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The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas,
i.e.
particle, nuclear and atomic, is ...reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.
We study the nuclear Schiff moments of 129Xe and 199Hg induced by the nucleon electric dipole moment using large-scale shell model calculations. For 129Xe, we find a linear relation between the ...leading-order contribution and magnetic moment, which would be useful in reducing the theoretical uncertainty. The conventional model space does not contain the 0g9/2 and 0h9/2 orbitals, which are connected to the spin-orbit partners by large matrix elements. Thus, to evaluate the influence of the relevant single-particle orbitals outside the conventional model space, we apply the quasiparticle vacua shell model method. Moreover, the next-to-leading-order contribution arises from parity and time-reversal violation in the nucleus. We demonstrate that these secondary effects do not induce any significant disturbance to the correlation. Additionally, we report the shell model results for the nuclear Schiff moment coefficients of 199Hg. Compared to previous studies, the results obtained in this study are rather large, indicating a higher sensitivity to the neutron electric dipole moment.
Abstract
We propose a simple and versatile model for Λ hypernuclei in medium- and heavy-mass regions to obtain their low-lying energy levels and electromagnetic transitions. In this model, we treat ...the core nucleus as a simple indivisible union of nucleons, and its properties are considered based on the experimental data. The interaction between nucleons in the core and a Λ particle is assumed to be weak and is treated perturbatively. We study medium- and heavy-Λ hypernuclei, i.e.,
Λ
51
V,
Λ
52
V,
Λ
89
Y,
Λ
139
La, and
Λ
208
Pb. To check the applicability of the model to a lighter hypernucleus, we apply it to
Λ
19
F, where
γ
-ray transitions have been experimentally observed. The present study demonstrates that the low-lying excited states of the core nucleus below 2 MeV, in addition to the ground state of the core nucleus have to be considered in the calculation of spectra and electromagnetic transitions in the low-lying states of Λ hypernuclei. The proposed model helps us theoretically study specific medium- and heavy-hypernuclei where large-scale shell-model studies are intractable to carry out.
Abstract
Large-scale nuclear shell-model calculations are performed in the neutron- and proton-deficient Pt, Au, Hg, and Tl isotopes ($Z < 82$ and $N \le 126$) near $^{208}$Pb. All the ...single-particle levels in the one-major shells, six neutron ($2p_{1/2}$, $1f_{5/2}$, $2p_{3/2}$, $0i_{13/2}$, $1f_{7/2}$, and $0h_{9/2}$) orbitals and five proton ($2s_{1/2}$, $1d_{3/2}$, $0h_{11/2}$, $1d_{5/2}$, and $0g_{7/2}$) orbitals are considered. For an effective two-body interaction, one set of the multipole pairing, quadrupole–quadrupole interactions is employed for all the nuclei considered. These phenomenological interactions are determined to reproduce the experimental energy spectra. Some of the isomeric states are analyzed in terms of the shell-model configurations. Octupole correlated states are discussed in terms of a collective octupole excitation on top of each shell model state.
The nuclear matrix elements (NMEs) for the 0 ββ decays from 130Te to 130Xe and from 136Xe to 136Ba are calculated in the nuclear shell model. In order to investigate the model dependence on the NMEs, ...pair-truncated shell-model calculations are also performed. It is found that the NMEs are sensitive to the ground-state correlations. In particular, the isovector monopole-pairing interactions largely affect the NMEs.
Abstract
Masses and radii of neutron stars are obtained in the presence of strong magnetic fields together with rotation. Mass-radius relations are calculated using 11 equations of state (EoSs: GM1, ...TM1-a, TM1-b, TM2$\omega\rho$-a, TM2$\omega\rho$-b, NL3-a, NL3-b, NL3$\omega\rho$-a, NL3$\omega\rho$-b, DDME2-a and DDME2-b) in relativistic mean field (RMF) theory. Obtained masses are over and around twice the solar mass ($M_\odot$) for all EoSs in the presence of strong magnetic fields of $3 \times 10^{18}$ G at the center. For NL3$\omega\rho$-a and NL3$\omega\rho$-b EoSs, masses are more than $M=2.17\,M_\odot$(observed maximum mass: $2.14\,M_\odot$) even without magnetic fields. Rotational effects are found to be insignificant in any case, at least up to the Kepler frequency. Suitable EoSs are also selected concerning the constraint on the radius of a neutron star.
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