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Nuclear Theory·nucl-th

Wednesday·March 25, 2026

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    Electroweak Radiative Corrections to Parity-Violating Electron-Nucleus Scattering

    Brendan T. Reed🇺🇸 · C.J. Horowitz🇺🇸

    Parity-violating electron-scattering provides a largely model independent way of measuring neutron densities in nuclei that has important implications for the structure of nuclei and neutron stars. In this paper we calculate radiative corrections to the parity-violating asymmetry in electron-nucleus scattering including vertex and vacuum polarization contributions. We find large cancellations between the vertex corrections to the vector and axial-vector vertices. As a result the total radiative correction in 2nd Born approximation is dominated by vacuum polarization and is of order -0.5\%. Coulomb distortions have modest effects on radiative corrections for C and Ca nuclei. For Pb Coulomb distortions reduce the total radiative correction to only about 0.1\%. Therefore, these corrections are not important for the interpretation of the PREX and MREX experiments on Pb and for the CREX experiment on Ca. However, radiative corrections must be carefully included for a precision measurement of the weak charge of C.

    nucl-thPRC(2026)·2 citations
  2. 02

    Algebraic Nilsson cranking model and its prediction for 20Ne

    Parviz Gulshani · Alaaeddine Lahbas

    Previously, Nilsson-Ragnarsson solved numerically the conventional cranking model (CCRM3) with deformed oscillator potential and spin-orbit interaction (refer to as Nilsson CCRM3) and predicted the 20Ne ground-state rotational-band yrast energies at the angular momenta I=2,4,6, and 8. However, CCRM3 is semi-classical and phenomenological and breaks a number of nuclear symmetries. Recently, we developed, starting from the nuclear Schrodinger equation, a microscopic, quantal, self-consistent cranking model (MSCRM3), where, among other features, the angular velocity is microscopic derived. We solved algebraically the MSCRM3 equations for the pure oscillator potential and used the model to predict energies and rotation types in 20Ne. Some interesting results were obtained, such as the quenching or the transition of planar rotation to a uniaxial rotation thereby reducing the excitation energy at I=8 in 20Ne. In this article, we use the algebraic method developed in our MSCRM3 analysis to solve iteratively the self-consistent Nilsson-CCRM3 Schrodinger equation. The application of this algebraic Nilsson-CCRM3 model to the 20Ne nucleus predicts ground-state rotational-band excitation energies at the angular momenta I=2,4,6, and 8 that are in a much better agreement with the measured energies than those predicted earlier by Nilsson-Ragnarsson using a numerical solution method. This agreement and the predicted excited-state energies at I =4 and 8 that vary periodically with the iteration steps (because of single-particle level crossings) provide a possible explanation for the measured lower yrast-state energies at I =4 and 8 relative to those at the I =2 and 6, somewhat resembling the quenching of planar rotation at I =8 mentioned above. This better agreement may also provide a further indication of the weakness of the pairing correlations in 20Ne.

    nucl-th0 citations
  3. 03

    First \textit{ab initio} calculations of first-forbidden transitions in the reactor antineutrino anomaly

    X. Y. Xu🇨🇳 · Z. Y. Meng🇨🇳 · Z. C. Xu🇨🇳 · F. R. Xu🇨🇳

    Forbidden transitions are important for understanding the reactor antineutrino anomaly. Starting from chiral two- plus three-nucleon forces, we have derived the valence-space effective Hamiltonian and effective operators of first-forbidden transitions using the many-body perturbation theory. 20 dominant first-forbidden transitions have been investigated, which provide important contributors to the reactor antineutrino spectrum anomaly. Calculated values are in reasonable agreement with experimental data. Obtained shape factors exhibit significant deviations from the values approximated with forbidden transitions treated as allowed transitions. The ``5 MeV bump'' observed in the experimental U-fission antineutrino spectrum was discussed with self-consistent shape factors obtained in the present \textit{ab initio} calculations. Unlike phenomenological models that require empirical quenching factors to reproduce -decay data, the present \textit{ab initio} calculations do not need to introduce quenching factors for calculations of the first-forbidden transitions.

