Nuclear Theory·nucl-th

Thursday·April 23, 2026

11 papers—5 primary·6 cross-listed

01
[Submitted on 22 Apr 2026]
A Poincaré-covariant study of strange quark stars
Hao-Ran Zhang · Bo-Lin Li🇨🇳 · Zhu-Fang Cui🇨🇳
We investigate the properties of dense quark matter and strange quark stars within a nonperturbative, Poincaré-covariant framework. Employing a symmetry-preserving vector $\otimes$ vector contact interaction model, we extend the quark gap equation to the regime of zero temperature and finite quark chemical potential. From the resulting momentum-independent quark propagator, we construct the equation of state (EOS) and solve the Tolman-Oppenheimer-Volkoff (TOV) equations to evaluate the mass-radius relations and tidal deformabilities of strange quark stars. We systematically analyze the sensitivity of the EOS and the macroscopic stellar properties to the model parameters, specifically the effective interaction strength and the ultraviolet cutoff. We demonstrate that reducing the coupling constant stiffens the EOS, whereas increasing the ultraviolet cutoff softens it. By confronting our predictions with multi-messenger astrophysical constraints-including pulsar mass measurements and gravitational-wave data-we identify parameter regimes that successfully describe current observations. Specifically, we find that parameter sets with $α_{i r} = 0.735 π$ , $Λ_{uv} = 0.905 GeV$ and $α_{i r} = 0.588 π$ , $Λ_{uv} = 0.9955 GeV$ , alongside a vacuum bag pressure of $B \approx (0.106 GeV)^{4}$ , yield stellar properties in excellent agreement with empirical constraints.
Comments:
8 pages, 6 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2604.20159 [pdf]
0 citations
02
[Submitted on 22 Apr 2026]
Investigation of Nonlinear Collective Dynamics in Relativistic Heavy-Ion Collisions Using A Multi-Phase Transport Model
Zhi-Jie Yang🇨🇳 · Hao-jie Xu🇨🇳 · Jie Zhao🇨🇳 · Hanlin Li🇨🇳
The nonlinear response coefficient, $χ_{4, 22}$ , is a crucial observable for probing the dynamical properties of the quark-gluon plasma (QGP). While traditionally understood as a signature of medium response, recent studies suggest that $χ_{4, 22}$ also encapsulates critical information regarding the intrinsic initial-state configuration of the colliding nuclei. In this study, we utilize A Multi-Phase Transport (AMPT) model to investigate the microscopic origin and stage-by-stage development of $χ_{4, 22}$ in $^{238}$ U+ $^{238}$ U and $^{197}$ Au+ $^{197}$ Au collisions at $s_{NN} = 200$ GeV. By tracking the flow observables through the partonic cascade, quark coalescence, and hadronic rescattering phases, we map the translation of initial geometric eccentricities into final-state momentum anisotropies. Our results demonstrate that the absolute magnitude of $χ_{4, 22}$ increases continuously during the collective expansion, confirming its nature as a dynamically generated medium response. However, the comparative ratio of this coefficient between the U+U and Au+Au systems is stable across all evolutionary stages within statistical uncertainties. This indicates that the ratio approximately cancels complex evolutionary dynamics to isolate intrinsic geometric correlations present at the initial state. These findings provide compelling theoretical support and crucial insights for recent experimental efforts aiming to extract high-order nuclear structure, such as hexadecapole deformation, using nonlinear flow observables.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2604.20493 [pdf]
1 citation
03
[Submitted on 22 Apr 2026]
Charged-Current Neutrino-Induced Single-Pion Production in the Superscaling Approach and Relativistic Distorted-Wave Impulse Approximation
Jesus Gonzalez-Rosa🇪🇸 · Alexis Nikolakopoulos🇺🇸 · Maria B. Barbaro🇮🇹 · Juan A. Caballero🇪🇸 · Raúl González-Jiménez🇪🇸 · Guillermo D. Megias🇪🇸
In this work, we present a detailed comparison of the SuSAv2 (SuperScaling Approach version 2) and RDWIA (Relativistic Distorted-Wave Impulse Approximation) models with measurements of charged-current neutrino-induced single-pion production from different experiments (T2K, MINERvA and MiniBooNE), studying the differences between the two theoretical descriptions. The neutrino energy range in these experiments spans from hundreds of MeV to roughly 20 GeV, and the nuclear targets are mainly composed of $^{12}$ C. The SuSAv2 model uses the single-nucleon inelastic structure functions from the ANL-Osaka DCC model, which allows for a separation of pion production channels, distinguishing between the $π^{+}$ , $π^{-}$ and $π^{0}$ final states. In the RDWIA approach, the Hybrid model developed by the Ghent group is used for the description of the boson-pion-nucleon vertex.
