Initial population of μ−, π−, K− after radiative atomic recombination

We calculate the radiative atomic recombination ofμ −,π −,K − with a nucleus. In the initial state the negative particle moves in a Coulomb field, in the continuous spectrum, with positive energy and is captured into the bound orbit (n,l) of negative energy. We consider the exotic atom as a hydrogenic atom. The analytical expression of the recombination cross section, together with a “low energy” approximation, is derived. We obtain information on the atomic initial population: the results presented here show that the Bohr statistical distribution, used in the case of neutral atoms, is not correct in this case.