Experimental study of the rare decays [ital K][sub [ital L]][sup 0][r arrow][mu][ital e], [ital K][sub [ital L]][sup 0][r arrow][ital ee], [ital K][sub [ital L]][sup 0][r arrow][mu][mu], and [ital K][sub [ital L]][sup 0][r arrow][ital eeee]

Journal Article · Wed Mar 01 04:00:00 EST 1995 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.51.2061· OSTI ID:6579763

Akagi, T; Fukuhisa, R; Hemmi, Y; Inagaki, T; Ishikawa, K; Kishida, T; Kobayashi, M; Komatsubara, T K; Kuze, M; Sai, F; Sato, T; Shinkawa, T; Suekane, F; Takamatsu, K; Toyoura, J; Yamamoto, S S; Yoshimura, Y ^[1]

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1. Department of Physics, Tohoku University, Sendai 980 (Japan) Department of Physics, University of Tokyo, Tokyo 113 (Japan) Department of Physics, Kyoto University, Kyoto 606 (Japan) KEK, National Laboratory for High Energy Physics, Tsukuba 305 (Japan)

An experiment to search for the [ital K][sub [ital L]][sup 0][r arrow][mu][ital e] and [ital K][sub [ital L]][sup 0][r arrow][ital ee] decays and to measure the branching ratio of the [ital K][sub [ital L]][sup 0][r arrow][mu][mu] decay was performed at the KEK 12-GeV Proton Synchrotron. The single-event sensitivity of the present experiment for these channels was around 4[times]10[sup [minus]11]. No event was observed in the fiducial region for the [ital K][sub [ital L]][sup 0][r arrow][mu][ital e] decay and one event, which could not be distinguished from the background, was observed in the fiducial region for the [ital K][sub [ital L]][sup 0][r arrow][ital ee] decay. The obtained upper limits on the branching ratios at 90% confidence level were [ital B]([ital K][sub [ital L]][sup 0][r arrow][mu][ital e])[lt]9.4[times]10[sup [minus]11] and [ital B]([ital K][sub [ital L]][sup 0][r arrow][ital ee])[lt]1.6[times]10[sup [minus]10]. The branching ratio of the [ital K][sub [ital L]][sup 0][r arrow][mu][mu] decay was obtained to be [7.9[plus minus]0.6 (stat) [plus minus]0.2 (syst)][times]10[sup [minus]9] based on 179 events in the fiducial region. Using 18 events with the effective mass [ital M][sub [ital e]][sup +][ital e][sup [minus]][gt]470 MeV /c[sup 2] in the [ital e][sup +][ital e][sup [minus]] sample for the [ital K][sub [ital L]][sup 0][r arrow][ital ee] decay search, the branching ratio of the [ital K][sub [ital L]][sup 0][r arrow][ital e][sup +][ital e][sup [minus]][ital e][sup +][ital e][sup [minus]] decay was estimated to be [6[plus minus]2 (stat) [plus minus]1 (syst)][times]10[sup [minus]8] for [ital M][sub [ital e]][sup +][ital e][sup [minus]][gt]470 MeV/[ital c][sup 2] and [7[plus minus]3 (stat)[plus minus]2(syst)][times]10[sup [minus]8] for [ital M][sub [ital e]][sup +][ital e][sup [minus]][gt]480 MeV/[ital c][sup 2].

• OSTI ID: 6579763
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 51:5; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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