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arXiv · hep-ex/0310060

Search for $π^0 \to ν_μ\barν_μ$ Decay in LSND

L. B. Auerbach·R. L. Burman·D. O. Caldwell·E. D. Church·A. K. Cochran·J. B. Donahue·A. R. Fazely·G. T. Garvey·R. M. Gunasingha·R. L. Imlay·G. Kahrimanis·W. C. Louis·R. Majkic·A. Malik·K. L. McIlhany·W. J. Metcalf·G. B. Mills·D. Rupnik·V. D. Sandberg·D. Smith·R. F. Somodi·I. Stancu·W. D. Strossman·M. Sung·R. Tayloe·G. J. VanDalen·W. Vernon·N. Wadia·D. H. White·S. Yellin·H. Yi
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Abstract

We observe a net beam-excess of $8.7 \pm 6.3$ (stat) $\pm 2.4$ (syst) events, above 160 MeV, resulting from the charged-current reaction of $ν_μ$ and/or $\barν_μ$ on C and H in the LSND detector. No beam related muon background is expected in this energy regime. Within an analysis framework of $π^0 \to ν_μ\barν_μ$, we set a direct upper limit for this branching ratio of $Γ(π^0 \to ν_μ\barν_μ) / Γ(π^0 \to all) < 1.6 \times 10^{-6}$ at 90% confidence level.

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L. B. Auerbach, R. L. Burman, D. O. Caldwell, E. D. Church, A. K. Cochran, J. B. Donahue, A. R. Fazely, G. T. Garvey, R. M. Gunasingha, R. L. Imlay, G. Kahrimanis, W. C. Louis, R. Majkic, A. Malik, K. L. McIlhany, W. J. Metcalf, G. B. Mills, D. Rupnik, V. D. Sandberg, D. Smith, R. F. Somodi, I. Stancu, W. D. Strossman, M. Sung, R. Tayloe, G. J. VanDalen, W. Vernon, N. Wadia, D. H. White, S. Yellin, H. Yi. 2003-10-30. Search for $π^0 \to ν_μ\barν_μ$ Decay in LSND. https://doi.org/10.1103/physrevlett.92.091801

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