Nuclear Theory·nucl-th

Tuesday·May 26, 2026

13 papers—5 primary·8 cross-listed

01
[Submitted on 23 May 2026]
Intrinsic generation of angular momenta and entanglement in fission
B. Li · D. D. Zhang · D. Vretenar · T. Nikšić · P. W. Zhao · J. Meng
Nuclear time-dependent density functional theory is used to investigate spin generation and entanglement of fission fragments in spontaneous fission of $^{252}$ Cf, incorporating both axial and non-axial deformations. Axially symmetric fission trajectories enforce strict constraints: counter rotation (twisting mode) along the fission axis and equiprobable bending/wriggling modes perpendicular to it. Non-axial modes broaden the distributions of fission fragment spin projection on the fission axis, and allow for axial (tilting) collective rotations, which are forbidden on axially symmetric trajectories. Mutual information analysis reveals that axial-symmetry breaking reduces spin-spin correlations along the fission axis of symmetric cases, while perpendicular correlations remain more resilient. The effect of triaxial degrees of freedom on the opening angle distribution between the spins of the fission fragments is analyzed.
Comments:
28 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.24466 [pdf]
PRL(2026)·1 citation
02
[Submitted on 23 May 2026]
A unified classification-quantification framework for bubble-like nuclei within the extended quantum molecular dynamics model
Ge Ren · Chun-Wang Ma · Xi-Guang Cao · Kai-Xuan Cheng · Jie Pu
A systematic study of relaxed low-energy cluster configurations for all nuclides listed in the AME2020 database is performed within the extended quantum molecular dynamics (EQMD) framework, with frictional cooling enabling stable relaxation. A unified classification-quantification framework based on the dimensionless parameters $B H T U$ is established to characterize bubble-like nuclear morphologies. The factor $B$ , determined from the number of inflection points in the radial density profile, categorizes nuclei into droplet ( $B = 0$ ), bubble ( $B = 1$ ), and toroidal bubble ( $B = 2$ ). The parameter $H$ defines the degree of central density depletion, while $T$ and $U$ characterize the relative surface thickness and the relative size of the internal low-density region, respectively. Light nuclei are predominantly droplet-like with $B = 0$ , $H = 0$ , $T = 1$ , $U = 0$ . Most medium-mass nuclei have $B = 1$ , consistent with previous studies, especially in the vicinity of $^{40}$ Ca and the neutron-rich region, where nuclei show a pronounced central hollowing with large $H$ and $U$ values, identifying them as prime candidates for experimental searches for bubble structures. Toroidal bubble nuclei ( $B = 2$ ), emerging for $Z \approx 25$ and prevalent in heavy systems, display a local density minimum at intermediate radius together with a shell-like low-density region. Furthermore, bubble structures are found to be widespread in the superheavy region, in agreement with earlier studies. This parameter scheme not only reveals the morphological richness of nuclei but also establishes a predictive framework for exploring exotic nuclear shapes, thereby opening new avenues for future theoretical and experimental investigations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2605.24676 [pdf]
0 citations
03
[Submitted on 24 May 2026]
Thermal Spin Polarization Driven by Nuclear Spin-Orbit Coupling in Neutron Star Pasta
Hiroyuki Tajima · Yuta Sekino · Hiroshi Funaki · Shota Kisaka · Nobutoshi Yasutake · Mamoru Matsuo
We discuss anomalous spin polarization on the surface of nuclear pasta in a neutron star, driven by a nuclear spin-orbit interaction. We present an effective two-band model of surface-localized neutrons near the nuclear pasta. The central point is the emergence of a Rashba-type spin-orbit hybridization generated by the neutron--nucleus spin-orbit force in the presence of the strong density gradient normal to the pasta surface. Starting from a single-particle Hamiltonian with a central potential and a standard nuclear spin-orbit interaction, we show that the surface spin polarization occurs due to the thermal inhomogeneity even in the absence of a magnetic field. Our study links neutron-star physics and solid-state spintronics and would contribute to understanding the interplay between spin dynamics and strong magnetic fields.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Quantum Gases (cond-mat.quant-gas); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
2605.25067 [pdf]
0 citations
04
[Submitted on 25 May 2026]
A higher-harmonic observable for the chiral magnetic effect in heavy-ion collisions
Han-Sheng Li🇺🇸 · Yu-Shan Chang🇺🇸 · Yi Yang🇹🇼 · Fuqiang Wang🇺🇸
The chiral magnetic effect (CME) is a phenomenon in which electric charge is separated by a strong magnetic field from local domains of chirality imbalance in quantum chromodynamics. The CME-sensitive azimuthal correlator difference $Δ γ$ between opposite- and same-sign charged hadron pairs is designed to detect charge separation along the magnetic field, on average perpendicular to the reaction plane. However, the search for the CME is hindered by large background contributions to $Δ γ$ from particle correlations coupled with elliptic flow. In this work, we explore higher-harmonic components in differential $Δ γ (ϕ_{pair})$ as a function of the pair azimuthal angle. Such components could arise from event-by-event fluctuations of the magnetic fields throughout the collision zone, in both direction and magnitude. We show by using heavy-ion physics models that the hexadecapole component of $Δ γ (ϕ_{pair})$ is sensitive to the CME and insensitive to physics backgrounds. This could offer a unique observable for the CME that is robust against background contributions.
