Nuclear Theory·nucl-th

Wednesday·April 23, 2025

10 papers—6 primary·4 cross-listed

01
Angular structure of many-body correlations in atomic nuclei: From nuclear deformations to diffractive vector meson production in $γ A$ collisions
Jean-Paul Blaizot🇫🇷 · Giuliano Giacalone🇫🇷
There is growing evidence that high-energy scattering processes involving nuclei can offer unique insights into the many-body correlations present in nuclear ground states, in particular those of deformed nuclei. These processes involve, for instance, the collective anisotropic flows in heavy-ion collisions, or the diffractive production of vector mesons in photo-nuclear ( $γ A$ ) interactions. In this paper, we use a classical approximation and simple analytical models in order to exhibit characteristic and universal features of ground-state correlation functions that result from the presence of a deformed intrinsic state. In the case of a small axial quadrupole deformation, we show that the random rotation of the intrinsic density of the nucleus leads to a specific quadrupole modulation of the lab-frame two-body density as a function of the relative azimuthal angle. As a phenomenological, albeit academic application, we analyze the diffractive production of vector mesons in high-energy $γ +^{8}$ Be collisions. This demonstrates with the simplest deformed nucleus how the two-body correlations impact the $∣ t ∣$ dependence of the incoherent cross sections.
nucl-thhep-exhep-phnucl-exEPJA(2025)·14 citations
02
Study of neutron-deficient nucleus 224Np and its {\alpha} decay by particle-number-conserving method in the framework of deformed shell model
Xiao-Tao He · Kun Huang · T. M. Shneidman · N. V. Antonenko · Jun Zhang · Hong-qiang You
The particle-number-conserving (PNC) method in the framework of the deformed shell model (DSM) is employed to study the properties of the newly discovered short-lived neutron-deficient nucleus 224Np and its {\alpha}-decay. The calculated energy of {\alpha}-particle lies within 300 keV of the experimental data. This is the first application of the PNC method to the region of neutron-deficient nuclei. This work provides the first attempt to combine the microscopic PNC theory with empirical formulas to study the nuclear {\alpha} decay. The configurations of ground states are assigned as {\pi}5/2-[523]{\otimes}{\nu}5/2+[633] for 224Np, {\pi}1/2-[530]{\otimes}{\nu}3/2+[642] for 220Pa, {\pi}3/2+[651]{\otimes}{\nu}1/2-[501] for 216Ac, and {\pi}7/2-[514]{\otimes}{\nu}3/2-[501] for 212Fr. The absence of the Z = 92 subshell closure in 224Np is explained by analyzing the proton single-particle levels. Low-lying excited statesare predicted for nuclei along the {\alpha}-decay chain by the PNC method. Based on the PNC predicted {\alpha}-decay energy and the assigned configurations, the {\alpha}-decay half-lives are calculated by the empirical formulas, in which the angular momentum taken away by the {\alpha} particle is taken into account. The angular momentum have an important effect on the {\alpha}-decay half-life. The errors of the empirical formulas calculation are in two orders of magnitude with the experimental data.
nucl-thPRC(2025)·2 citations
03
Charge dependent nucleon-nucleon potentials in covariant chiral effective field theory
Yang Xiao🇨🇳 · Jun-Xu Lu🇨🇳 · Chun-Yan Song🇨🇳 · Li-Sheng Geng🇨🇳
The charge-dependent nucleon-nucleon ( $N N$ ) interaction plays a crucial role in understanding the nuclear structure and reaction problems. In this work, we explore the charge-dependent $N N$ interaction in covariant chiral effective field theory. By incorporating the isospin-breaking contributions, we derive the charge-dependent covariant chiral $N N$ potential up to next-to-next-to leading order (NNLO). The calculated $n p$ and $pp$ phase shifts are in satisfactory agreement with the PWA93 partial wave analysis. Our results contribute to a deeper understanding of isospin-breaking effects in nuclear forces and provide a solid foundation for future studies of nuclear structure and reactions within the covariant framework.
nucl-thPRC(2026)·3 citations
04
Electroweak form factors of baryons in dense nuclear matter
G. Ramalho🇰🇷 · K. Tsushima🇧🇷 · Myung-Ki Cheoun🇰🇷
There is evidence that the properties of hadrons are modified in a nuclear medium. Information about the medium modifications of the internal structure of hadrons is fundamental for the study of dense nuclear matter and high-energy processes, including heavy-ion and nucleus--nucleus collisions. At the moment, however, empirical information about medium modifications of hadrons is limited; therefore, theoretical studies are essential for progress in the field. In the present work, we review theoretical studies of the electromagnetic and axial form factors of octet baryons in symmetric nuclear matter. The calculations are based on a model that takes into account the degrees of freedom revealed in experimental studies of low and intermediate square transfer momentum $q^{2} = - Q^{2}$ : valence quarks and meson cloud excitations of baryon cores. The formalism combines a covariant constituent quark model, developed for a free space (vacuum) with the quark--meson coupling model for extension to the nuclear medium. We conclude that the nuclear medium modifies the baryon properties differently according to the flavor content of the baryons and the medium density. The effects of the medium increase with density and are stronger (quenched or enhanced) for light baryons than for heavy baryons. In particular, the in-medium neutrino--nucleon and antineutrino--nucleon cross-sections are reduced compared to the values in free space. The proposed formalism can be extended to densities above the normal nuclear density and applied to neutrino--hyperon and antineutrino--hyperon scattering in dense nuclear matter.
