  Experimental searches for lepton-flavor-violating coherent muon-to-electron
conversion in the field of a nucleus, have been proposed to reach the
unprecedented sensitivity of 10^(-16) - 10^(-18) per stopped muon. At that
level, they probe new interactions at effective-mass scales well beyond 1000
TeV. However, they must contend with background from ordinary bound muon decay.
To better understand the background-spectrum shape and rate, we have carried
out a detailed analysis of Coulombic-bound-state muon decay, including nuclear
recoil. Implications for future experiments are briefly discussed.
