Nuclear Theory·nucl-th

Tuesday·February 17, 2026

12 papers—5 primary·7 cross-listed

06
[Submitted on 14 Feb 2026] (cross-list from hep-ph)
Probing Rotational Dynamics of Quark Gluon Plasma via Global Vorticity
Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳
The findings on the spin polarization of $Λ$ , $Ξ$ , and $Ω$ hyperons and spin alignment of $K^{* 0}$ , $ϕ$ , and $D^{*+}$ mesons in relativistic heavy-ion collision experiments at the RHIC and LHC facilities propose the emergence of a strong vorticity field produced in these collisions. Contemplating the potential impact of vorticity on the space-time evolution of deconfined QCD matter and its freeze-out properties, we aim to investigate its characteristics within the medium. We introduce a complementary and data-driven approach to quantify the global vorticity field by extracting it directly from the transverse momentum spectra of produced hadrons. Employing the experimental data for $Λ$ , $Ξ$ , $Ω$ , $K^{* 0}$ , $K^{*\pm}$ , $ϕ$ , $ρ$ , and $D^{*+}$ at mid-rapidity in Au+Au and Pb+Pb collisions over a wide range of beam energies, $s_{NN} = 7.7$ GeV-5.02 TeV, and centrality classes, we systematically examine spin-vorticity coupling in the medium. Our finding on the magnitude of the extracted vorticity is consistent with values deduced from $Λ$ and $Λ ˉ$ polarization measurements using statistical thermal models under the non-relativistic limit. Notably, we observe a prominent particle-species dependence of the vorticity, as well as a non-trivial variation with collision centrality and beam energy. These results indicate that vorticity-driven spin phenomena are sensitive to hadron structure and freeze-out dynamics, providing new constraints on the rotational properties of the QCD matter.
Comments:
Same as the published version in Phys. Letts. B. For supplementary materials, please see the online link using the journal DOI
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2602.13618 [pdf]
PLB(2026)·0 citations
07
[Submitted on 15 Feb 2026] (cross-list from quant-ph)
Non-Hermitian Quantum Mechanics of Open Quantum Systems: Revisiting The One-Body Problem
Naomichi Hatano · Gonzalo Ordonez
We review analyses of open quantum systems. We show how non-Hermiticity arises in an open quantum system with an infinite environment, focusing on the one-body problem. One of the reasons for taking the present approach is that we can solve the problem completely, making it easier to see the structures of problems involving open quantum systems. We show that this results in the discovery of a new complete set, which is one of the main topics of the present article. Another reason for focusing on the one-body problem is that the theory permits the strong coupling between the system and the environment. In the current research landscape, it is valuable to revisit the one-body problem for open quantum systems, which can be solved accurately for arbitrary strengths of the system-environment couplings. A rigorous understanding of the problem structures in the present approach will be helpful when we tackle problems with many-body interactions. First, we consider potential scattering and directly define the resonant state as an eigenstate of the Schrödinger equation under the Siegert outgoing boundary condition. We show that the resonant eigenstate can have a complex energy eigenvalue, even though the Hamiltonian is seemingly Hermitian. Second, we introduce the Feshbach formalism, which eliminates the infinite degrees of freedom of the environment and represents its effect as a complex potential. The resulting effective Hamiltonian is explicitly non-Hermitian. By unifying these two ways of defining resonant states, we obtain a new complete set of bases for the scattering problem that contains all discrete eigenstates, including resonant states. We finally mention the non-Markovian dynamics of open quantum systems. We emphasize the time-reversal symmetry of the dynamics that continuously connects the past and the future. We can capture it using the new complete set that we develop here.
Comments:
41 pages, 25 figures, a review article
Subjects:
Quantum Physics (quant-ph); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
2602.14105 [pdf]
2 citations
08
[Submitted on 15 Feb 2026] (cross-list from quant-ph)
Approximating the $S$ matrix for solving the Marchenko equation: the case of channels with different thresholds
N. A. Khokhlov🇷🇺
This work extends previous results on the inverse scattering problem within the framework of Marchenko theory (fixed- $l$ inversion). In particular, I approximate an $n$ -channel $S$ -matrix as a function of the first-channel momentum $q$ by a sum of a rational term and a truncated sinc series for each matrix element. Relativistic kinematics are taken into account through the correct momentum-energy relation, and the necessary minor generalization of Marchenko theory is given. For energies where only a subset of scattering channels is open, the analytic structure of the $S$ -matrix is analyzed. I demonstrate that the submatrix corresponding to closed channels, particularly near their thresholds, can be reconstructed from the experimentally accessible submatrix of open channels.The convergence of the proposed method is verified by applying it to data generated from a direct solution of the scattering problem for a known potential, and comparing the reconstructed potential with the original one. Finally, the method is applied to the analysis of $S_{31}$ $π N$ scattering data.
Comments:
14 pages, 6 figures
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2602.14150 [pdf]
PRC(2026)·0 citations
09
[Submitted on 16 Feb 2026] (cross-list from astro-ph.HE)
