ATOMIC ALCHEMY - WEAK DECAYS OF MUONIC AND PIONIC ATOMS INTO OTHER ATOMS

The rates of weak transitions between electromagnetic bound states, fo r example, (pi(+) e(-)) --> (mu(+) e(-))nu(mu), and the exclusive weak decay of a muonic atom into an electronic atom, (Z mu(-)) --> (Ze(-)) nu(mu)<(nu)over bar>(e), are calculated. For Z = 80, relativistic effe cts are shown to increase the latter rate by a factor of 50 compared t o the results of a nonrelativistic calculation. It is argued that the conditions for producing the muonic decay in neon gas (Z = 10), where the branching ratio for the decay per captured muon is 1.7 x 10(-9) ca n be realized using cyclotron traps, though the prospect for a practic al experiment seems remote. In lead the same ratio would be approximat ely similar to 1 x 10(-6) In addition to providing detailed informatio n on the high momentum tail of the wave functions in atomic physics, t hese decays of QED bound states provide a simple toy model for investi gating kinematically analogous situations in exclusive heavy hadronic decays in quantum chromodynamics, such as B --> Kgamma or B --> pi e nu.