Measurement of the branching ratio of the decay $\Xi^{0}\rightarrow   \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}$
  From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 $\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}$ candidates with a background contamination of $30.8 \pm 4.2$ events.   From this sample, the BR($\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}$) is measured to be $(2.17 \pm 0.32_{\mathrm{stat}}\pm 0.17_{\mathrm{syst}})\times10^{-6}$. 
J.R. Batley, G.E. Kalmus, C. Lazzeroni, D.J. Munday, M. Patel, M.W.   Slater, S.A. Wotton, R. Arcidiacono, G. Bocquet, A. Ce...
hep-ex