Relativistic Quantum Chemistry and Spectroscopy of Pionic Atomic Systems: Hyperfine Structure

The consistent relativistic theory of spectra of the exotic pionic atomic systemsPionic atomic systems on the basis of the Klein-Gordon-Fock equation approach and relativistic many-body perturbation theoryRelativistic many-body perturbation theory (electron subsystem) is applied to studying the hyperfine structureHyperfine structure (HFS) energy and radiative parameters. It is characterized by the simultaneous accounting for the electromagnetic and strong pion-nuclear interactions by means of using the generalized radiation and strong pion-nuclear optical potentials. The nuclear effects are effectively taken into account within the known Gauss and Fermi models. The modified Uehling-Serber approximation is used to take into account for the Lamb shift polarization part. In order to take into account the contribution of the Lamb shift self-energy part it is used an effective non-perturbative procedure, which generalizes the Mohr procedure and radiation model potential method by Flambaum-Ginges. The results of calculation of the contributions (main Coulomb correction, vacuum polarization contribution, etc.) to the energy of the 5 g-4f, 5f-4d transitions, the hyperfine structureHyperfine structure parameters and the transition probabilities between the HFS components in the pion-N atom spectrum etc. are listed. The HFS splitting energies of the 9p level for a number of light, medium, and heavy pionic atoms (13C, 15N, 19F, 20Ne, 57Fe, 129Xe, 133Cs, 175Lu, 205Tl, 202Pb) are listed. The measured values and alternative data based on other versions of the Klein-Gordon-Fock theories with taking into account for the nuclear and radiative correctionsNuclear and radiative corrections are listed too.