Binding of Magnetic Monopoles and Atomic Nuclei

The formulation of Grand Unified Theories, which allow magnetic monopole-like solutions [1], has stimulated a wide interest in the search of magnetic monopoles and recently evidence has been claimed of their detection [2]. In view of planning further efforts to confirm the existence of magnetic monopoles, it is useful to know the behaviour of these particles when they reach Earth. With this purpose, in this letter we discuss the existence of bound states of magnetic monopoles and atomic nuclei. We estimate the energy levels and the formation rates of these systems. We also comment on some phenomenological implications of the existence of bound states, mainly in connection with the monopole catalysis of proton decay [31. We consider only electrically neutral monopoles, the case of dyons being treated elsewhere [4]. Only the main results of our investigation will be presented. For an extended discussion of the items touched upon in this letter we refer to a forthcoming paper [51. We consider a monopole with a magnetic charge * qM = e/2e, e = -+1, and a nucleus A N with mass m, spin S = I/2 an.d magnetic moment la = S e k / m . Ti le interaction of the magnetic moment with the field B(R) generated by the monopole,