Comments:
20 pages, 15 figures, 2 tables. Version accepted for publication in Universe
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
arXiv:
2604.20508 [pdf]
Universe(2026)·1 citation
04
[Submitted on 22 Apr 2026]
Cutoff-independent predictions from nuclear lattice effective field theory
Chen-Can Wang🇨🇳 · Jia-Ai Shi🇨🇳 · Bing-Nan Lu🇨🇳
Cutoff independence is an essential requirement for the predictive power of nuclear \textit{ab initio} calculations based on effective field theory (EFT). While it is conventionally assumed that such invariance necessitates high-order interactions and complex many-body forces, we present a minimal chiral nuclear force that exhibits remarkable cutoff independence across a broad range from light to medium-mass nuclei and sub-saturated nuclear matter. Our framework comprises only contact terms up to next-to-leading order, a single three-nucleon contact force, and a leading-order one-pion-exchange potential, all constrained strictly in the $A \leq 3$ sector. Despite its simplicity, this interaction accurately reproduces experimental binding energies up to $^{40} Ca$ with unexpectedly small residual cutoff dependencies of only a few MeV. We demonstrate that the use of a lattice-inspired \emph{absolute}-momentum regulator efficiently suppresses high-momentum modes, resolving the overbinding problem for soft chiral forces without invoking complex many-body forces. These results establish a robust and economic foundation for EFT-based \textit{ab initio} calculations in both continuum and lattice frameworks.
Comments:
6 pages, 4 figures. Includes supplemental material
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2604.20681 [pdf]
2 citations
05
[Submitted on 22 Apr 2026]
Interaction between nuclear clusters and superfluid phonons in the neutron-star inner crust
Masayuki Matsuo · Arata Nishiwaki · Toshiyuki Okihashi · Masaru Hongo
The interaction between lattice vibrations of nuclear clusters and superfluid phonons associated with neutron superfluidity plays an important role in the dynamics of the neutron-star inner crust. While this coupling has been discussed mainly within macroscopic approaches such as hydrodynamics and effective field theory, its microscopic origin and the value of the effective coupling constant have remained unclear. In this work, we derive the interaction between nuclear clusters and superfluid phonons starting from a microscopic description of inner-crust matter. Using nuclear density functional theory, we analyze the response of a neutron superfluid around a single nuclear cluster within the quasiparticle random-phase approximation. From this microscopic response, we obtain the interaction between the cluster and the surrounding superfluid. Matching this result to the long-wavelength effective description, we determine the coupling constant in an effective Hamiltonian describing the mixing between lattice and superfluid phonons. The resulting coupling strength is found to be significantly smaller than previous hydrodynamical estimates. This reduction originates from the suppression of the superfluid phonon amplitude inside and around the nuclear cluster. Our results provide a microscopic determination of the coupling parameter governing lattice-superfluid phonon mixing in the neutron-star inner crust.
Comments:
16 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2604.20725 [pdf]
0 citations
06
[Submitted on 21 Apr 2026] (cross-list from hep-ph)
A First Account of the Impact of Ion Electromagnetic Dissociation on Event Exclusivity in Ultraperipheral LHC Collisions
M. Dyndal🇵🇱 · L. A. Harland-Lang🇬🇧
In this Letter we explore the modelling of hadron production in electromagnetic ion dissociation (EMD) processes in high-energy ultraperipheral collisions at LHC energies. Since EMD can accompany exclusive particle production in these interactions, we demonstrate that the resulting hadrons can break the exclusivity vetos typically imposed by experiments. As two representative examples, we calculate the impact on existing LHC measurements of exclusive muon pair production ( $γ γ \to μμ$ ) and exclusive coherent $J / ψ$ production. We demonstrate that accounting for this effect resolves long-standing tensions between theoretical predictions and experimental measurements.
