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

• Published in: Journal of physics. Conference series Vol. 800; no. 1; pp. 12020 - 12025
• Main Author: Shaikhiev, A. T.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2017
• Subjects: Decay; Kaons; Muons; Neutrinos; Physics
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/800/1/012020

The existence of a heavy neutrino, ν H , in the K + → μ + ν H decays was tested using the E949 experimental data with an exposure of 1.70 × 1012 stopped kaons. The allowed heavy neutrino mass region for the analysis is from 175 MeV/c 2 to 300 MeV/c 2. With major background from the radiative K + → μ + ν μ γ decay understood and suppressed, the preliminary new upper limits (90% C.L.) on the neutrino mixing matrix element between muon and heavy neutrino, |U μ H|2, were set at the level of 10−8 to 10−9. New limit on the K + → μ + ν ν ¯ ν branching ratio assuming Standard Model muon spectrum is set to be 2.4 × 10−6.