Comments:
8 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2605.25487 [pdf]
0 citations
05
[Submitted on 25 May 2026]
Multipole tomography of atomic nuclei with symmetry-conserved theories
X. Sun · J. Dobaczewski · W. Nazarewicz · H. Wibowo
To define the intrinsic reference frame and multipole moments of angular-momentum- $J$ -conserving many-body wave functions, we introduce two-body conditional probabilities of finding two nucleons at different positions in space. In this way, quadrupole deformations of states with $J \leq 1/2$ , which are not accessible via spectroscopic one-body quadrupole moments, can be characterized. We illustrate the method with nuclear density functional theory calculations for $J = 0$ states of $^{16}$ O and $^{20}$ Ne, the latter obtained by restoring rotational symmetry of prolate or oblate intrinsic configurations. We show that the two-body quadrupole shape characterizations differ from one-body moments obtained from broken-symmetry states.
Comments:
9 pages, 3 figures, submitted version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2605.26088 [pdf]
1 citation
06
[Submitted on 22 May 2026] (cross-list from hep-ph)
Solar Axions from Nuclear Transitions
Tanmoy Kumar🇮🇳 · Newton Nath🇮🇳
We investigate the possibility of detecting 14.4 keV and 9.4 keV solar axions and axion-like particles that could be produced in the M1 nuclear transitions of $^{57}$ Fe and $^{83}$ Kr, respectively. To do so, we used data from soft X-ray observations of the quiet Sun collected by the Solar X-ray Monitor (XSM) on board India's Chandrayaan-2 lunar mission. We observe that although the effective axion-nucleon couplings for $^{83}$ Kr and $^{57}$ Fe differ only slightly, their fluxes differ by nearly three orders of magnitude. Consequently, the limit on $∣ g_{a N}^{eff} \times g_{aγ γ} ∣$ and only $g_{aγ γ}$ vs. $m_{a}$ provide more than an order-of-magnitude stronger constraint for Fe than for Kr.
Comments:
20 pages, 5 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2605.24121 [pdf]
0 citations
07
[Submitted on 23 May 2026] (cross-list from hep-ph)
Low-lying $Λ$ and $Σ$ resonances studied with the forward $K^{*}$ productions off the proton induced by a high-momentum $π$ beam
H. Kamano🇯🇵 · T.-S. H. Lee🇺🇸
We develop a novel model utilizing the forward $K^{*}$ production reaction off the nucleon, $π N \to K^{*} M B$ , induced by a high-momentum $π$ beam, as a tool to study low-lying $Y^{*}$ resonances below and just above the $K ˉ N$ threshold. Because conventional $K^{-} p$ scattering experiments face difficulties in directly accessing this kinematic region, the proposed reaction offers a valuable complementary approach for $Y^{*}$ spectroscopy. The constructed model is based on the one-meson exchange mechanism, which is known to dominate forward-angle production at high energies, and the half-off-shell scattering amplitudes from the ANL-Osaka dynamical coupled-channels models (Model A and Model B). We predict various observables, including differential cross sections and angular distributions. Our results demonstrate significant enhancements in the subthreshold region of the invariant mass spectra. Notably, we show that overlapping resonances, such as a potential new $3/ 2^{+}$ $Σ$ state and the well-established $Σ (1385) 3/ 2^{+}$ , can constitute a single peak in the $π Λ$ mass spectrum, indicating that the existence of previously unconfirmed subthreshold states cannot be ruled out by analyzing only the existing mass spectrum data. Furthermore, we find that angular distributions provide strong discriminatory power to disentangle such overlapping states through partial-wave interference effects, while the $t^{'}$ and $ϕ_{M}^{*}$ dependencies provide crucial constraints on the high-energy production mechanisms. Our predictions for these highly sensitive observables can facilitate high-statistics measurements, which are accessible at modern hadron facilities such as J-PARC, to unravel the $S = - 1$ $Y^{*}$ mass spectrum.
