New constraint on the existence of the mu+-> e+ gamma decay
hep-ex
/ Authors
MEG Collaboration, J. Adam, X. Bai, A. M. Baldini, E. Baracchini, C. Bemporad, G. Boca, P. W. Cattaneo, G. Cavoto, F. Cei
and 64 more authors
C. Cerri, A. de Bari, M. De Gerone, T. Doke, S. Dussoni, J. Egger, K. Fratini, Y. Fujii, L. Galli, G. Gallucci, F. Gatti, B. Golden, M. Grassi, A. Graziosi, D. N. Grigoriev, T. Haruyama, M. Hildebrandt, Y. Hisamatsu, F. Ignatov, T. Iwamoto, D. Kaneko, P. -R. Kettle, B. I. Khazin, N. Khomotov
/ Abstract
The analysis of a combined data set, totaling 3.6 \times 10^14 stopped muons on target, in the search for the lepton flavour violating decay mu^+ -> e^+ gamma is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 \times 10^-13 (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.