When a muon stops in a hydrogen isotope target, it replaces the electron of an atom to form a muonic atom in an excited state. Understanding muonic atom formation and the cascade process to the ground state is important, since they affect muon transfer from excited states (the q1s problem), as well as the creation of hot atoms via acceleration. The sequence is, however, one of the least studied processes in CF , partly due to the lack of direct experimental information. Recent theoretical developments on the formation processes are reviewed in Refs. [5,6,7].
In a simple picture
, the muon is expected to
be captured in an excited orbital state with the principal quantum number
whose wave function has similar
energy and spatial size to that of the ground state electron. In
reality, the target is molecular rather than atomic hydrogen, and muonic
atom formation is predicted to occur via formation of an excited molecule
and its decay, in semi-classical calculations by
Fesenko and Korenman , results in a broad distribution over
quantum states n.
More complete, but quasi-classical
dynamical calculations, including rotational and vibrational degrees of
freedom of the molecule are being carried out by