Comments:
9 pages, 8 figures, version submitted to journal
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.19879 [pdf]
5 citations
07
[Submitted on 22 Apr 2026] (cross-list from hep-ph)
Impact of nuclear deformation on particle production in $N e + N e$ collisions at \texorpdfstring{\five}{sqrt(sNN)=5.36 TeV} from AMPT-SM
M. U. Ashraf🇺🇸 · A. M. Khan🇺🇸 · M. Shahid🇺🇸 · Faraz Mohd Mehdi🇺🇸
We present a systematic study of particle production in $N e + N e$ collisions at $s_{NN} = 5.36$ TeV using the A Multi-Phase Transport (AMPT) model with string melting (SM) configuration. The analysis compares spherical and deformed configurations of $^{20} Ne$ to investigate the influence of initial-state nuclear deformation on bulk observables. Charged-particle pseudorapidity ( $⟨ d N_{ch} / d η ⟩$ ) densities, identified particle yields ( $d N / d y$ ), transverse momentum ( $p_{T}$ ) spectra, mean transverse momentum ( $⟨ p_{T} ⟩$ ), and $p_{T}$ -differential particle ratios ( $K / π$ and $p / π$ ) are studied as functions of multiplicity and centrality. The results show that all observables exhibit the expected dependence on event activity, including smooth multiplicity scaling, mass ordering in $⟨ p_{T} ⟩$ , and characteristic features associated with radial flow and quark coalescence. Differences between the two configurations on bulk observables remain small across all observables, typically at the level of a 2\%--6\% percent, with slightly enhanced sensitivity observed in peripheral collisions. These findings suggest that, within the AMPT-SM framework, the collective dynamics and hadrochemical composition are primarily governed by the overall system density and interaction dynamics, while the influence of initial-state deformation is subleading. This study provides a baseline for understanding deformation effects in light-ion collision systems and highlights the limited sensitivity of bulk observables to initial nuclear geometry in transport-based approaches.
Comments:
7 pages,7 Figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2604.20152 [pdf]
0 citations
08
[Submitted on 22 Apr 2026] (cross-list from hep-ph)
Chiral first order phase transition at finite baryon density and zero temperature from self-consistent pole masses in the linear sigma model with quarks
Alejandro Ayala🇲🇽 · Bruno El-Bennich🇧🇷 · Ricardo L. S. Farias🇺🇸 · Luis A. Hernández🇲🇽 · Bruno S. Lopes🇺🇸 · Luis C. Parra L.🇲🇽 · Renato Zamora🇨🇱
We use the two-flavor Linear Sigma Model with quarks as an effective description of QCD to investigate the nature of the chiral phase transition at finite baryon chemical potential and zero temperature. We work at one-loop order to set up and solve the system of self-consistent coupled equations for the particle pole masses. The chemical potential-dependent value of the chiral order parameter is obtained by minimizing the one-loop effective potential. This treatment goes beyond the conventional ring-diagram approximation and provides a description valid for arbitrary values of the chemical potential. We find that the phase transition is of first order, and occurs when the quark chemical potential reaches the value of the vacuum quark mass for the chosen set of parameters. The first order nature of the transition is signaled by the discontinuous behavior of the chiral condensate, the masses and the couplings. The thermodynamics of the system is readily implemented and in particular, we find that the square of the speed of sound exhibits a discontinuity at the phase transition and then smoothly approaches the conformal limit from below.
Comments:
12 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2604.20196 [pdf]
PRD(2026)·0 citations
09
[Submitted on 22 Apr 2026] (cross-list from hep-ph)
No planar degeneracy for the Landau gauge quark-gluon vertex
Georg Wieland🇦🇹 · Reinhard Alkofer🇦🇹
Based on a suitable basis system for the quark-gluon vertex' transverse tensor structures and on carefully chosen kinematical variables, the transverse part of the quark-gluon vertex in quenched QCD in the Landau gauge is obtained from a system of Dyson-Schwinger equations. We demonstrate by analysing this solution that the angular dependence of these transverse quark-gluon vertex form factors is seemingly weak. We nevertheless argue that this does not imply a planar degeneracy for this vertex because even this mild dependence cannot be neglected when aiming for reasonably precise results for derived quantities. Last but not least, for a self-consistently coupled systems of 3PI Dyson-Schwinger equations for the quark propagator and the quark-gluon vertex we confirm that the core ingredient to dynamical chiral symmetry breaking is the dynamically generated tensor coupling of glue to quarks which itself is only possible because of chiral symmetry breaking. Furthermore, we find (i) a relation in between the calculated chirality violating vertex form factors; (ii) that the quark propagator is identical within numerical errors when obtained either from a decoupling solution or the scaling solution for the Yang-Mills propagators and vertex functions; and (iii) that the resulting quark propagator is consistent with possessing poles only on the real time-like half-axis. Furthermore, we provide high-precision fits for the form factors based on sometimes astonishingly simple model functions.
Comments:
24 pages, 22 figures, 6 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2604.20235 [pdf]
2 citations
10
[Submitted on 22 Apr 2026] (cross-list from quant-ph)
Rank-2 Electromagnetic Backgrounds and Angular Momentum Barriers in Gravitomagnetic Spin-Quadrupole Searches
Leonardo A. Pachon🇨🇴
We present a complete analysis of the angular momentum selection rules and electromagnetic backgrounds that constrain any spectroscopic search for the gravitomagnetic spin-quadrupole coupling in highly charged ions. A sequence of four barriers is identified: (i)~the Wigner-Eckart theorem mandates $j \geq 3/2$ electronic states for sensitivity to the rank-2 gravitomagnetic operator, excluding the deformation-immune $j = 1/2$ states; (ii)~the nuclear electric quadrupole hyperfine interaction (HFS-E2) generates an $\sim 18$ -orders-of-magnitude electromagnetic background in the required $j = 3/2$ channel; (iii)~second-order HFS mixing between fine-structure levels leaves a residual $\sim 1 0^{- 6}$ eV even after centroid extraction; (iv)~tensor nuclear polarizability (TNP), scaling with $B (E 2)$ rather than $Q_{s}$ , introduces an independent rank-2 background of $\sim 1 0^{- 12}$ eV. We derive the algebraic conditions under which a multi-isotope, multi-transition Generalized King Plot can separate these backgrounds from the gravitational signal, and show that the minimum experimental topology requires three transitions and $N_{odd} \geq N_{bkg} + 1$ odd-spin isotopes with linearly independent nuclear parameters. For the molybdenum chain, this yields a first laboratory-derivable bound $∣ χ - 1∣ ≲ 1 0^{8} - 1 0^{9}$ on the gyrogravitational ratio, limited by current precision on nuclear quadrupole moments and transition rates. We quantify the experimental milestones needed to improve this bound by each order of magnitude, providing a roadmap for future searches.
Comments:
7 pages + Supplementary Information (PDF)
Subjects:
Quantum Physics (quant-ph); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2604.20717 [pdf]
0 citations
11
[Submitted on 22 Apr 2026] (cross-list from hep-ph)
Probing QCD instantons using jet correlation observables in proton-proton collisions at the LHC
Sayak Guin🇮🇳 · Swagatam Tah🇮🇳 · Nihar Ranjan Sahoo🇮🇳 · Sayantan Sharma🇮🇳
Discovery of instantons in colliders will provide experimental evidence for the topological properties of the QCD vacuum. In this work, we propose jet correlation observables that can unambiguously discriminate between instanton-induced processes and perturbative hard scattering events in pp collisions at LHC energies. By calculating the instanton sizes and their separations in 2+1 flavor QCD with physical quark masses, we provide constraints on the center-of-mass energies of the produced hadrons in an instanton-induced process. Our proposal is directly applicable for future ep measurements at the Electron-Ion Collider, offering a cleaner environment to probe instanton-induced processes.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.20780 [pdf]
1 citation

Affiliations

first authorsco-authorsvia INSPIRE