Adam J, Bai X, Baldini A M, Baracchini E, Bemporad C, Boca G, Cattaneo P W, Cavoto G, Cei F, Cerri C, de Bari A, De Gerone M, Doke T, Dussoni S, Egger J, Fujii Y, Galli L, Gatti F, Golden B, Grassi M, Graziosi A, Grigoriev D N, Haruyama T, Hildebrandt M, Hisamatsu Y, Ignatov F, Iwamoto T, Kaneko D, Kettle P-R, Khazin B I, Khomotov N, Kiselev O, Korenchenko A, Kravchuk N, Lim G, Maki A, Mihara S, Molzon W, Mori T, Mzavia D, Nardò R, Natori H, Nicolò D, Nishiguchi H, Nishimura Y, Ootani W, Panareo M, Papa A, Piredda G, Popov A, Renga F, Ripiccini E, Ritt S, Rossella M, Sawada R, Sergiampietri F, Signorelli G, Suzuki S, Tenchini F, Topchyan C, Uchiyama Y, Voena C, Xiao F, Yamada S, Yamamoto A, Yamashita S, You Z, Yudin Yu V, Zanello D
Paul Scherrer Institut PSI, CH-5232 Villigen, Switzerland and Swiss Federal Institute of Technology ETH, CH-8093 Zürich, Switzerland.
ICEPP, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Phys Rev Lett. 2013 May 17;110(20):201801. doi: 10.1103/PhysRevLett.110.201801. Epub 2013 May 13.
The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay μ(+) → e(+)γ 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 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.
本文介绍了在寻找轻子味违反衰变μ(+)→e(+)γ的过程中，对一个总计3.6×10(14)个停在靶上的μ子的组合数据集的分析。保罗·谢尔研究所的MEG实验收集的数据显示，与背景预期相比，没有事件过量，并给出了该衰变分支比的新上限为5.7×10(-13)（90%置信水平）。这一限制比MEG之前设定的世界最佳限制严格四倍。
