Experimental study of muonium-antimuonium conversion at the phasotron of the Joint Institute for Nuclear Research
Gordeev V. A. , Savchenko O. V. , Abazov V. M. , Aleshin N. P., Baranov V. A., Bragin A. N. , Gustov S. A. , Kiselev A. Yu. , Komarov E. N. , Kravchuk N. P. , Mamedov T. N. , Miklukho O. B., Murokhin I. V. , Naryshkin Yu. G. , Sknar' V. A. , Sulimov V. V. , Fursov A. P.
An experimental search has been made for muonium-antimuonium conversion (M->M) in an intense beam of surface muons produced at the phasotron of the Joint Institute for Nuclear Research. A wide-angle magnetic lens was used. This experiment was carried out as a collaboration between St. Petersburg Institute of Nuclear Physics and the JINR. A new method was used. It is based on the detection of high-energy electrons from the decay of the muon of the antimuonium by a wide-aperture magnetic spectrometer. This method provides a high luminosity for the detection of the conversion process, along with a low background. No events associated with the M^>M conversion were detected. A limit WMm< 3.9X 1(T7 (at a 90% confidence level) was established on the probability for the conversion process, with respect to ordinary muon decay. This limit is better than the limit which previously existed by a factor of 1.7 The new value for the muonium-antimuonium conversion constant is GM^<0.\3 ■ GF (90% CL).