Nuclear Theory·nucl-th

Tuesday·March 17, 2026

9 papers—4 primary·5 cross-listed

01
[Submitted on 13 Mar 2026]
Computing neutrino cross sections from Euclidian responses
Alexis Nikolakopoulos🇺🇸 · Noemi Rocco🇪🇸
Energy integrated neutrino cross sections are integrals of nuclear responses weighted with kinematic prefactors. We decompose the prefactors into a limited set of functions of energy transfer and show the relevant integrals are the moments of the responses, and integrals weighted with $1/ (a + ω)^{n}$ with $n \leq 2$ . These can be directly obtained from the Euclidean response, avoiding the need for inversion of the Laplace transform. As a proof of concept we study the procedure with toy-model responses for the quasielastic peak. We show that the different contributions can be straightforwardly organized in terms of relative importance, and how flux-averaged cross sections can be obtained. Using a realistic model for the response and numerical uncertainty we show that it is feasible to obtain the required integrals from the Euclidean response, with large uncertainties only for the third moment. Due to kinematic restrictions, the integrals contain contributions from the unphysical region for neutrino scattering, coming from high-momentum nucleons. We show that (in the absence of two-body currents) robust corrections for this contamination are obtained from the single-nucleon momentum distribution. These results present an opportunity to compute certain neutrino cross sections with ab-initio methods with controlled uncertainties.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.13619 [pdf]
0 citations
02
[Submitted on 16 Mar 2026]
A Note on the Consistent- $Q$ Scheme for Odd-Odd Nuclei
Xiao Tong Li · Xi Deng · Yu Zhang
Compared with even-even nuclear systems, the dynamical structure of low-lying excited states in odd-odd nuclei poses significantly greater theoretical challenges. The interacting boson fermion fermion model provides an effective framework for capturing the structural properties of odd-odd nuclei. Within this algebraic framework, the consistent- $Q$ scheme, which was widely used to map nuclear shape phase diagram, is extended to odd-odd systems to examine how unpaired nucleons influence level structures and their evolution across prototypical transitional regions. The results demonstrate that the presence of unpaired nucleons does not suppress the critical behavior characterizing level evolution across the U(5)-SU(3), U(5)-O(6) and SU(3)-O(6) shape transitions, suggesting that shape phase transitions remain a fundamental mechanism governing the low-lying structural evolution of odd-odd nuclei in the heavy and intermediately-heavy mass regions.
Comments:
5 page, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.14932 [pdf]
0 citations
03
[Submitted on 16 Mar 2026]
A systematic study of global spin polarizations and correlations of hadrons with different spins in relativistic heavy ion collisions
Ji-peng Lv🇨🇳 · Zi-han Yu🇨🇳 · Xiao-wen Li🇨🇳 · Zuo-tang Liang🇨🇳
Based on the formalism presented in [1], we make a systematic study of spin polarizations of hadrons with different spins including vector mesons, spin-1/2 and spin-3/2 hyperons and spin correlations of hadron-hadron such as hyperon-hyperon, hyperon-vector meson and vector meson-vector meson in relativistic heavy ion collisions. We present the results obtained and discuss the physical consequences in special cases. These results can be used for further numerical studies and for references of future experiments as well.
Comments:
21 pages
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2603.15135 [pdf]
1 citation
04
[Submitted on 16 Mar 2026]
Bridging Theory and Data: Correcting Nuclear Mass Models with Interpretable Machine Learning
Yanhua Lu · Tianshuai Shang · Pengxiang Du · Jian Li · Haozhao Liang
Nuclear mass prediction is one of the core issues in nuclear physics research, yet it faces the challenge of small-sample datasets with high complexity. This study introduces the Kolmogorov-Arnold Network (KAN) into the refinement of nuclear mass models, proposing an efficient and interpretable solution. By constructing the KAN-WS4 hybrid model, the prediction accuracy is significantly improved (the root mean square error is reduced from 0.3 MeV to 0.16 MeV). Furthermore, leveraging the intrinsic interpretability of KAN, feature importance analysis reveals that the proton number is the most critical factor influencing residuals, indicating potential systematic biases in proton-related terms within existing theoretical models. The method's generality is demonstrated across five mass models. This study shows that KAN provides a novel approach to small-sample, high-complexity scientific problems. Its interpretability facilitates the data-driven discovery of physical laws, promising broad applicability to key nuclear physics issues.
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.15203 [pdf]
1 citation
05
[Submitted on 13 Mar 2026] (cross-list from astro-ph.HE)
Critical slowing down and bulk viscosity in binary neutron star mergers
Jamie M. Karthein🇺🇸 · Maneesha Sushama Pradeep🇮🇳 · Rachel Steinhorst🇺🇸
Hydrodynamic simulations of neutron star mergers rely on the clear separation between the strong-interaction, weak-interaction, and hydrodynamic timescales. In this effective framework, weak Urca interactions are typically the slowest microscopic processes, and therefore the Urca rate determines the bulk-viscous dissipation. This assumed hierarchy of dissipative mechanisms can be decisively altered, without invalidating hydrodynamics, if the trajectory of the matter in a neutron star merger passes through the vicinity of a possible low temperature QCD critical point. The enhanced density fluctuations lead to critical slowing down and rapid growth of transport coefficients including bulk viscosity. While this growth is regulated by finite-time effects, finite-size effects, and the breakdown of hydrodynamic scale separation, which bound the correlation length, we demonstrate that the QCD contribution to bulk viscosity can rival the electroweak contribution in realistic conditions. Thus, critical dynamics could leave observable imprints on the hydrodynamic evolution of neutron star mergers.