Estimation of neutron star mass and radius of FRB 20240114A by identification of crustal oscillations
Hajime Sotani · Zorawar Wadiasingh · Cecilia Chirenti
By identifying quasi-periodic oscillations (QPOs) reported in FRB 20240114A (from the Five-hundred-meter Aperture Spherical Telescope) with neutron star crustal torsional oscillations, together with experimental constraints on the incompressibility $K_{0}$ of symmetric nuclear matter at saturation density, we constrain the mass and radius of an extragalactic neutron star at redshift $z \approx 0.13$ . Identifying the low-order QPO frequencies as fundamental oscillations, and frequencies of $567.7 Hz$ or $655.5 Hz$ (rest frame) as first overtone candidates, implies neutron star mass ranges of $1.00$ -- $1.55 M_{⊙}$ or $1.17$ -- $1.76 M_{⊙}$ , respectively. The radius is also constrained, with a self-consistent value around $13$ ~km, consistent with the calculation of the NS structure within the low-mass/low-central density regime. Simultaneously, we also constrain another nuclear saturation parameter, namely the density dependence of the nuclear symmetry energy at saturation density (i.e., the slope parameter), $L$ , and determine it to be $L = 59.5 - 96.8$ MeV with $\sim 10%$ systematic uncertainty, which is broadly consistent with previous constraints on $L$ obtained from experiments and astronomical observations. Thus, a mapping of FRB QPOs to crustal torsional modes seems reasonable. This interpretation will be tested with the discovery of additional QPOs in upcoming FRB surveys.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2602.14353 [pdf]
ApJL(2026)·2 citations
10
[Submitted on 16 Feb 2026] (cross-list from astro-ph.HE)
Effects of the symmetry energy slope on magnetized neutron stars
Luiz L. Lopes🇧🇷 · Cesar V. Flores🇧🇷 · Débora P. Menezes🇧🇷
In this work, we study the effect of the symmetry slope on the observables of weakly and strongly magnetized neutron stars within the chaotic magnetic field approximation. We investigate the impact of the symmetry energy slope in the equation of state, as well as on the observables of neutron stars, by calculating their masses, radii, redshifts, tidal deformabilities, and fundamental-mode gravitational-wave frequencies. We show that the effect of the magnetic field is strong on low mass stars, producing a softer equation of state and correspondingly lower values of radii. Furthermore, the magnetic field also causes a significant drop in the dimensionless tidal parameter even when the effects on the radii are small. At the end of the paper, we discuss the effects of the magnetic field in neutron stars' universal relations.
Comments:
15 pages, 4 Figures, open access
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2602.14359 [pdf]
Universe(2026)·0 citations
11
[Submitted on 16 Feb 2026] (cross-list from gr-qc)
The initial data of effective field theories of relativistic viscous fluids and gravity
Lorenzo Gavassino🇬🇧 · Áron D. Kovács🇬🇧 · Harvey S. Reall🇬🇧
There has been recent progress in developing well-posed theories of relativistic viscous hydrodynamics and of gravitational effective field theories. These have in common the feature that they introduce unphysical degrees of freedom. We address the problem of how these should be treated. We propose a ''reduction of order'' approach which is applied not at the level of equations of motion but only to initial data. This specifies uniquely the data for the unphysical modes in terms of the data for the physical modes. We argue that the apparent breaking of Lorentz invariance associated with this approach is not a problem provided one restricts to Lorentz frames for which the assumptions of effective field theory are manifestly valid.
Comments:
13 pages, 2 figures, published in PRD (see https://journals.aps.org/prd/abstract/10.1103/ft2b-m8hv)
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2602.14541 [pdf]
PRD(2026)·7 citations
12
[Submitted on 16 Feb 2026] (cross-list from hep-ph)
Inclusive hadroproduction of $χ_{c 1} (3872)$ , $X_{b}$ and pentaquarks
Nora Brambilla🇩🇪 · Mathias Butenschoen🇩🇪 · Simon Hibler🇩🇪 · Abhishek Mohapatra🇩🇪 · Antonio Vairo🇩🇪 · Xiangpeng Wang🇨🇳
We use the Born--Oppenheimer effective field theory factorization to compute the inclusive production cross sections of the $χ_{c 1} (3872)$ and its partner in the bottomonium sector. In the same framework, we compute the production cross sections of the pentaquark states $P_{c c ˉ} (4312)^{+}$ , $P_{c c ˉ} (4457)^{+}$ , $P_{c c ˉ} (4380)^{+}$ and $P_{c c ˉ} (4440)^{+}$ within two possible scenarios for the Born--Oppenheimer potentials. Also for pentaquarks, we extend the results to the bottomonium sector. All our results are genuine predictions that do not involve fits to prompt hadroproduction data.
Comments:
32 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2602.14916 [pdf]
JHEP(2026)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

Probing Rotational Dynamics of Quark Gluon Plasma via Global Vorticity

Non-Hermitian Quantum Mechanics of Open Quantum Systems: Revisiting The One-Body Problem

Approximating the S matrix for solving the Marchenko equation: the case of channels with different thresholds

Estimation of neutron star mass and radius of FRB 20240114A by identification of crustal oscillations

Effects of the symmetry energy slope on magnetized neutron stars

The initial data of effective field theories of relativistic viscous fluids and gravity

Inclusive hadroproduction of χc1​(3872), Xb​ and pentaquarks

Affiliations

Approximating the $S$ matrix for solving the Marchenko equation: the case of channels with different thresholds

Inclusive hadroproduction of $χ_{c 1} (3872)$ , $X_{b}$ and pentaquarks