Transverse nuclear polarization in muonic 208Pb

In light of the recent finding of the discrepancies between theory and experiment in the Δ2p and Δ3p fine-structure splitting energies of muonic 208Pb, we have studied the effect of the electromagnetic transverse interaction on the nuclear-polarization energy shifts of muonic 208Pb. The reasons for this study are that the electric transverse interaction interferes coherently with the Coulomb interaction giving rise to large nuclear-polarization energy shifts, and that the transverse interaction may give nuclear-polarization energies of different muon-spin dependences from those of the Coulomb interaction. The calculation is based on the transition charge and current densities constructed from the random-phase approximation with the density-dependent contact interaction of Migdal and with particle-hole excitations of nearly a full 3 h ω space. The real part of the Feynman propagator was employed in the electromagnetic transverse interaction. The transverse interaction is found to explain 111 eV of the Δ2p binding-energy anomaly, which is one third of the total discrepancy, while it reduces the Δ3p anomaly by 32 eV. Large portions ofthe discrepancies still remain in both cases.