The T2K experiment in Japan sends a beam of neutrinos from the J-PARC accelerator complex in Tokai on the east coast to the Super-Kamiokande detector at Kamioka, 295 kilometres away in western Japan. The aim is to understand how neutrinos change, during their journey, from one of the three neutrino types to another by a quantum phenomenon called neutrino oscillations. The NA61/SHINE experiment at CERN measures the production of charged pions and kaons out of a thin carbon target (4% of a nuclear interaction length) and a replica of the T2K target (a 90-centimetre graphite cylinder) to allow for precise calculations of the initial neutrino fluxes and beam composition at J-PARC (for more details see this article). This leads to the best possible estimate of several neutrino properties, such as neutrino mixing angles, and provides first constraints on the CP-violation phase.
A reach programme of hadron production measurements will albo be performed for Fermilab neutrino beams (see here)