Nuclear Theory·nucl-th

Thursday·April 30, 2026

12 papers—5 primary·7 cross-listed

01
Possible explanation of Hoehler's clustering: effective partial-wave mixing induced by truncation
A. Svarc🇭🇷
Hoehler noted that resonance poles obtained from different partial waves in $π N$ scattering appear to bunch together near a small set of common complex energies, and suggested that this could indicate mixing between angular momenta. Here, we examine whether at least part of this pattern could arise effectively from the extraction procedure itself. Exact partial-wave unitarity preserves the separation of angular momenta in the infinite problem, whereas practical pole extraction from bilinear observables requires truncation of the partial-wave series. Combined with the truncation-induced mixing mechanism established in Ref.~\cite{Svarc2026}, this provides a natural source by which fitted partial-wave coefficients can inherit overlapping pole-bearing content, thereby offering a plausible contribution to Hoehler-type clustering.
nucl-th0 citations
02
Thermal and geometric normal modes of spectral fluctuations in heavy-ion collisions
Rupam Samanta🇵🇱
The transverse momentum spectrum of charged particles in ultra-relativistic heavy-ion collisions fluctuates event-by-event, encoding signatures of underlying collective dynamics. Such fluctuations originate from a combined effect of thermal and geometric fluctuations in the initial state. We present a direct decomposition of these spectral fluctuations through principal component analysis performed on the joint covariance structure of normalized spectrum, mean transverse momentum and elliptic flow squared. The first two leading modes explain 99.5\% of the total variance, and are orthogonally rotated by imposing physical constraints motivated by the initial state thermal and geometric response. The resulting thermal and geometric modes bear direct analogy with the vibrational normal modes of a linear triatomic molecule. The thermal mode entirely drives the experimentally measured $v_{0} (p_{T})$ , while the geometric mode contributes substantially to $v_{02} (p_{T})$ in non-central collisions, providing a transparent explanation of its characteristic low- $p_{T}$ sign change. The study establishes the first physically motivated interpretation of principal component modes in the field of heavy-ion collisions and provides an experimental window into the thermo-geometric structure of the QGP initial state.
nucl-thhep-phnucl-exPLB(2026)·1 citation
03
Effectiveness of nonflow suppression using multi-particle correlators
Chong Ye🇨🇳 · Wei-Liang Qian🇨🇳 · Yue Cui🇧🇷 · Dan Wen🇨🇳 · Yutao Xing🇧🇷 · Rui-Hong Yue🇨🇳 · Takeshi Kodama🇧🇷
As flow estimators, multi-particle correlators, particularly the higher-order ones, are generally regarded as effective tools for suppressing non-flow contributions. In this work, however, using two well-known toy models that simulate non-flow effects, we demonstrate that multi-particle correlators can, especially in small systems, yield estimates that deviate even further from the underlying flow harmonics than those obtained from other conventional approaches. The two toy models considered here are designed to mimic non-flow effects arising from particle decay and global momentum conservation, such that the {\it apparent} harmonic coefficients become significantly different from the {\it input} values. We provide an analytic explanation for the observed behavior of flow estimates based on multi-particle correlators. Specifically, in the toy model mimicking particle decay, we elucidate the oscillations observed in $v_{2} {2}$ and $v_{2} {4}$ . For the other toy model simulating momentum conservation, we show that multi-particle cumulants introduce a deformation in the collective flow that is unique to multi-particle correlators. Additionally, we compare these results with those obtained using the maximum-likelihood estimation method, a recently proposed flow estimator that serves as a viable alternative to traditional techniques.
nucl-th0 citations
04
Neutron Stars and Neutron Skins: Connecting Finite Nuclei to Dense Matter
C.A. Bertulani
This is a brief overview of the connection between neutron skin thickness in finite nuclei and the equation of state of neutron-rich matter, with applications to neutron stars. Multiple experimental probes are discussed, including dipole polarizability, parity-violating electron scattering, heavy-ion fragmentation, quasi-free scattering, and ultraperipheral collisions. A consistent picture emerges from Bayesian analyses combining experimental data and energy density functionals, providing constraints on the symmetry energy and its slope.
nucl-thastro-ph.HEastro-ph.SR0 citations
05
Outer-crust equations of state for neutron stars
P.S. Koliogiannis · N. Paar
