Search for the rare decays K+ → μ+X in E949 experiment

10th International Conference on Kaon Physics

Shaikhiev, A.T.^1

Institute for Nuclear Research RAS, 60 October Revolution Pr. 7a, Moscow

117312, Russia^1

关键词: Branching ratio;    Neutrino mass;    Neutrino mixing;    Rare decays;    Standard model;    Upper limits;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/800/1/012020/pdf
DOI  :  10.1088/1742-6596/800/1/012020

来源: IOP

【 摘 要 】

The existence of a heavy neutrino, vH, in the K+→ μ+vH decays was tested using the E949 experimental data with an exposure of 1:70 × 1012stopped kaons. The allowed heavy neutrino mass region for the analysis is from 175 MeV/c2 to 300 MeV/c2. With major background from the radiative K+→ μ+v μγunderstood and suppressed, the preliminary new upper limits (90% C.L.) on the neutrino mixing matrix element between muon and heavy neutrino, (UμH)2were set at the level of 10-8to 10-9. New limit on the K+→ μ+vvv branching ratio assuming Standard Model muon spectrum is set to be 2:4 7times; 10-6.