Nuclear anapole moment

Crystal anapole moment is composed of the atomic magnetic moments which array in anapole structure [3]. It has the same intrinsic structure as Majorana neutrino [2], If we plant a p decay atom into this anapole lattice, the crystal anapole moment will couple to the nuclear anapole moment of the decaying nuclei. So the emitted electron will be given an additional pseudoscalar interaction by the presence of the crystal anapole moment. Then the emission probability will be increased. This is a similar process to that assumed by Zel dovich [1], The variation of the decay rate may be measured to tell whether the crystal anapole moment has an effect on the p decay or not. 

Indeed, around 1980, first experimental results on atomic parity violation have been reported, in particular measurements of the optical activity of bismuth, thallium and lead vapours as well as measurements of an induced electric dipole (El) amplitude to a highly forbidden magnetic dipole transition (Ml) in caesium. These experiments have nowadays reached very high resolution so that even effects from the nuclear anapole moment, which results from weak interactions within the nucleus, have been observed in caesium. The electronic structure calculations for caesium are progressing to a sub-percent accuracy for atomic parity violating effects and the reader is referred to chapter 9 of the first part of this book [12]. 

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W. C. Haxton, C.E. Wieman Atomic parity nonconservation and nuclear anapole moments. Ann. Rev. Nucl. Part. Sci. Annual Reviews 2001, 261 (2001)... 

The first line in this expression describes the rotational structure with color spin-doubling and the hyperflne interaction of the effective electron spin S with the nuclear spin I. B is the rotational constant, J is the electron-rotational angular momentum, A is the o -doubling constant. The second line describes the interaction of the molecule with the external fields B and E, (A is the unit vector directed from the heavy nucleus to the light one). The last line corresponds to the P-odd electromagnetic interaction of the electrons with the anapole moment of the nucleus described by the constant /ca [40], P,T-odd interaction of the electron EDM de with the interamolecular field, and P,T-odd scalar interactions of the electrons with the heavy nucleus [90]. 

Here, k = 4, 7 = 7/2 and K2 = —0.05 for the valence proton of Cs. Additionally, parity violation in the nucleus leads to to a parity-violating nuclear moment, the anapole moment mentioned above, that couples elec-tromagnetically to the atomic electrons. The anapole-electron interaction is described by a Hamiltonian similar to (103),... 

C. Bouchiat, C. Piketty, Nuclear spin dependent parity violating electron-nucleus interaction in heavy atoms. The anapole moment and the perturbation of the hadronic vector neutral current by the hyperfine interaction, Phys. Lett. B 269 (1991) 195-200. 

There is also nuclear physics interest in parity violation because it plays a role in nuclear structure. A particularly interesting possibility is that weak interactions in nuclei can induce an anapole moment, a P-odd multipole that produces no external field and corresponds in lowest order to a toroidal flow of current within the nucleus. An experiment is under way at Yale University to measure the anapole moment of the Ba nucleus using BaF molecules [36],... 

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