X-ray yields in protonium and mesic hydrogen

Recent experimental investigations of atomic x rays in protonium have revived interest in the atomic cascade process. Following a calculation of Leon and Bethe, which includes chemical and Auger deexcitation, Stark mixing and annihilation, as well as radiative transitions, we investigate the dependence of the yields of $K$ and $L$ x rays on the target density, and on the hadronic shifts and widths of the $1s$ and $2p$ levels. Numerical results are also given for kaonic, pionic, and muonic hydrogen.