The equation of state of the outer crust of neutron stars is sensitive to nuclear mass predictions and provides a direct connection to the properties of nuclei throughout the nuclide map, including those beyond experimental reach. We quantify the impact of contemporary nuclear mass models on the composition and thermodynamic properties of the outer crust and assess the consequences for crust-dominated neutron-star configurations near the minimum-mass limit. We constructed four outer-crust equations of state based on the relativistic energy density functional and machine-learning mass model tables. The equilibrium composition of cold catalysed matter in $β$ -equilibrium was obtained by minimising the Gibbs free energy per nucleon, and the resulting equations of state were implemented in neutron-star structure calculations. The different mass inputs lead to variations in the equilibrium nuclide sequence, distinct last bound nuclei, and moderate shifts in the neutron-drip density. In contrast, the associated thermodynamic properties, as well as the minimum-mass neutron-star configurations, remain closely aligned across the four outer-crust equations of state. The model dependence of the outer crust is primarily reflected in the detailed nuclide composition and in the precise location of neutron drip. Nevertheless, the considered outer-crust equations of state yield closely consistent predictions for the relevant neutron-star observables, providing a reliable input for stellar modelling.
nucl-thastro-ph.HEastro-ph.SR0 citations
06
Resonance Statistics -Informed Fitting Applied to Automated Cross Section Evaluation
William Fritsch · Noah Walton · Justin Loring · Jacob Forbes · Oleksii Zivenko · Aaron Clark · Elan Park-Bernstein · Vladimir Sobes
This work investigates the use of resonance statistics for resonance evaluation to inform spin group assignment and an alternative fitting objective function beyond the commonly used chi-squared statistic. Resonance statistics -informed methods are applied to the automated resonance fitting framework, developed by N. Walton et al. In this automated framework, the utility of resonance statistics is largely unexplored. The new resonance statistics -informed spin group shuffling algorithm reduces spin group frequency bias seen in the base fitting algorithm. Although resonance statistics -informed optimization produces negligible changes in pointwise cross section agreement, it significantly improves consistency with Wigner level-spacing statistics and stabilizes the fitted resonance density in the presence of model imperfections.
↳ physics.comp-phcond-mat.mtrl-scinucl-th0 citations
07
Revisiting Turner Window Axions: The Untapped Potential of NaI Dark Matter Detectors
W. C. Haxton🇺🇸 · Xing Liu🇺🇸 · Anupam Ray🇨🇦 · Evan Rule🇺🇸
The "Turner window" corresponds to axions with masses $≳$ 1 eV that have sufficiently strong couplings to matter to evade limits from the cooling of SN1987A. This window, through which the trajectories for the KSVZ and DFSZ QCD axions run, has been thought to be largely closed because of (1) the floor established by SN1987A cooling, (2) the absence of SN1987A-associated photons in the Kamioka II detector, and (3) the limit on neutrons produced by solar axions in the Sudbury Neutrino Observatory. We show that a more complete treatment of the axion opacity in SN1987A, significantly weakens (2). Consequently, for axion or axion-like particles with hadronic couplings, $g_{ann}$ and $g_{a pp}$ , significant regions within the Turner window now become viable. We describe a new opportunity to constrain such hadronically coupled axions via their resonant absorption in NaI detectors. The source is the Milky Way's carbon-burning stars -- the progenitors of ONeMg white dwarfs as well as electron-capture and core-collapse supernovae -- which synthesize significant quantities of $^{23}$ Na, keeping it at temperatures $\sim 1 0^{9}$ K for periods up to tens of thousands of years. $^{23}$ Na acts as a thermal pump to convert stellar energy into axions, which arrive at the Earth as a thermally broadened line at 440 keV. These axions can be detected via resonant absorption in NaI, with the needed detector arrays already in place, developed by DAMA/LIBRA and other collaborations to search for the elastic scattering of light WIMPs. In axion detection, NaI serves as both the target, producing $γ$ 's following resonant absorption, and the detector for those $γ$ 's. With current array masses and backgrounds, we find that the coupling range $∣ g_{a pp} ∣ \sim 1 0^{- 6.5}$ -- $1 0^{- 2}$ can be covered after two years of data, including QCD axions with $m_{a} ≳ 10$ eV.
↳ hep-phastro-ph.HEhep-exnucl-ex+11 citation
08
Formation of gaseous, doubly charged cerium monofluoride CeF $^{2 +}$ and its sensitivity to new physics
R. Simpson🇨🇦 · C. Zülch🇩🇪 · K. B. Ng🇨🇦 · I. Belosevic🇨🇦 · C. Charles🇨🇦 · P. Justus🇩🇪 · R. Berger🇩🇪 · S. Malbrunot-Ettenauer🇨🇦 · A. A. Kwiatkowski🇨🇦 · M. P. Reiter🇬🇧 · J. Ash🇨🇦 · C. Babcock🇨🇦 and 16 other authors
Tricationic protactinium monofluoride ( $^{229}$ PaF $^{3 +}$ ) has been proposed as a candidate for probing physics beyond the Standard Model of particle physics. Since studies with $^{229}$ PaF $^{3 +}$ require significant experimental advances, we exploit the stable, valence-isoelectronic dicationic cerium monofluoride (CeF $^{2 +}$ ) as a surrogate. Gas-phase fluorinated-cerium molecular ions are formed and identified using the Off-Line Ion Source and TITAN mass measurement facilities at TRIUMF. Quantum chemical calculations are performed on the electronic structure of CeF $^{2 +}$ , revealing a parallel to that of $^{229}$ PaF $^{3 +}$ . Moreover, these calculations provide estimates on the sensitivity of CeF $^{2 +}$ itself to various $P, T$ -odd properties. A brief discourse on the specifics of the quantum control of CeF $^{2 +}$ is presented which anticipates future searches for symmetry violations.
↳ physics.atom-phnucl-exnucl-thquant-ph1 citation