nucl-thhep-exhep-lathep-ph+1Symmetry(2025)·8 citations
05
Compatibility of recent $Ξ$ -nuclear bound state signals
E. Friedman🇮🇱 · A. Gal🇮🇱
J-PARC E05 reported recently a hint of a $Ξ^{-} -^{11} B$ nuclear state in the $^{12} C (K^{-}, K^{+})_{Ξ}^{12} Be$ spectrum, bound by $B_{Ξ^{-}} = 8.9 \pm 1.4_{- 3.1}^{+ 3.8}$ MeV. Using a density-dependent $Ξ$ -nuclear optical potential $V_{opt}^{Ξ} (ρ)$ we explore to what extent a $Ξ_{1 s}^{-}$ assignment of this nuclear state is compatible with $Ξ_{1 s}^{-}$ and $Ξ_{1 p}^{-}$ nuclear-state interpretations of $Ξ^{-}$ capture events in light emulsion-nuclei experiments. We find that the only acceptable $Ξ_{1 s}^{-}$ assignment at present, barring an abnormally strong repulsive $ρ^{2}$ component of $V_{opt}^{Ξ} (ρ)$ , is that for the $Ξ^{-} -^{11} B$ signal. This finding supports reassigning $Ξ^{-}$ capture events in $^{14}$ N, originally assigned as $Ξ_{1 s}^{-} -^{14} N$ nuclear states, to $Ξ_{1 p}^{0} -^{14} C$ nuclear states. The depth of $V_{opt}^{Ξ} (ρ)$ at nuclear-matter density $ρ_{0} = 0.17$ fm $^{- 3}$ is then $- V_{opt}^{Ξ} (ρ_{0}) \sim 21$ MeV.
nucl-thhep-phnucl-exPLB(2025)·7 citations
06
Shear Viscosity and Electrical Conductivity of Rotating Nuclear Medium in Hadron Resonance Gas and Nambu-Jona Lasinio Models
Ashutosh Dwibedi · Dani Rose J Marattukalam · Nandita Padhan · Dushmanta Sahu · Jayanta Dey · Kangkan Goswami · Arghya Chatterjee · Sabyasachi Ghosh · Raghunath Sahoo
Motivated by recent observations of spin polarization and alignment in heavy-ion collisions, we study the impact of rotation on the transport properties of strongly interacting matter within kinetic theory in the relaxation time approximation. Our analysis focuses on the anisotropic shear viscosity--parallel ( $η_{∥}$ ), perpendicular ( $η_{⊥}$ ), and Hall ( $η_{\times}$ )--and electrical conductivity-- $σ_{∥}$ , $σ_{⊥}$ , and $σ_{\times}$ --induced by the Coriolis force in a rotating medium. We employ two approaches: a combined quark-gluon plasma--hadron resonance gas (QGP--HRG) framework and a two-flavor Nambu--Jona-Lasinio (NJL) model. In the QGP--HRG description, noninteracting HRG (massless partonic) degrees of freedom are used below (above) the transition temperature. In the NJL model, rotation enters through spinorial connections in the Lagrangian, and the constituent quark masses are obtained over the full temperature range. Rotation suppresses the chiral condensate and slightly enhances the transport coefficients for phenomenologically relevant angular velocities. Assuming a temperature-dependent angular velocity consistent with standard cooling, we find that $η_{∣∣, ⊥, \times} / s$ and $σ_{⊥, \times} / T$ exhibit a valley-like temperature dependence, with reduced magnitudes compared to the isotropic $η / s$ and $σ / T$ obtained without rotation. At zero net baryon density, rotation generates a sizable nondissipative Hall-like conductivity, unlike the case with magnetic fields where baryon and antibaryon contributions cancel.
nucl-thhep-thPhys. Rev. C 113, 044903 (2026)
07
Compton Form Factor Extraction using Quantum Deep Neural Networks
Brandon B. Le🇺🇸 · Dustin Keller🇺🇸
We extract Compton form factors (CFFs) from deeply virtual Compton scattering measurements at the Thomas Jefferson National Accelerator Facility (JLab) using quantum-inspired deep neural networks (QDNNs). The analysis implements the twist-2 Belitsky-Kirchner-Müller formalism and employs a fitting strategy that emulates standard local fits. Using pseudodata, we benchmark QDNNs against classical deep neural networks (CDNNs) and find that QDNNs often deliver higher predictive accuracy and tighter uncertainties at comparable model complexity. Guided by these results, we introduce a quantitative selection metric that indicates when QDNNs or CDNNs are optimal for a given experimental fit. After obtaining local extractions from the JLab data, we perform a standard neural-network global CFF fit and compare with previous global analyses. The results support QDNNs as an efficient and complementary tool to CDNNs for CFF determination and for future multidimensional studies of parton distributions and hadronic structure.
