Nuclear Theory·nucl-th

Monday·April 20, 2026

12 papers—4 primary·8 cross-listed

01
Novel microscopic approaches for Spin-Isospin excitations and Beta-decay
Hiroyuki Sagawa
We explore unsolved nuclear structure problems related with the spin and isospin degree of freedom by using microscopic models which accommodate realistic isoscalar and isovector pairing interactions, and also tensor correlations. For the attempt of universal theoretical framework for both nuclear and astrophysical phenomena, we adopt a self-consistent Hartree-Fock (HF)+random phase approximation (RPA) models, and a state-of-the-art beyond mean field model, Subtracted Second RPA (SSRPA), including the couplings to two-particle two-hole states. The quenching problems of magnetic dipole and Gamow-Teller transitions are discussed in terms of the coupling to 2p-2h configurations and also the tensor correlations. The $β$ decay life time of semi-magic and magic nuclei are discussed in RPA and SSRPA models.
nucl-thEPJ Web Conf.(2026)·0 citations
02
Charge radii of Sn isotopes in the relativistic mean field approximation
S. Marcos · N. Sandulescu · R. Niembro
The kink observed in the nuclear charge radius of Sn isotopes around neutron number $N = 82$ is investigated within the relativistic mean-field (RMF) framework using the NL3 $^{*}$ parameter set. It is shown that the small components of the Dirac spinors for the neutron single-particle states near the Fermi level play a crucial role in forming the kink through their contribution to the proton central potential. In particular, the significant differences between the radial parts of the small components of spin-orbit partner states make neutrons with $j = l - 1/2$ more efficient in increasing the nuclear charge radius than those with $j = l + 1/2$ . However, the effect induced by the small components alone does not fully account for the magnitude of the kink observed in Sn isotopes.
nucl-thPRC(2026)·0 citations
03
Charged-current quasielastic-like neutrino scattering from $^{12}$ C in the coherent density fluctuation model with two-nucleon emission
M. V. Ivanov🇧🇬 · A. N. Antonov🇧🇬
The quasielastic cross-sections of charged-current neutrino and antineutrino scattering on $^{12}$ C are calculated using the coherent density fluctuation model with a relativistic effective mass $m_{N}^{*} = 0.8 m_{N}$ (CDFM $_{M^{*}}$ ). The model explicitly considers the modification of the relativistic effective mass of the nucleon within the relativistic mean field (RMF) model of nuclear matter. In addition, our calculations include neutrino-induced two-particle emission processes, which are evaluated within the RMF model of nuclear matter. Utilizing the CDFM $_{M^{*}}$ , we provide predictions for the neutrino and antineutrino cross sections of $^{12}$ C, which have been observed in accelerator experiments, such as MiniBooNE, T2K, and MINERvA. Also, we analyze the axial form factor value for the excitation of the $Δ$ at zero momentum transfer (commonly denoted as $C_{5}^{A} (0)$ ) which is important for the treatment of the $Δ$ current in the meson-exchange currents (MEC) calculation. In addition, the quasielastic results obtained within CDFM $_{M^{*}}$ model are thoroughly evaluated for different regions of the momentum transfer.
nucl-thPRC(2026)·0 citations
04
Sensitivity of the $^{3, 4}$ He( $K^{-}$ , $π^{0}$ ) production ratio to the $Λ$ binding energy of $_{Λ}^{3}$ H
Toru Harada🇯🇵 · Yoshiharu Hirabayashi🇯🇵
We study the production of $_{Λ}^{3}$ H and $_{Λ}^{4}$ H in the $^{3, 4}$ He( $K^{-}$ , $π^{0}$ ) reactions at $p_{K^{-}} = 1.0$ ~GeV/ $c$ within the distorted-wave impulse approximation, using the optimal Fermi-averaged $K^{-} p \to π^{0} Λ$ amplitude. Because the $_{Λ}^{3}$ H ground state is extremely weakly bound, the $d$ -- $Λ$ wave function becomes spatially extended. We calculate the integrated cross sections $σ_{lab}$ and their ratio $R_{34} = σ_{lab} (_{Λ}^{3} H) / σ_{lab} (_{Λ}^{4} H)$ for forward angles $θ_{lab} = 0^{\circ}$ -- $2 0^{\circ}$ . The production strength of $_{Λ}^{3}$ H and the ratio $R_{34}$ are strongly sensitive to the $Λ$ binding energy $B_{Λ}$ , which is constrained to be approximately 0.05--0.15~MeV by comparison with experimental data from the J-PARC E73 experiment. This indicates that the $^{3}$ He( $K^{-}$ , $π^{0}$ ) reaction provides a sensitive probe of the weak binding of $_{Λ}^{3}$ H.
nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Novel microscopic approaches for Spin-Isospin excitations and Beta-decay

Charge radii of Sn isotopes in the relativistic mean field approximation

Charged-current quasielastic-like neutrino scattering from 12C in the coherent density fluctuation model with two-nucleon emission

Sensitivity of the 3,4He(K−, π0) production ratio to the Λ binding energy of Λ3​H

Affiliations

Charged-current quasielastic-like neutrino scattering from $^{12}$ C in the coherent density fluctuation model with two-nucleon emission

Sensitivity of the $^{3, 4}$ He( $K^{-}$ , $π^{0}$ ) production ratio to the $Λ$ binding energy of $_{Λ}^{3}$ H