Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2607.01599

Dispersive-optical-model analysis of the asymmetry dependence of neutron skins

R. A. Ramon·M. C. Atkinson·W. H. Dickhoff
View original source ↗Read source document ↗Export metadata ↓

Abstract

New dispersive optical model analyses of ${}^{54}$Fe and ${}^{90}$Zr together with updated results for ${}^{40}$Ca, ${}^{48}$Ca, and the earlier result for ${}^{208}$Pb shed light on the behavior of neutron skins in nuclei. Starting with a negative skin for ${}^{40}$Ca, a trend increasing somewhat stronger than linear emerges when the neutron skin of these nuclei is considered as a function of asymmetry, $(N-Z)/A$, and linked to the Green's function Monte Carlo results for asymmetric He nuclei. This general trend is consistent with the expectation that nuclei near the neutron drip line are expected to have very large neutron skins. The present analysis therefore motivates the question of which nuclei provide the most relevant link to neutron star physics.

Explore related subjects

nucl-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R. A. Ramon, M. C. Atkinson, W. H. Dickhoff. 2026-07-02. Dispersive-optical-model analysis of the asymmetry dependence of neutron skins. https://arxiv.org/abs/2607.01599

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Dimer Effective Field Theory

While chiral perturbation theory for mesons is characterized by a momentum expansion in $Q/Λ_χ$ with $Λ_χ\sim 1$ GeV, existing formulations of effective theory for nucleon-nucleon scattering deviate from data at $Q\sim 300$ MeV or lower. We offer heuristic evidence that unsuspected nonanalytic structure exists in the complex momentum plane obstructing the effective field theory expansion in the spin-triplet channels, associated with the peak of the angular momentum barrier whose energy in low partial waves satisfies $k=\sqrt{ME} \sim 300$ MeV. With this motivation, we construct a meromorphic function of $k^2$ we call the $C$-matrix, for which the radius of convergence of its Taylor expansion in $k^2$ is equivalent to that of the momentum expansion of the effective field theory. Thus the range of validity of the effective theory is directly related to the pole structure of the $C$-matrix. We uncover that pole structure and confirm that it is the source of the obstruction. The systematic inclusion of dimer fields as propagating degrees of freedom in the effective theory to account for those poles results in cut-off insensitive fits at order $Q^0$ to most of the lower partial wave phase shifts up to the pion production threshold, using only the one pion exchange part of the long-range nucleon-nucleon interaction. Our theory should be applicable to the singular potentials regularly found in atomic physics as well.

nucl-th↗
arXiv2026

Three-dimensional orbital-free density functional theory description of nuclear pasta in the inner crust of neutron stars

Background: In the bottom layer of the inner crust of neutron stars, various crystalline structures are expected to emerge that are collectively called ``nuclear pasta.'' It is desirable to know properties of nuclear pasta in a wide variety of conditions for astrophysical applications. However, three-dimensional fully-microscopic calculations require huge computational effort that makes it still challenging to carry out systematic calculations. Purpose: In this paper, we propose an efficient method to calculate various nuclear pasta configurations in a non-empirical manner, based on three-dimensional orbital-free density functional theory (OF-DFT). We demonstrate the feasibility of the proposed approach by applying it to densities across the inner crust of neutron stars. Methods: As a first application of OF-DFT for nuclear pasta, we employ the second-order extended Thomas-Fermi (ETF) expansion of Skyrme energy density functional (EDF) to construct an EDF that depends only on neutron and proton number densities. Based on the variational principle, we derive Euler-Lagrange equations to determine optimal neutron and proton density distributions and solve them self-consistently. In this work, we call this approach the self-consistent ETF (SC-ETF) method. Results: We perform three-dimensional SC-ETF calculations with various box sizes. We successfully obtain various pasta structures, depending on given average nucleon number densities, consistent with earlier studies. Moreover, we find other exotic structures, such as bending and/or connected rods, slabs with a hole, etc., underlining the advantage of the self-consistent formalism. Conclusions: We demonstrate that the SC-ETF method proposed in this study, which can be regarded as a realization of OF-DFT, is a promising tool that can efficiently describe complex pasta structures without empirical assumptions on geometric shapes.

nucl-th↗
arXiv2026

Microscopic analysis of M1 scissors mode in $^{254}$No

The low-energy $M1$ orbital scissors mode (SM) was recently observed by Oslo group in deformed nucleus $^{254}$No. This is the heaviest nucleus where SM was ever experimentally found. We propose the analysis of SM, together with the spin-flip $M1$ resonance, within fully self-consistent Quasiparticle Random-Phase Approximation (QRPA) with Skyrme forces SG2, SLy4 and SLy5. The impact of "tensor" $J^2$-term, introduced by perturbative (on the base of SG2) and consistent (SLy5) ways, is analyzed and shown to be noticeable but not decisive. The deformation-induced coupling of $M1$ and $E2$ states is inspected. The calculations reasonably describe Oslo's experimental data. The best agreement is obtained for SLy5. A fine structure of SM in $^{254}$No is predicted. A significant constructive interference of the dominant orbital and minor spin-flip contributions to $M1$ strength at SM energy region is found. What is remarkable, our analysis of distributions of the convective nuclear currents challenges the scissors-like flow usually assumed for SM.

nucl-th↗