↳ cs.LGhep-phnucl-thquant-phPRC(2026)·6 citations
08
Coupled Instantons In A Four-Well Potential With Application To The Tunneling Of A Composite Particle
Pervez Hoodbhoy · M. Haashir Ismail · M. Mufassir
Coupled instantons are introduced by generalizing the double well potential to multiple mutually coupled wells. Physically this corresponds to the simultaneous tunneling of multiple degrees of freedom. A system with four equal minima is examined in detail. It has three instanton types or flavors with distinct actions. For weak coupling and subject to there being a single large (or small) parameter, the interactive system can be handled perturbatively. The zero mode problem arising from time translation symmetry is handled via the Fadeev-Popov procedure. A diagrammatic procedure allows corrections to the fluctuation determinant to be calculated systematically. Independent instanton contributions are summed over by extending the dilute gas approximation to three flavors and energy splittings of the lowest four states is calculated. All tunneling amplitudes are concisely expressed in terms of elementary functions. While the model is possibly useful for a variety of physical systems, an application is made here to the tunneling of a composite particle in one dimension.
↳ quant-phcond-mat.othermath-phmath.MP+10 citations
09
On the Klein-Gordon bosonic fields in the Bonnor-Melvin spacetime with a cosmological constant in rainbow gravity: Bonnor-Melvin Domain Walls
Omar Mustafa🇹🇷 · Abdullah Guvendi🇹🇷
We investigate the effect of rainbow gravity on Klein-Gordon (KG) bosons in the background of the magnetized Bonnor-Melvin (BM) spacetime with a cosmological constant. We first show that the very existence of the sinusoidal term $\sin^2(\sqrt{2\Lambda}r)$, in the BM space-time metric, suggests that $\sin^2(\sqrt{2\Lambda}r) \in [0,1],$ which consequently restricts the range of the radial coordinate $r$ to $r \in [0,\pi/\sqrt{2\Lambda}]$. Moreover, we show that at $r = 0$ and $r = \pi/\sqrt{2\Lambda}$, the magnetized BM-spacetime introduces domain walls (infinitely impenetrable hard walls) within which the KG bosonic fields are allowed to move. Interestingly, the magnetized BM-spacetime introduces not only two domain walls but a series of domain walls. However, we focus on the range $r \in [0,\pi/\sqrt{2\Lambda}]$. A quantum particle remains indefinitely confined within this range and cannot be found elsewhere. Based on these findings, we report the effects of rainbow gravity on KG bosonic fields in BM-spacetime. We use three pairs of rainbow functions: $ f(\chi) = \frac{1}{1 - \tilde{\beta} |E|}, \, h(\chi) = 1 $; $ f(\chi) = (1 - \tilde{\beta} |E|)^{-1}, \, h(\chi) = 1 $; and $ f(\chi) = 1, \, h(\chi) = \sqrt{1 - \tilde{\beta} |E|^\upsilon} $, with $\upsilon = 1,2$. Here, $\chi = |E| / E_p$, $\tilde{\beta} = \beta / E_p$, and $\beta$ is the rainbow parameter. We found that while the pairs $(f,h)$ in the first and third cases fully comply with the theory of rainbow gravity and ensure that $E_p$ is the maximum possible energy for particles and antiparticles, the second pair does not show any response to the effects of rainbow gravity. We show that the corresponding bosonic states can form magnetized, spinning vortices in monolayer materials, and these vortices can be driven by adjusting an out-of-plane aligned magnetic field.
↳ gr-qcnucl-thEPJC(2025)·6 citations
10
Spin structure of spin-1 charmonium states near $T_{c}$
HyungJoo Kim🇯🇵
We investigate the spin structure of the $1^{--}$ and $1^{++}$ charmonium states near the critical temperature using QCD sum rules. To this end, we compute the contribution of the dimension-4 twist-2 gluon operator to the two-point function of heavy vector and axial vector currents in a rotating frame. As temperature increases, the quark spin contribution slightly increases, while the quark orbital angular momentum decreases by a comparable amount. The gluon contribution remains nearly unchanged. These thermal changes cancel each other, ensuring that the total spin is preserved even at finite temperature.
↳ hep-phnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE