actions, yielding results of approximately $-79$ MeV that are consistent with prior NRQCD findings but exhibit reduced magnitude due to the exclusive use of symmetric correlation matrices with local four-quark operators.

Jakob Hoffmann, Stefan Meinel2026-03-16⚛️ hep-lat

How well known is the compressibility of nuclear matter?

This paper challenges the widely accepted value of nuclear matter compressibility (K\sat240K_\sat \approx 240 MeV) by demonstrating that microscopic Energy Density Functionals with enhanced flexibility can yield significantly lower values (around 160 MeV) while still reproducing experimental data, thereby suggesting a new methodology for determining this property and implying a lower quark onset density for neutron stars.

J. Margueron, E. Khan2026-03-16⚛️ nucl-th

Slowly Rotating Two-Fluid Neutron Stars: Coupled Frame-Dragging, Inertia Splitting, and Universal Relations

This paper establishes a fully relativistic framework for slowly rotating two-fluid neutron stars that reveals intrinsic collective rotational eigenmodes and demonstrates that the preservation or breakdown of rotational-tidal universality depends on dark-sector microphysics rather than simply the presence of an additional gravitationally coupled component.

Ankit Kumar, Hajime Sotani2026-03-16⚛️ nucl-th

Probing the chiral and U(1)U(1) axial symmetry restoration via meson susceptibilities in holographic QCD

Using a soft-wall holographic QCD model calibrated to reproduce the physical pion mass and pseudocritical temperature, this study demonstrates that while chiral symmetry restoration is clearly signaled by the degeneracy of chiral partner meson screening masses near TpcT_{\rm pc}, the restoration of U(1)U(1) axial symmetry occurs at a distinctly higher temperature (T0.190T \sim 0.190 GeV), highlighting a qualitative limitation of the model in describing the U(1)U(1) axial anomaly compared to Lattice QCD.

Hiwa A. Ahmed, Danning Li, Mamiya Kawaguchi, Mei Huang2026-03-16⚛️ nucl-th

Threshold-Aligned Pygmy Dipole Strength in Astrophysical (n,γ)(n,\gamma) and (γ,n)(\gamma,n) Reactions

This study demonstrates that reaction-rate enhancements in r-process nucleosynthesis are primarily driven by the specific alignment of low-lying pygmy dipole strength with the neutron separation threshold, rather than the total low-energy strength, thereby highlighting the critical need for accurate microscopic descriptions of dipole strength near the neutron threshold.

T. Ghosh, A. Kaur, N. Paar2026-03-16⚛️ nucl-th

π\pi, K, and p production in high-multiplicity pp collisions at s=13\sqrt{s} = 13 TeV

This paper presents new measurements of π\pi, K, and p production in high-multiplicity proton-proton collisions at 13 TeV that reveal mass-dependent spectral hardening and enhanced baryon-to-meson ratios similar to heavy-ion collisions, suggesting that particle production scales with charged-particle multiplicity rather than system size or collision energy, while highlighting that current Monte Carlo models fail to consistently describe all observed features.

ALICE Collaboration2026-03-16⚛️ nucl-ex

Measurement of correlations between elliptic flow and mean transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC

Using the full LHC Run 2 dataset, this ALICE study reports the first measurements of event-by-event correlations between elliptic flow and mean transverse momentum in pp, p-Pb, and Pb-Pb collisions, revealing non-monotonic trends and system-consistent values at low multiplicity that challenge current theoretical models and provide new constraints on the origin of collectivity in small collision systems.

ALICE Collaboration2026-03-16⚛️ nucl-ex

Decoding the structure near the π+π\pi^+\pi^- mass threshold in ψ(3686)J/ψπ+π\psi(3686) \rightarrow J/\psi \pi^+\pi^- decays

Using dispersion theory to account for strong pion-pion final-state interactions, this study demonstrates that the substructure near the π+π\pi^+\pi^- threshold in ψ(3686)J/ψπ+π\psi(3686) \rightarrow J/\psi \pi^+\pi^- decays can be reproduced without invoking an extra resonance, attributing the observed dip primarily to a helicity-flip amplitude rather than the virtual exchange of the Zc(3900)Z_c(3900) state.

Yun-Hua Chen, Xiang-Kun Dong, Feng-Kun Guo, Christoph Hanhart, Bastian Kubis2026-03-13⚛️ hep-ex