Muon-induced nuclear magnetic moments in spinless muonic atoms: a simple estimate

In an attempt to address the long-standing fine-structure puzzle in heavy muonic atoms we investigate the magnetic interaction between a nucleus and its bound muon. A simple estimate shows that the effect is only noticeable for unrealistic nuclear parameters. A further investigation as to the relation of this effect to nuclear polarisation (NP) identifies the interaction as the magnetic dipole part of NP. Motivated by the relative closeness of this simple estimate to rigorous evaluations of NP, we extract effective values for the nuclear magnetic polarisability, a quantity otherwise unknown for all but the lightest nuclei.