K2K coherent pion production in SciBar

The search for charged-current coherent pion production induced by neutrinos with a mean energy of 1.3 GeV is described. The data are collected with a fully active scintillator tracking detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed and an upper limit of 0.60×10−2 is set on the cross section ratio of coherent pion production to the total charged-current interaction at the 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.