Nuclear Theory·nucl-th

Wednesday·July 1, 2026

14 papers—8 primary·6 cross-listed

09
$Λ Λ ˉ$ spin correlations in high-energy collisions from quantum channels: an open quantum system view of hadronization
João Barata🇨🇭 · Iván Cuntín🇨🇭 · Enrique Rico🇨🇭 · Bin Wu🇪🇸
We construct a quantum information-centered approach to describe the experimentally observed behavior of hyperon spin-pair correlations in high-energy collider experiments. The evolution of the spin density matrix of the hyperon pair is treated in the language of quantum channels, accounting both for the spin dynamics in $C^{2} \otimes C^{2}$ and for the pair's angular separation $Δ R$ . We show that the experimental data are consistent with an evolution under a two-qubit depolarizing channel, from which a Lindblad master equation is derived. This provides an open quantum system picture of spin dynamics during the hadronization transition, which is not naturally captured by other quantum channels, and we discuss its microscopic origins. These results show that quantum information science can offer new insights into confinement dynamics beyond the classification of entanglement in the final particle states.
↳ hep-phnucl-thquant-ph1 citation
10
Extraction of the nucleon axial form factor from Lattice QCD using NNLO chiral perturbation theory
Fernando Alvarado🇩🇪 · Luis Alvarez-Ruso🇪🇸
We calculate the nucleon axial form factor in relativistic chiral perturbation theory with $Δ (1232)$ up to next-to-next-to-leading order (NNLO). Relevant low-energy constants are determined by fitting to recent lattice-QCD results at several pion masses, while accounting for the uncertainty associated with the truncation of the chiral expansion. We obtain a good description of the lattice data for momentum transfers up to $Q^{2} ≃ 0.6$ GeV and pion masses up to $M_{π} ≃ 400$ MeV. We find that the explicit inclusion of the $Δ$ resonance is required to reproduce the lattice-QCD pion-mass dependence of the axial charge and axial radius, as well as the momentum dependence of the form factor. At the physical point we obtain $g_{A} = 1.257 \pm 0.011$ and $⟨ r_{A}^{2} ⟩ = 0.312 \pm 0.037 fm^{2}$ . Our analysis provides a model-independent and systematically improvable parametrization of the pion-mass and momentum dependence of the axial form factor, offering a framework for extrapolating lattice-QCD results to the physical point and for improving predictions of low-energy weak interactions involving nucleons.
↳ hep-phhep-exhep-latnucl-th1 citation
11
LUNAR: a Monte Carlo generator for bound-nucleon decay in liquid argon
Jaroslaw Nowak🇬🇧
The search for nucleon decay in liquid-argon time-projection chambers requires a quantitative description of how the bound nuclear environment reshapes the decay-product kinematics. We present LUNAR, a fast, openly available Monte Carlo generator dedicated to two-body decays of protons and neutrons bound in argon-40, the target nucleus of the DUNE far detector. The parent nucleon is drawn from a selectable nuclear ground state -- ten momentum distributions ranging from mean-field Fermi gases to argon spectral functions -- and bound off the mass shell by one of three removal-energy prescriptions, including the momentum-dependent optical potential of Juszczak \textit{et al}. The two-body decay is performed off-shell and boosted to the laboratory frame, and the daughter meson is then propagated out of the nucleus by a semi-classical intranuclear cascade with an optional formation zone for the freshly produced meson. We use the generator to separate the distinct roles of Fermi motion and binding in shaping the observable meson spectrum, to quantify final-state interactions channel by channel, and to translate present Super-Kamiokande limits into expected DUNE event yields for the full set of standard decay modes. Final-state interactions leave the supersymmetry-favored $p \to K^{+} ν ˉ$ signal essentially intact while roughly halving the pion, $η$ , and antikaon rates -- an effect that dominates over the $\pm 10%$ spread induced by the choice of nuclear model. The code is released to the community as a lightweight, extensible tool for signal efficiency and systematics studies.
↳ hep-phnucl-th2 citations
12
FRG analysis of dense two-color QCD within the linear sigma model
Gergely Fejős🇭🇺 · Daiki Suenaga🇯🇵
