Nuclear Theory·nucl-th

Monday·September 22, 2025

11 papers—6 primary·5 cross-listed

07
Dynamics of quantized vortices under quasi-periodic boundary conditions
Fabio Magistrelli🇩🇪 · Marco Antonelli🇫🇷
The Gross-Pitaevskii equation is widely used for vortex dynamics, but finite domains with hard walls or confining potentials distort bulk behavior through vortex-image effects or induced flows. Periodic boundaries reduce wall artifacts yet cannot realize finite net vorticity because of topological obstruction, so bulk simulations with non-zero circulation are typically unavailable. Hence, we impose quasi-periodic boundary conditions that keep the superfluid's density periodic while enforcing phase windings consistent with a net prescribed total vorticity. This setting conserves the net number of vortices and enables long-time tracking of vortex trajectories in settings that finite containers cannot capture. This allows us to study vortex depinning and nucleation leading to the creation of Kármán vortex streets and perfectly periodic vortex arrays. The framework also provides a toy model for studying vortex dynamics in the bulk of neutron stars, free of possible limitations induced by confining potentials.
↳ cond-mat.quant-gasastro-ph.HEnucl-thPRA(2026)·1 citation
08
Neutron star evolution with the Bemfica-Disconzi-Noronha-Kovtun viscous hydrodynamics framework
Harry L. H. Shum🇬🇧 · Fernando Abalos🇪🇸 · Yago Bea🇪🇸 · Miguel Bezares🇬🇧 · Pau Figueras🇬🇧 · Carlos Palenzuela🇪🇸
The recently proposed first-order viscous relativistic hydrodynamics formulation by Bemfica, Disconzi, Noronha, and Kovtun (commonly known as the BDNK formulation) has been shown to be causal, stable, strongly hyperbolic, and thus locally well-posed. It is now a viable new option for modelling out-of-equilibrium effects in fluids, and has attracted wide attention in its potential applications to astrophysical systems. In this work, we present the first non-linear numerical simulation of spherically symmetric neutron stars using the BDNK formulation under the Cowling approximation. Using a simplified equation of state, we show that stable evolutions can be constructed within a restricted parameter space up to the simulation time we explored. From these simulations, we analyse the frequency content of the quasi-normal modes and the decay rate of the fundamental mode. This analysis serves as a first step towards constructing a fully consistent model of neutron stars using the BDNK formulation.
↳ gr-qcastro-ph.HEnucl-thPRD(2026)·11 citations
09
Transition Form-Factor for $η_{Q}$ at NNLO in the strong coupling $α_{s}$ and with all-order $v^{2}$ resummation
Izabela Babiarz🇵🇱 · Chris A. Flett🇫🇷 · Melih A. Ozcelik🇫🇷 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱
In this work, we discuss both relativistic and perturbative QCD corrections to the transition form-factor $F_{η_{Q}} (t_{1}, t_{2})$ for the process $γ^{*} (q_{1}) γ^{*} (q_{2}) \leftrightarrow η_{Q} (P)$ with dependencies on the normalised photon virtualities $t_{1} = q_{1}^{2} / m_{Q}^{2}$ and $t_{2} = q_{2}^{2} / m_{Q}^{2}$ , where $m_{Q}$ is the heavy quark mass. We resum a class of relativistic corrections to all orders in the relativistic parameter $⟨ v^{2} ⟩_{η_{Q}}$ . In addition, we include perturbative QCD corrections up to Next-to-Next-to-Leading Order (NNLO) in the strong coupling constant $α_{s}$ . This involves the computation of two-loop amplitudes with two off-shell photons. We explore three different phenomenological applications of our transition form-factors for the charmonium case. We first study the ratio $∣ F_{η_{c}} (t_{1}, 0) ∣/∣ F_{η_{c}} (0, 0) ∣$ for the single space-like photon case and compare our results with the existing $η_{c}$ measurements from the BaBar collaboration. Secondly, we consider observables for the case of double space-like photons and discuss the impact of the different corrections. The NNLO corrections for this case are presented here for the first time in the literature. Finally, we revisit the decay width $Γ [η_{c} \to γ γ]$ and compare it with the existing PDG value.
↳ hep-phnucl-thEPJC(2025)·4 citations
10
Accessing nucleon transversity with one-point energy correlators
Mei-Sen Gao🇨🇳 · Zhong-Bo Kang🇺🇸 · Wanchen Li🇨🇳 · Ding Yu Shao🇨🇳
We propose a novel probe of the nucleon's transversity distribution, $h_{1}^{q}$ , using the one-point energy correlator (OPEC), an infrared-and-collinear safe jet substructure observable. We demonstrate that in transversely polarized $p^{↑} p$ collisions, the OPEC exhibits a single-spin asymmetry (SSA) with a clean $sin (ϕ_{s} - ϕ_{n})$ angular dependence. This method probes SSA over a much wider kinematic range in the angular scale $θ_{n}$ compared to traditional measurements of hadron transverse momentum~ $j_{⊥}$ , establishing a complementary and systematically distinct channel to study the nucleon's three-dimensional structure at RHIC and the future Electron-Ion Collider.
↳ hep-phhep-exnucl-exnucl-thPRL(2026)·18 citations
11
Hiding in Plain Sight, the electroweak $η_{W}$
Giacomo Cacciapaglia🇫🇷 · Francesco Sannino🇩🇰 · Jessica Turner🇬🇧
The presence of a topological susceptibility in the electroweak sector of the Standard Model implies the existence of a pseudoscalar state in the spectrum, $η_{W}$ . We show that, within the Standard Model, no new particle is required to form this state. We identify the $η_{W}$ state with the CP-odd linear combination of the ground states of hydrogen and antihydrogen atoms.
↳ hep-phhep-thnucl-th4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Dynamics of quantized vortices under quasi-periodic boundary conditions

Neutron star evolution with the Bemfica-Disconzi-Noronha-Kovtun viscous hydrodynamics framework

Transition Form-Factor for ηQ​ at NNLO in the strong coupling αs​ and with all-order v2 resummation

Accessing nucleon transversity with one-point energy correlators

Hiding in Plain Sight, the electroweak ηW​

Affiliations

Transition Form-Factor for $η_{Q}$ at NNLO in the strong coupling $α_{s}$ and with all-order $v^{2}$ resummation

Hiding in Plain Sight, the electroweak $η_{W}$