Camillo Mariani (University of Rome, La Sapienza)
In this seminar we report the measurement of the rate of the inclusive pi0 production induced by charged current neutrino interactions in a C8H8 target, at a mean energy of 1.3 GeV in the K2K close detector. Out of a sample of 11606 charged current neutrino interactions we selected 479 pi0 events with two photons reconstructed. We found that the cross section ratio of the inclusive pi0 production to the quasi elastic charged current cross section averaged over the K2K neutrino beam is: sigma-CCpi0/sigma-CCQE = 0.306 +/-0.023 (stat) +/- 0.025 (syst) that shows an excess of 39 +/- 15% (statistical and systematic error added in quadrature) with respect to the prediction of our reference Monte Carlo. Taking the single pion contribution from the CC1pi+ measurement, this result can be interpreted as a measurement of the CC multi pion cross section: sigma-CC-mulipi/sigma-CCQE = 0.465 +/- 0.029 (stat) +/- 0.056 (syst)