09
Quantum Complexity and New Directions in Nuclear Physics and High-Energy Physics Phenomenology
Caroline E. P. Robin🇩🇪 · Martin J. Savage🇺🇸
Advances in quantum information science (QIS) are providing transformative insights into the complexity of quantum many-body systems, potentially defining new frontiers in nuclear and high-energy physics. This review explores how QIS-derived techniques are fostering new analytic frameworks and algorithms - both classical and quantum - to tackle (some of the) present barriers to discovery in fundamental physics, with applicability to other science domains. We highlight how these techniques are shedding new light on the structure and dynamics of hadrons, nuclei, matter in extreme conditions, and beyond. Importantly, they are expected to play an essential role in the development of large-scale quantum simulations of such systems, particularly in setting the balance among quantum and classical computational resources.
↳ quant-phhep-lathep-phnucl-th15 citations
10
Particle seismology: mechanical and gravitational properties from parton-hadron duality
Enrique Ruiz Arriola🇪🇸 · Wojciech Broniowski🇵🇱
The internal structure of hadrons is characterized by form factors which correspond to matrix elements of currents. Among those, the stress-energy-momentum tensor is a universally conserved quantity providing the gravitational form factors, from which mechanical properties may be derived via the response to the space-time fluctuations. They have received much attention because of their role as moments of the Generalized Parton Distributions, where the stress-energy-momentum tensor couples to two photons, and more recently, due to the explicit lattice QCD determination for the pion and nucleon. In these lectures we attempt a pedagogical review of the topic from a purely hadronic point of view, based on the notion of dispersion relations, meson dominance, and parton-hadron duality. We show that despite the overwhelming simplicity of the approach, a rather successful description of the lattice QCD data is achieved.
↳ hep-phhep-latnucl-th1 citation
11
Thermodynamics of magnetized matter in hot and dense QCD
Bastian B. Brandt🇩🇪 · Gergely Endrodi🇭🇺
This chapter, to appear in the section on QCD under extreme conditions within the Encyclopedia of Nuclear Physics, aims to provide a pedagogical introduction to the physics of quarks and gluons in the presence of high temperature, nonzero (isospin) density and strong background electromagnetic fields. Extreme conditions of these types are relevant for the description of high-energy heavy-ion collisions, neutron stars and their mergers, as well as the evolution of the early Universe in its first microsecond. Most of the existing results on this topic have been obtained by means of first-principles simulations of the discretized theory of the strong interactions, lattice Quantum Chromodynamics (QCD). This lays the focus of this review chapter, although various calculations within effective theories of QCD -- most notably chiral perturbation theory -- are also discussed. Furthermore, we provide an outlook concerning open questions and yet uncharted parameter regions within this fascinating system.
↳ hep-lathep-phnucl-th2 citations
12
Continuum contribution to charged-current absorption of low-energy $ν_{e}$ on $^{40}$ Ar
Steven Gardiner🇺🇸 · Pablo Barham Alzás🇨🇭 · Alexis Nikolakopoulos🇺🇸 · Luca H. Abu El-Haj🇺🇸 · Natalie Jachowicz🇧🇪 · Vishvas Pandey🇺🇸
Accurate modeling of the absorption of tens-of-MeV $ν_{e}$ on $^{40}$ Ar is needed to enable measurements of astrophysical neutrinos using large liquid argon time projection chamber (LArTPC) detectors, such as those planned for the Deep Underground Neutrino Experiment (DUNE). We revisit the MARLEY neutrino interaction model used in present estimates of DUNE sensitivity to supernova and solar neutrino signals. Multiple theoretical refinements are pursued, especially in the unbound continuum region of nuclear excitation energy. Inclusive charged-current neutrino-argon cross sections are calculated using a hybrid strategy. Nuclear transitions to unbound states are treated using a Hartree-Fock Continuum Random Phase Approximation (HF-CRPA) model, including forbidden contributions. Allowed transitions to low-lying discrete levels are also included using indirect measurements and approximate corrections for the momentum transfer dependence. Exclusive predictions are obtained by coupling these calculations with a statistical nuclear de-excitation model. The impact on observables of interest for DUNE and similar experiments is examined in terms of both total and differential cross sections. Our refined calculations predict a lower allowed portion of the cross section relative to the prior MARLEY model. At neutrino energies appreciably below 100 MeV, the inclusion of forbidden transitions does not fully compensate for the loss of allowed strength. For a representative neutrino burst from a galactic core-collapse supernova, our results suggest that MARLEY 1.2.0 overestimates the event yield in a DUNE-like detector by approximately 20%. However, because this overestimation is more severe at backwards angles, use of the charged-current $ν_{e}$ - $^{40}$ Ar reaction for supernova pointing may be more feasible than previously expected.
↳ hep-phnucl-th3 citations

Affiliations

first authorsco-authorsvia INSPIRE