Comments:
22 pages, 20 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2605.24412 [pdf]
PRC(2026)·0 citations
08
[Submitted on 25 May 2026] (cross-list from physics.atom-ph)
The Pseudospectral Method for the Dirac Equation with Confining Potential
Dengshan Liu · Huihui Xie · Pengxiang Du · Jian Li · Tomoya Naito
We observe that solving the Dirac equation for confined potentials using the generalized pseudospectral (GPS) method leads to deteriorating convergence of energy eigenvalues and highly oscillatory in wave functions as the confinement radius decreases. It is found that this issue stems from the first-order differentiation formulation employed in GPS method. Motivated by this insight, we adopt the kinetically balanced generalized pseudospectral method, which incorporates the kinetically-balanced condition into the GPS method. Numerical results demonstrate that the mono-kinetically-balanced generalized pseu dospectral (MKB-GPS) method yields converged energy eigenvalues and generates smooth, continuous wave functions. This is the first application of the MKB-GPS method to confined potentials, and its effectiveness is validated for small confinement radii.
Comments:
14 pages, 10 figures
Subjects:
Atomic Physics (physics.atom-ph); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:
2605.25390 [pdf]
0 citations
09
[Submitted on 25 May 2026] (cross-list from astro-ph.HE)
Superfluid fraction and effective ion mass in the crystalline crust of a neutron star: role of interband response
Nicolas Chamel
Neutron superfluidity in the inner crust of a neutron star is further investigated, focusing on the role of the interband response in the superfluid fraction and the effective mass of crustal ions induced by their motion through the superfluid. Calculations are performed within the linear response theory of the self-consistent time-dependent Hartree-Fock-Bogoliubov equations with Skyrme nuclear energy density functionals in the Bardeen-Cooper-Schrieffer approximation. The absence of interband response in previous analyses is clarified. The neutron superfluid density is formally shown to be consistent with the entrainment matrix derived earlier in homogeneous neutron-proton superfluid mixture, thus providing a unified description of entrainment effects in the inner crust and outer core of a neutron star within the same microscopic framework. The relative importance of the intraband and interband responses in different regions of the crust is numerically assessed from three-dimensional band-structure calculations, taking into account quantum zero-point motion of ions about their equilibrium position. The neutron superfluid fraction is found to be enhanced by the interband response, resulting in effective ion masses that remain close to the mass of quantum mechanically bound nucleons for realistic neutron pairing gaps. Results are compared to predictions from classical hydrodynamics with different prescriptions for the permeability of ions to superfluidity.
Comments:
50 pages, 15 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Superconductivity (cond-mat.supr-con); Nuclear Theory (nucl-th)
arXiv:
2605.25600 [pdf]
0 citations
10
[Submitted on 25 May 2026] (cross-list from hep-ph)
Odderon Form Factors in Reggeized Spin-2 Pomeron and Spin-3 Odderon Exchange in $pp$ and $p p ˉ$ Elastic Scattering
Dominador F. Vaso · Jr. · Prin Sawasdipol · Jingle B. Magallanes · Chakrit Pongkitivanichkul · Daris Samart
We investigate the form-factor dependence of Reggeized tensor Pomeron and Odderon exchanges in high-energy elastic $pp$ and $p p ˉ$ scattering. The spin structure is implemented through explicit covariant spin-2 and spin-3 projectors, kept factorized from the Reggeized scalar kernels, so that vertex effects can be separated from trajectory dynamics. Seven Odderon--proton form-factor parametrizations are tested against a global dataset including TOTEM $pp$ data at $s = 2.76$ , $7$ , $8$ , and $13$ ~TeV and Tevatron $p p ˉ$ data at $s = 1.80$ and $1.96$ ~TeV. A clear hierarchy is found. Six dipole, polynomial, Gaussian, and hybrid parametrizations give comparable fit qualities, $χ_{red}^{2} ≃ 1.44$ -- $1.48$ , whereas a one-parameter exponential form, $F_{O} (t) = exp [- B ∣ t ∣/2]$ , yields $χ_{red}^{2} = 0.98$ for 138 degrees of freedom. The fitted couplings and Regge slopes remain comparatively stable across the form-factor choices, indicating that the improvement is driven mainly by the Odderon--proton vertex rather than by large compensating shifts in trajectory parameters. The exponential form admits an impact-parameter interpretation as a Gaussian transverse profile, with an effective radius $⟨ b^{2} ⟩ = 2 B ℏ c$ . The extracted radii are of hadronic size and suggest a peripheral soft Odderon interaction. The shrinking $t$ -range over which the single-Regge-exchange description remains accurate at increasing energy indicates the onset of absorptive and unitarity corrections. These results provide a compact phenomenological framework for connecting the $pp / p p ˉ$ dip--bump difference with the transverse structure of $C$ -odd color-singlet exchange.
