Nuclear Theory·nucl-th

Monday·February 16, 2026

11 papers—6 primary·5 cross-listed

01
[Submitted on 12 Feb 2026]
Low-energy $^{3}$ He( $α, γ$ ) $^{7}$ Be reaction within the Skyrme potential framework
Nguyen Le Anh · Nguyen Gia Huy · Dao Nhut Anh · Do Huy Tho · Hoang Thai An
\textbf{Background:} The $^{3}$ He( $α, γ$ ) $^{7}$ Be reaction plays a crucial role in the proton-proton chain and Big Bang nucleosynthesis, affecting solar neutrino fluxes and primordial element abundances. Experimental data at astrophysical energies remain uncertain due to the extremely low cross sections. \\ \textbf{Purpose:} This work uses a microscopic potential-model approach to construct the $^{3}$ He+ $α$ potential from the nucleon+ $α$ interaction, aiming to describe low-energy elastic scattering and to calculate the astrophysical $S$ factor of the $^{3}$ He( $α, γ$ ) $^{7}$ Be reaction. \\ \textbf{Method:} The nucleon-nucleus potential is derived from self-consistent Skyrme Hartree-Fock (HF) calculations extended to the continuum. The $^{3}$ He+ $α$ potential is then obtained by folding the HF potential with the $^{3}$ He density. A small number of scaling parameters is constrained by elastic-scattering data.\\ \textbf{Result:} The scaled Skyrme HF potential and folded potential simultaneously reproduce the low-energy $p$ + $α$ and $^{3}$ He+ $α$ $s$ -wave phase shifts, respectively. The calculated astrophysical $S$ factor of $^{3}$ He( $α, γ$ ) $^{7}$ Be shows good agreement with experimental data, yielding the recommended value $S_{34} (0) = 0.610 \pm 0.024$ ~keV~b. A moderate sensitivity of $S_{34} (0)$ to the choice of projectile density is also observed in the folding procedure. \\ \textbf{Conclusion:} The Skyrme HF-based potential provides a unified and predictive microscopic framework for describing both elastic scattering and radiative capture in light nuclei.
Comments:
8 pages, 5 figures, 3 tables. Accepted for publication in Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2602.12423 [pdf]
PRC(2026)·0 citations
02
[Submitted on 13 Feb 2026]
Dark matter effects on the properties of hybrid neutron stars
Jin-Biao Wei🇨🇳 · G. Wu🇨🇳 · H. Chen🇨🇳 · G. F. Burgio🇮🇹 · H.-J. Schulze🇮🇹
We study the effects of dark matter on the properties of hybrid neutron stars, in particular the influence on the mass-radius relation, the value of the maximum mass, and the hadron-quark phase transition. To single out the equilibrium configurations of dark-matter-admixed hybrid neutron stars (DHSs), we also study their radial oscillations. Both the stellar structure equations and the radial oscillation equations are solved for the two-fluid system, where the ordinary matter component and dark matter component couple only through gravity. For the ordinary matter components, we adopt the Brueckner-Hartree-Fock method for nuclear matter, and the Dyson-Schwinger or the field-correlator model for quark matter. For the dark matter component, we use a non-self-annihilating self-interacting fermionic model. We find that the presence of dark matter in DHSs leads to a decrease of the critical mass of the hadron-quark phase transition, a related possible onset of quark matter in dark-matter accreting stars, and a significant reduction of radial oscillation frequencies.
Comments:
11 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2602.12495 [pdf]
PRD(2026)·2 citations
03
[Submitted on 13 Feb 2026]
Chiral symmetry restoration and hyperon suppression in neutron stars
Bikai Gao🇯🇵
The ``hyperon puzzle'' remains a fundamental challenge in nuclear astrophysics. We investigate hyperon emergence in neutron star matter using the $S U (3)$ parity doublet model with chiral representation $(3, 3 ˉ) + (3 ˉ, 3)$ . This framework naturally incorporates chiral symmetry restoration and provides a systematic description of baryon masses in dense matter through the interplay between the chiral condensate and the chiral invariant mass $m_{0}$ . We find that the hyperon onset density exhibits strong sensitivity to $m_{0}$ : for $m_{0} = 500$ MeV, hyperons first appear at $1.9 n_{0}$ while for $m_{0} ≳ 750$ MeV, hyperons emerge only above $5 n_{0}$ . This delayed onset arises from the weakened density dependence of baryon masses at larger $m_{0}$ values. When the hyperon onset density exceeds the expected quark-hadron transition range ( $2$ -- $5 n_{0}$ ), matter undergoes deconfinement before hyperons populate, avoiding the EoS softening while maintaining consistency with massive neutron star observations. Our results demonstrate that chiral dynamics provides a natural resolution to the hyperon puzzle without requiring ad hoc repulsive hyperon interactions.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2602.12503 [pdf]
PRD(2026)·7 citations
04
[Submitted on 13 Feb 2026]
Dynamical Origin of Spectroscopic Quenching in Knockout Reactions
Jin Lei
Nucleon-removal reactions are a primary tool for extracting single-particle structure of rare isotopes, yet the ratio $R_{s} = σ_{e x p} / σ_{th}$ of measured to theoretical cross sections drops systematically below unity for deeply bound nucleons. I derive the exact effective three-body Hamiltonian for composite-projectile reactions using a sequential double Feshbach projection and show that the standard additive model misses two induced interactions: a non-additive term from virtual target excitations and a polarization potential from excluded projectile configurations. Their omission overestimates the stripping cross section, producing apparent quenching distinct from genuine nuclear-structure correlations. This mechanism offers a dynamical origin for the strong separation-energy dependence of the quenching ratio, a feature unique to knockout analyses. Existing four-body CDCC calculations for $^{6}$ Li validate the framework: the proper Feshbach reference reproduces elastic scattering data, while a phenomenological optical potential double counts the breakup absorption and fails.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2602.12690 [pdf]
2 citations
05
[Submitted on 13 Feb 2026]
Phase diagrams of BCS-BEC crossover in asymmetric nuclear matter
K. D. Duan · X. L. Shang
The phase structure of the BCS-BEC crossover for neutron-proton superfluid in asymmetric nuclear matter is systematically investigated, with particular focus on the roles of the angle-dependent gap (ADG) and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states. Phase diagrams in the T-alpha, alpha-rho, and T-rho planes are constructed using both angle-averaged and angle-dependent gap treatments, enabling a unified analysis of the interplay between the FFLO pairing, ADG, and normal-superfluid phase separation (PS). The results confirm that the crossover is primarily density-driven. In the weak-coupling BCS regime, isospin asymmetry suppresses the stability of the homogeneous superfluid phase and drives the system toward PS, while the FFLO and ADG mechanisms partially alleviate this suppression. Although the ADG itself does not extend the asymmetry window for superfluidity, in combination with the FFLO state it enlarges the asymmetry range over which superfluidity survives and significantly reduces PS. At high density, these combined effects can nearly eliminate PS. However, as density decreases, ADG-induced suppression of PS is progressively weakened, due to both the reduced destructive effect of isospin asymmetry and the decreasing D-wave fraction in the 3SD1 channel. In general, the system evolves smoothly from a D-wave-dominated superfluid at high density to an S-wave superfluid at low density, with a corresponding weakening of ADG effects. Furthermore, the ADG lifts the orientational degeneracy of the FFLO state, resulting in two distinct FFLO-ADG phases separated by a first-order transition. In contrast, in the BEC regime, the FFLO and ADG states vanish, while the PS persists, leading to an inhomogeneous mixed phase at low temperatures and large asymmetries, where the superfluid component forms a BEC of deuterons.
Comments:
10 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2602.12726 [pdf]
0 citations
06
[Submitted on 13 Feb 2026]
Subleading D-like Three-Nucleon Interactions
Henri Paul Huesmann🇩🇪 · Hermann Krebs🇩🇪 · Evgeny Epelbaum🇩🇪
We consider subleading contributions to the three-nucleon force from tree-level diagrams involving a single-pion exchange and a contact interaction between two nucleons, which appear at fifth order in the chiral expansion. We show that the corresponding D-like three-nucleon potential depends on 16 low-energy constants, which need to be determined from few-body data. Assuming that their numerical values are governed by the intermediate {\Delta}(1232) excitation mechanism, the considered three-nucleon force can be approximated using 4 low-energy constants that parametrize the short-range nucleon-nucleon to nucleon-{\Delta} transition amplitude.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2602.12879 [pdf]
NPA(2026)·4 citations
07
[Submitted on 12 Feb 2026] (cross-list from astro-ph.HE)
First-Principles Polar-Cap Currents in Multipolar Pulsar Magnetospheres
Chun Huang
X-ray pulse-profile modeling of millisecond pulsars offers a direct route to measuring neutron star masses and radii, thereby constraining the dense-matter equation of state. However, standard analyses typically rely on \emph{ad hoc} hotspot parameterizations rather than self-consistent physical models. While connecting surface heating directly to the magnetospheric geometry provides a more natural physical pathway, computing global magnetospheric solutions is too computationally expensive to perform on-the-fly during parameter inference. In this work, we bridge this gap by deriving fully analytic, first-principles expressions for surface return currents in mixed dipole--quadrupole magnetospheres. Working within force-free electrodynamics, we generalize the field-aligned current invariant $Λ$ , the crucial scalar that maps the far-zone magnetic structure to the near-zone heating rate, from the standard dipole approximation to arbitrary quadrupolar configurations. We demonstrate that even when the quadrupole component is sub-dominant in the far zone (the mixing regime), using a dipole-based heating prescription fails to capture the significant enhancement or suppression of the return-current density on the polar cap. Our consistent quadrupole-aware framework reveals that these multipolar currents redistribute the surface heating, leading to systematic discrepancies in predicted pulse profiles that are amplified by atmosphere beaming and can reach $\sim 30%$ near pulse peaks. These results provide a rigorous analytic foundation for mapping global magnetic geometry to surface heating in multipolar magnetospheres, enabling physically consistent inference beyond the idealized dipole approximation.
Comments:
23 pages, 6 figures, Accepted publication in ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2602.12376 [pdf]
ApJ(2026)·1 citation
08
[Submitted on 12 Feb 2026] (cross-list from astro-ph.HE)
Correlated and uncorrelated Monte Carlo neutron capture rate variations in weak $r$ -process simulations
Atul Kedia · Jeffrey M. Berryman · Jonathan Cabrera Garcia · Jutta E. Escher · Oliver C. Gorton · Erika M. Holmbeck · Gail C. McLaughlin · Cole D. Pruitt · Andre Sieverding · Rebecca Surman
Reliable predictions of weak rapid neutron capture ( $r$ -process) abundances require a systematic treatment of nuclear physics uncertainties, especially neutron capture rates far from stability. We employ new neutron capture rates from cross sections calculated with Yet Another Hauser-Feshbach Code ( $YAHFC$ ) using an uncertainty-quantified Koning-Delaroche potential modified for use on neutron-rich systems. Using these rates as a baseline, we perform Monte-Carlo studies with independent rate variations (uncorrelated Monte Carlo) and find correlations between specific neutron capture rates and the resulting elemental abundances for the three weak r-process scenarios: two separate simulations of neutron star merger remnant accretion disks and a simulation of a magnetorotational supernova. We discuss the underlying nuclear dynamics that give rise to these correlations and the role of astrophysical conditions in them. We demonstrate how reducing the uncertainty in these rates would improve the prospects for conducting precision $r$ -process studies in the future. We additionally present a correlated Monte Carlo study, which incorporates the full covariance matrix that describes the relationships between individual neutron capture rates that arise from an uncertainty-quantified optical potential. We find that the magnitude of the uncertainty in the abundance pattern is similar to that produced by an uncorrelated Monte Carlo that employs only the on-diagonal components of the covariance matrix. We show how correlations restructure how the abundances co-vary, but do not necessarily decrease the overall uncertainty envelope.
Comments:
21 pages, 13 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2602.12428 [pdf]
2 citations
09
[Submitted on 13 Feb 2026] (cross-list from hep-ph)
NNLL $^{'}$ resummation of azimuthal decorrelation for boosted top quark pair production at the LHC
Qian-Shun Dai🇨🇳 · Ming-Jun Liu🇨🇳 · Ding Yu Shao🇨🇳
The precision program of the Large Hadron Collider (LHC) increasingly relies on the boosted regime, where top quark properties are probed at the TeV scale. However, the simultaneous presence of heavy quark mass effects and large logarithmic corrections from soft radiation poses a significant challenge for theoretical predictions. In this work, we develop a transverse momentum dependent (TMD) factorization and resummation framework for boosted top quark pair production in the back-to-back limit at the LHC. By employing a two step matching procedure, matching QCD through $SCET + HQET$ onto $SCET + bHQET$ , we systematically resum large logarithms associated with both the top quark mass and the azimuthal decorrelation. A key component of our formalism is the first extraction of the two-loop ultra-collinear function, obtained via the refactorization of the fully differential massive soft function. This result completes the set of perturbative ingredients required to achieve $NNLL^{'}$ accuracy for the azimuthal decorrelation distribution. Our framework establishes a new benchmark for heavy-quark TMD resummation in the boosted limit at hadron colliders.
Comments:
29 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2602.12572 [pdf]
JHEP(2026)·1 citation
10
[Submitted on 13 Feb 2026] (cross-list from hep-ph)
Meson Form Factors
Johan Bijnens (Lund)🇸🇪
We give an introduction to and a short overview of light meson form factors. We first discuss the classical picture and how it then fits in with amplitudes in quantum field theory. We give a short overview of the main theoretical methods and then discuss pion, kaon, eta and eta' form factors.
Comments:
8 pages, article for the Encyclopedia of Particle Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2602.12715 [pdf]
0 citations
11
[Submitted on 13 Feb 2026] (cross-list from hep-ph)
Rotating synchrotron radiation: Photon emission from magnetized and rotating quark-gluon plasma
Matteo Buzzegoli🇷🇴 · Sergiu Busuioc🇷🇴 · Jonathan D. Kroth🇺🇸 · Nandagopal Vijayakumar🇺🇸 · Kirill Tuchin🇺🇸
This paper investigates the production of non-prompt photons originating from rotating synchrotron radiation (RoSyRa), specifically the emission of photons by a rigidly rotating quark-gluon plasma in thermal equilibrium, in the presence of an external magnetic field. We compute the non-prompt photon spectrum and its elliptic flow ( $v_{2}$ ) at mid-rapidity. In particular, we investigate the finite volume effects. We find that at low transverse momentum, the magnetic field induces a significant $v_{2}$ , while the plasma rotation boosts the synchrotron radiation of negatively charged quarks. These findings make RoSyRa a viable candidate mechanism to resolve the "direct photon puzzle."
Comments:
25 pages, 17 figures. v2: published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2602.13044 [pdf]
PRD(2026)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE