Nuclear polarization in muonic atoms

In a muonic atom, the true muon-nuclear electromagnetic interaction is first approximated by a suitable electrostatic central potential. The neglected dynamical effects are then taken into account by a second order perturbation calculation known as nuclear-polarization correction. The result is a higher muon binding energy as compared to the static muon-nucleus system. For the low-lying muonic levels, the nuclear polarization correction is much more important than the so-called dispersion corrections in elastic electron scattering experiments. Due to the lack of detailed information about nuclear excitation spectra, the nuclear polarization corrections are the least known corrections when calculating muonic energy levels. A good experimental determination of the nuclear polarization effect is therefore of prime importance. This is the aim of the present experiment. Using an anti-Compton spectrometer 90Zr, 140Ce and 208Pb targets have been employed. At present, the analysis of the data is most advanced for μ-90Zr. (Auth.)