Comments:
7 pages, 3 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.13474 [pdf]
2 citations
06
[Submitted on 14 Mar 2026] (cross-list from hep-ph)
New nonet scalar mesons and glueballs: the mass spectra and the production yields in relativistic heavy ion collisions
Shigehiro Yasui · Su Houng Lee · Pok Man Lo · Chihiro Sasaki
We propose a new nonet scheme for scalar mesons consisting of $f_{0} (980)$ , $a_{0} (980)$ , $K_{0}^{*} (1430)$ , and $f_{0} (1770)$ , regarding them as quark-antiquark $P$ -wave states classified by $SU (3)$ light flavor symmetry. We investigate their production in relativistic heavy ion collisions, and estimate their yields by applying the statistical model and the quark coalescence model. In contrast to these scalar mesons, we regard $f_{0} (1500)$ as a glueball that is not included in the proposed nonet. We quantify the production yields of $f_{0} (1500)$ by accounting for various internal structures of this state, and compare their yields with those of the new nonet scalar mesons. Given the production yields of these hadrons, our results strongly suggests that $f_{0} (1500)$ is a glueball.
Comments:
11 pages, 6 figures, 6 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.13764 [pdf]
3 citations
07
[Submitted on 14 Mar 2026] (cross-list from hep-ph)
Electromagnetic structure of Bc and heavy quarkonia in the light-front quark model
Rayn Rasyid Harjapradipta🇮🇩 · Muhammad Ridwan🇬🇧 · Ahmad Jafar Arifi🇯🇵 · Terry Mart🇮🇩
We investigate the electromagnetic structure of heavy quarkonia and the $B_{c}$ meson within the light-front quark model (LFQM) to better understand the internal spatial charge distributions and QCD dynamics of heavy mesons. The light-front wave functions (LFWFs) are obtained using a variational approach with a few set of harmonic oscillator basis functions, providing a flexible yet tractable description of the bound-state dynamics. Using these LFWFs, we compute the electromagnetic form factors and compare our results with available lattice QCD data and other model calculations. Our results are roughly consistent with previous model predictions, showing that the electromagnetic radii of the $2 S$ and $3 S$ states are approximately 1.5 times and 1.9 times larger than those of their corresponding $1 S$ states, reflecting the expected growth of spatial size in radial excitations.
Comments:
Accepted in Modern Physics Letters A, 13 pages, 6 figures Contributed to the 1st Southeast Asian Workshop on Nuclear and Hadron Physics (SEA-HNP)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.13819 [pdf]
2 citations
08
[Submitted on 16 Mar 2026] (cross-list from hep-ph)
Small-x TMD distributions initial condition: Nc-dependence and Gaussian approximations
Florian Cougoulic🇵🇱 · Piotr Korcyl🇵🇱 · Tomasz Stebel🇵🇱
We systematically derive expressions for ten small- $x$ Transverse Momentum Dependent (TMD) distributions in the Gaussian approximation, three in the quark-gluon sector and seven in the gluon-gluon sector; for the general $S U (N_{c})$ gauge group. The derived formulae depend on the logarithm of the dipole amplitude. Using the McLerran-Venugopalan model for the initial condition, we simulate the dipole amplitude as well as estimate all ten TMD distributions for $N_{c} \in {2, 3, 4, 5}$ . We compare these explicit numerical results with the derived expressions and find very good agreement for all studied values of $N_{c}$ . Consequently, we study the scaling with $N_{c}$ of the TMD distributions. Thanks to that, we are able to derive the large- $N_{c}$ limit of the Gaussian approximation results and show that they agree with expressions obtained in the mean-field approximation. By comparing with our numerical results, we are able to demonstrate the size, origin, and significance of subleading- $N_{c}$ corrections. This work sets the stage for a systematic study of subleading corrections induced by the JIMWLK evolution in the rapidity evolution of the TMD distributions. Interestingly, we find an exact sum rule that relates all seven gluon-gluon TMD operators at $N_{c} = 3$ and arbitrary $x$ .
Comments:
48 pages, 1 table, 12 figures, version accepted to JHEP
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.15243 [pdf]
JHEP(2026)·0 citations
09
[Submitted on 16 Mar 2026] (cross-list from quant-ph)
Exclusive Scattering Channels from Entanglement Structure in Real-Time Simulations
Nikita A. Zemlevskiy🇺🇸
A scattering event in a quantum field theory is a coherent superposition of all processes consistent with its symmetries and kinematics. While real-time simulations have progressed toward resolving individual channels, existing approaches rely on knowledge of the asymptotic particle wavefunctions. This work introduces an experimentally inspired method to isolate scattering channels in Matrix Product State simulations based on the entanglement structure of the late-time wavefunction. Schmidt decompositions at spatial bipartitions of the post-scattering state identify elastic and inelastic contributions, enabling deterministic detection of outgoing particles of specific species. This method may be used in settings beyond scattering and is applied to detect heavy particles produced in a collision in the one-dimensional Ising field theory. Natural extensions to quantum simulations of other systems and higher-order processes are discussed.
Comments:
17 pages, 8 figures, 6 tables, comments welcome
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.15621 [pdf]
3 citations

Affiliations

first authorsco-authorsvia INSPIRE