Comments:
20 pages, 5 figures, 7 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2605.25636 [pdf]
1 citation
11
[Submitted on 25 May 2026] (cross-list from hep-ex)
Intermittency and fractal behaviour of charged particles in EPOS4 and PYTHIA8 generated events at LHC energies
Fakhar Ul Haider🇮🇳 · Ramni Gupta🇮🇳 · Salman Khurshid Malik🇮🇳 · Balwan Singh🇮🇳 · Zarina Banoo🇮🇳 · Pryianka Choudhary
Large number density fluctuations of the charged particles produced in heavy-ion collisions are a promising signature for exploring the QCD phase transition and critical point in the nuclear matter phase diagram. Intermittency methodology is used to probe the fractal and scale invariant nature of these fluctuations. Intermittency is the phenomenon of power-law growth of the normalized factorial moments ( $F_{q}$ ) of the number density distributions over decreasing bin size. The charged particles generated in the midrapidity region using PYTHIA8 and EPOS4 (UrQMD ON/OFF) for Pb--Pb collisions at $s_{NN}$ = 5.02 TeV are studied. Scaling behaviour of $F_{q}$ are studied as a function of phase space partitioning and second order moments to quantify the particle production nature within the default constraints of the two models. The scaling exponent related to the phase transition and parameters connected to fractal nature obtained for both these models show the absence of fluctuations of critical nature and multifractal behaviour.
Comments:
11 pages, 10 figures
Subjects:
High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2605.25675 [pdf]
0 citations
12
[Submitted on 25 May 2026] (cross-list from astro-ph.HE)
Core-collapse supernovae and supernova neutrinos
B. Mueller🇦🇺 · B. Sykes🇦🇺
Core-collapse supernovae are the terminal explosions of massive stars. After successive phases of nuclear fusion proceeding up to silicon burning, these stars form an iron core that is supported by electron degeneracy pressure. The core eventually collapses to a proto-neutron star, and in most cases the outer layers of the star are ejected by a shock wave, with a kinetic energy of order $1 0^{51} erg$ . Neutrinos and multi-dimensional fluid flow play a key role in extracting energy from the collapsed core to drive the explosion. After adumbrating the astrophysical context of stellar evolution and transient observations, this chapter sketches the modern theory of neutrino-driven supernova explosions, and discusses the key role of nuclear physics and neutrino interaction rates in the supernova problem. It also outlines the role of neutrinos and gravitational waves as probes into the supernova core.
Comments:
23 pages, 8 figures. Preprint of a chapter for the Encyclopedia of Nuclear Physics, section Nuclear Astrophysics (ed. S. Reddy) Typo in title corrected
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:
2605.25879 [pdf]
2 citations
13
[Submitted on 25 May 2026] (cross-list from hep-ph)
Predicted Exotic Doubly Heavy-Strange Pentaquarks
Albert Feijoo🇪🇸 · Eulogio Oset🇪🇸
We predict exotic doubly heavy--strange pentaquarks with minimal quark content $u d ˉ s Q Q^{'}$ ( $Q Q^{'} = cc, b c, bb$ ) within a coupled-channel unitary framework where the interaction is derived from an extension of the local hidden gauge approach to the heavy-quark sector. We obtain a robust spectrum of manifestly exotic states; two states appear in the $u d ˉ scc$ sector, three in $u d ˉ sc b$ , and four in $u d ˉ s bb$ . These emerge either as bound states or resonances, along with five additional virtual states manifested as threshold cusps. The binding mechanism is dominated by off-diagonal transitions among heavy-baryon--light-meson channels, while diagonal interactions are strongly suppressed. These results extend exotic hadron spectroscopy into the doubly heavy--strange sector and provide concrete targets for future experimental searches.
Comments:
8 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2605.25918 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE