Nuclear Theory·nucl-th

Tuesday·January 6, 2026

11 papers—5 primary·6 cross-listed

06
[Submitted on 4 Jan 2026] (cross-list from hep-ph)
Investigating $Ω ϕ$ Interaction and Correlation Functions
Ye Yan · Yuheng Wu · Yue Tan · Qi Huang · Hongxia Huang · Jialun Ping
In this work, we investigate the interaction between the $Ω$ baryon and the $s s ˉ$ meson within the framework of the quark delocalization color screening model. The spectra calculations show that no bound state is formed in any of the considered channels, while the scattering indicates that the $Ω ϕ$ interaction with $J^{P} = 1/ 2^{-}$ is weakly attractive. As for the $Ω ϕ$ interactions with $J^{P} = 3/ 2^{-}$ and $5/ 2^{-}$ , as well as the $Ω η^{'}$ interaction with $J^{P} = 3/ 2^{-}$ , they are all repulsive. After an investigation on the femtoscopic correlation functions, we find that, due to the spin-averaging effect, the overall $Ω ϕ$ correlation function exhibits a weak dependence on the source size, which provides a crucial significance of our model for future experimental examinations in relativistic heavy-ion collisions.
Comments:
10 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2601.01338 [pdf]
PRC(2026)·3 citations
07
[Submitted on 4 Jan 2026] (cross-list from astro-ph.HE)
Binary neutron star mergers with SPHINCS_BSSN: temperature-dependent equations of state and damping of constraint violations
Bhaskar Biswas🇩🇪 · Stephan Rosswog🇩🇪 · Peter Diener🇺🇸 · Lukas Schnabel🇩🇪
Neutron star mergers hold the key to several grand challenges of contemporary (astro-)physics. In view of the upcoming next generation of ground-based detectors, it is crucial to keep improving theoretical predictions to harvest the full scientific returns from these investments. We introduce here a substantial update of our Lagrangian numerical relativity code SPHINCS_BSSN. Apart from changing our unit system, we add constraint damping terms to the BSSN spacetime evolution equations. We demonstrate that this measure reduces, without noteworthy computational cost, the Hamiltonian constraint violations by more than an order of magnitude. We further implement contributions to thermal energy and pressure that are based on Fermi liquid theory and contain a parametrization of the Dirac effective mass. These terms can be combined with any cold equation of state, and they enhance the physical realism of our simulations and introduce a physics-based concept of a temperature. In a set of merger simulations, we demonstrate good agreement with other temperature-dependent numerical relativity simulations. We find that different parametrizations of the Dirac effective mass can translate into shifts of $\sim 150$ Hz in the dominant post-merger gravitational wave peak frequency.
Comments:
20 pages, 14 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2601.01402 [pdf]
6 citations
08
[Submitted on 4 Jan 2026] (cross-list from hep-th)
Gaussian fluctuating Generally covariant diffusion
David Montenegro🇧🇷 · Giorgio Torrieri🇧🇷
We extend the previously developed [1] generally covariant formalism to include diffusion of conserved charges, and comment on the seming difference between the chemica potential term and the diffusion term
Comments:
Extensively extended discussion and apprendix added. Coauthor added. Version accepted, Phys Rev D https://doi.org/10.1103/9bg6-shp6
Subjects:
High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.01656 [pdf]
PRD(2026)·2 citations
09
[Submitted on 5 Jan 2026] (cross-list from hep-th)
Entanglement Viscosity: from Unitarity to Irreversibility in Accelerated Frames
G. Yu. Prokhorov🇷🇺
We demonstrate that the unitarity of quantum field theory, through the positivity of spectral functions, underlies thermodynamic irreversibility for a subsystem separated by a horizon, in direct analogy with the irreversibility of renormalization-group flows. To this end, we explicitly find the shear and bulk viscosities -- the entanglement viscosities -- for thermal radiation in Rindler space using the universal spectral representation. A direct consequence of the obtained general formulas is the relationship between the acceleration-induced shear viscosity in flat space and the conformal quantum anomaly in curved space, pointing to a possible novel probe of the conformal anomaly in systems with extreme acceleration. Moreover, for conformal field theories, we explicitly show that globally entanglement viscosity saturates the Kovtun-Son-Starinets bound.
Comments:
6 pages
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.02083 [pdf]
PRD(2026)·4 citations
10
[Submitted on 5 Jan 2026] (cross-list from hep-ph)
Anti-collinear resummation in JIMWLK evolution in the linear regime
Alex Kovner🇺🇸 · Michael Lublinsky🇮🇱 · Maxim Nefedov🇮🇱 · Vladimir Skokov🇺🇸
The recently-proposed resummation procedure for anti-collinear logarithms in the JIMWLK kernel~\cite{Kovner:2023vsy} is studied in the linear (BFKL) regime in the fixed-coupling approximation. Simple closed form expressions for the resummed momentum space kernel and characteristic function $χ (n, γ)$ are found. We find that the anti-collinear pole in the leading order characteristic function at $γ = 1$ disappears, and instead $χ (γ = 1) = \frac{12}{11} \frac{π}{α _{s} N _{c}}$ for $n_{F} = 0$ . Comparison with the known NLO BFKL eigenvalue, with the target-Bjorken limit ( $Q_{T} ≫ Q_{P}$ ) of the $γ^{*} (Q_{P}) + γ^{*} (Q_{T})$ -scattering amplitude and with the ``all-poles'' resummation prescription are presented.
Comments:
48 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2601.02131 [pdf]
JHEP(2026)·1 citation
11
[Submitted on 5 Jan 2026] (cross-list from physics.atom-ph)
Resolution of the hyperfine puzzle and its significance for two fermion Dirac atoms
Gordon Baym · Glennys Farrar
The hyperfine interaction in the ground state of a hydrogen atom of assumed radius $R$ is proportional to $- 1/ R^{3}$ , raising the question of why the hyperfine interaction does not lead to collapse of hydrogen, or positronium. We approach the problem in terms of a minimax variational calculation based on the exact Gordon solution of the Dirac equation for the hydrogen atom ground state. The full Dirac treatment leads to the result that in an assumed variational state of size $R$ , when $R$ minimizes the total energy the magnetic moment of the electron assumes its usual value, $e ℏ/2 m c$ , but when $R < ℏ/ m c$ , the effective electron magnetic moment becomes essentially $e R /2$ , softening the hyperfine interaction and eliminating an energy minumum at small $R$ . The magnetic moment of the proton is similarly suppressed, and the hyperfine interaction of a small size atom becomes bounded by the kinetic energy, thus assuring stability. We extend the Dirac variational calculation to positronium where we find simple results for the ground state energy and hyperfiine interaction, and then extend this variational calculation to Coulombic atoms of two fermions of arbitrary masses. This paper also lays out a framework for treating diquarks as relativistic Coulombic systems, in the presence of color electric and magnetic interactions.
Comments:
10 pages, one figure
Subjects:
Atomic Physics (physics.atom-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2601.02300 [pdf]
PRA(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Investigating Ωϕ Interaction and Correlation Functions

Binary neutron star mergers with SPHINCS_BSSN: temperature-dependent equations of state and damping of constraint violations

Gaussian fluctuating Generally covariant diffusion

Entanglement Viscosity: from Unitarity to Irreversibility in Accelerated Frames

Anti-collinear resummation in JIMWLK evolution in the linear regime

Resolution of the hyperfine puzzle and its significance for two fermion Dirac atoms

Affiliations

Investigating $Ω ϕ$ Interaction and Correlation Functions