New experiment WAGASCI to measure cross sections of neutrino interactions in water and hydrocarbon using J-PARC beam

The main objective of the long base T2K,Tokai-to-Kamioka, Japan, experiment is the investigation of neutrino oscillations with a high-intensity beam of muon neutrinos and antineutrinos. Neutrino interaction measurements in the near detector complex (ND280) of the Т2К experiment are used for adjustment of the parameters defining event simulation in the far detector (Super-Kamiokande), which is the key idea of the experiment; this allows one to considerably increase the oscillation analysis accuracy. The difference in the target material of the far (water) and near (scintillator, hydrocarbon) detectors results in a substantial systematic error in oscillation analysis. Systematic error can be reduced by direct measurements, a new water grid and scintillator detector WAGASCI was proposed for this purpose. The detector will operate at the J-PARC neutrino beam and measure the ratio of charged-current neutrino cross sections between water and hydrocarbon with a few percent precision. Further physical programs may include precise measurements of various charged channels of neutrino interaction. This paper presents the detector concept and the current plan for its installation.