We investigate the phase structure, hadron masses, and topological susceptibility in the two-flavor and two-color QCD (QC $_{2}$ D) medium, particularly focusing on the $U (1)_{A}$ axial anomaly effects. To this end, we employ the linear sigma model, and hadron fluctuations are incorporated through the functional renormalization group method. We establish in detail an effective potential that respects symmetries of QC $_{2}$ D at finite quark chemical potential, $μ_{q}$ : $S U (2)_{L} \times S U (2)_{R}$ chiral, $U (1)$ baryon-number, parity and time-reversal symmetries. We find that the $U (1)_{A}$ anomaly couplings for mesons at finite temperature are enhanced with increasing $μ_{q}$ , while that of the baryons are not too sensitive to $μ_{q}$ . Despite the anomaly enhancement, we find that the topological susceptibility at larger $μ_{q}$ is always suppressed regardless of the temperature, following chiral restoration. We also find that mass degeneracies of the chiral partners are well realized at higher temperatures and densities by the chiral restoration. Our findings are expected to provide useful information on properties of the $U (1)_{A}$ anomaly in medium for sign-problem-free lattice simulations of QC $_{2}$ D.
↳ hep-phhep-latnucl-th1 citation
13
Hadronic exceptional points
Ahmad Jafar Arifi🇯🇵 · Kei Suzuki🇯🇵
Exceptional points, where eigenvalues and eigenvectors coalesce, are a defining feature of non-Hermitian systems and have been extensively observed in photonic, atomic, and condensed matter systems. However, they have received little attention in quantum chromodynamics (QCD), which is the fundamental theory of quarks, gluons, and hadrons. We propose that imaginary magnetic fields provide a simple realization of non-Hermitian dynamics in hadronic systems. Based on two theoretical approaches, a hadronic effective Lagrangian and a constituent quark model, we compute mass spectra of neutral mesons and find exceptional points separating the real-spectrum and complex-eigenvalue regimes. In small fields, the real spectrum exhibits level attraction between hadronic states, whereas in larger fields, hadrons are deconfined, which is a signature of a field-induced inverted potential. Our findings open a new avenue for studying QCD dynamics in non-Hermitian environments.
↳ hep-phhep-lathep-thnucl-th+10 citations
14
Finite-Density Dynamics of Chemically Equilibrating QGP in Conformal Gubser Flow and Hard Thermal Photon Production
Lakshmi J. Naik🇮🇳 · V. Sreekanth🇮🇳
We study the chemical equilibration of a hot and dense quark-gluon plasma (QGP) at finite baryon density produced in relativistic heavy-ion collisions within conformal Gubser flow. Chemical non-equilibrium is incorporated through fugacity parameters in the parton phase-space distribution functions, whose evolution is governed by master rate equations coupled to the hydrodynamic expansion with transverse flow. We analyse the interplay between chemical equilibration and finite-density dynamics, and investigate its impact on hard thermal photon production. We observe that both finite density and transverse expansion delay chemical equilibration, leading to a chemically undersaturated medium with quarks lagging behind gluons. While the overall thermal photon yield from the expanding system is suppressed in the non-equilibrium scenario, we find an enhanced early-time contribution to high $p_{T}$ photon production. By analyzing the instantaneous photon emission in presence of chemical non-equilibrium, we demonstrate that the rates exhibit a distinct temporal structure arising from the interplay of rapid cooling and evolving fugacities. These features may provide potential observable signatures of chemical equilibration dynamics in the QGP.
↳ hep-phnucl-thJ.Phys.G(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

ΛΛˉ spin correlations in high-energy collisions from quantum channels: an open quantum system view of hadronization

Extraction of the nucleon axial form factor from Lattice QCD using NNLO chiral perturbation theory

LUNAR: a Monte Carlo generator for bound-nucleon decay in liquid argon

FRG analysis of dense two-color QCD within the linear sigma model

Hadronic exceptional points

Finite-Density Dynamics of Chemically Equilibrating QGP in Conformal Gubser Flow and Hard Thermal Photon Production

Affiliations

$Λ Λ ˉ$ spin correlations in high-energy collisions from quantum channels: an open quantum system view of hadronization