    nucl-th0 citations
  4. 04

    Production probability of super-heavy nuclei in fusion

    Ning Wang

    The synthesis of super-heavy nuclei (SHN) through fusion reactions is a critical area of nuclear physics, offering insights into nuclear stability and the limits of the periodic table. However, theoretical predictions of evaporation residue cross sections remain challenging due to large uncertainties arising from complex reaction mechanisms and sensitive model parameters. In this work, a new and analytical formula is proposed for systematically describing the production probabilities of SHN with atomic number , based on barrier tunneling concept. Together with the empirical barrier distribution method for describing capture, an improved model, EBD3, reproduces 64 measured within one order of magnitude, with a root-mean-square deviation of 0.351. The model successfully captures key quantities in fission-like process, including fission barrier height, mass asymmetry, depth of capture pocket and the effective fusion barrier height. Predictions for the synthesis of element 119 are presented, identifying promising projectile-target combinations such as Sc + Cf with a maximum cross section of fb. The maximum cross section falls to fb for Cr + Am at the optimal incident energy of 244 MeV.

    nucl-th0 citations
  5. 05

    Shape Polarization and Quasiparticle Alignment in the [523]5/2 and [642]5/2 bands of Hf

    Rong-Xin Nie · Xue-Hui Ai · Xin Guan · Jie Yang

    Rotational properties of [523]5/2 (h11/2) and [642]5/2 (i13/2) signature partner bands in 169Hf are investigated using the Total Routhian Surface (TRS) method. Experimental data show a distinct signature inversion in the [523]5/2 band at high spin, while the [642]5/2 band exhibits conventional signature splitting. Our analysis identifies a proton subshell gap at Z=72 (beta2 ~ 0.35) that 'locks' the proton core, allowing neutron-driven dynamics to dominate signature staggering. A critical shape bifurcation is identified in the [523]5/2 configuration: the alpha = -1/2 branch remains rigid at high deformation (beta2 ~ 0.32, gamma ~ -10 deg), whereas the alpha = +1/2 branch transitions toward reduced beta2 ~ 0.20 and enhanced hexadecapole deformation. This shift facilitates prompt i13/2 neutron alignment at h-bar omega ~ 0.3 MeV for the alpha = +1/2 branch. Furthermore, the alpha = -1/2 signature enters a gamma-soft regime at high spin (gamma fluctuating between -10 and +10 deg), favoring the unfavored signature and reinforcing the Routhian crossing. In contrast, the [642]5/2 band maintains a stable triaxial shape (gamma ~ -18 deg), preventing inversion. At h-bar omega ~ 0.5 MeV, a "shape-jump" to beta2 ~ 0.38 is predicted for the i13/2 band, signaling the breakthrough of the Z=72 gap and the onset of a highly deformed proton-aligned regime.

    nucl-th0 citations
  6. 06

    Hall Viscosity in the Quark-Gluon Plasma

    Sukrut Mondkar · Giorgio Torrieri🇧🇷 · Matthias Kaminski🇺🇸 · René Meyer

    We study the Hall viscosity of the quark gluon plasma (QGP) created in non-central heavy-ion collisions. In the presence of a strong magnetic field or vorticity, rotational symmetry is broken from O(3) to O(2), allowing for two independent Hall viscosities associated with shear deformations transverse and parallel to the symmetry-breaking direction. We find the corresponding constitutive relations by extending the kinetic-theory mechanism to three spatial dimensions and provide parametric estimates of the Hall viscosities under realistic QGP conditions. Both kinetic-theory and holographic estimates indicate that Hall viscosities are comparable in magnitude to the shear viscosity at zero magnetic field. We further show that Hall viscous stresses at hydrodynamic initialization can be as large as standard viscous corrections and identify observable consequences in flow and event-plane correlations.

    nucl-thhep-phhep-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE