Revision of Analytical Properties of Reaction Amplitude near Thresholds Using the Example of Muon-Induced Prompt Fission

Experimental data on the muon-induced prompt fission are analyzed and compared to theory. Good agreement is observed for the 2p to 1s and 3d to 1s transitions. Anomalously big nonradiative width in the case of 3d to 1s transition is surprised. Ways of resolving this puzzle are discussed.