Tomislav Vladisavljevic (Oxford)
Predicting the T2K neutrino flux
Abstract: The production of intense neutrino beams at accelerator facilities is challenging, and requires exceptional understanding of chains of hadronic interactions initiated within thick targets. Most of T2K neutrinos are produced from in-flight decays of focused pions and kaons, emitted from an extended graphite target (90 cm) bombarded with a 30 GeV proton beam. This talk presents a novel technique for estimating the T2K neutrino flux, which relies on dedicated measurements of the pion yields emitted from a T2K replica target collected with the NA61/SHINE experiment. With the inclusion of the NA61 replica target dataset from 2009, the most precise a priori estimation of the neutrino production for an accelerator-based oscillation experiment has been achieved, with flux uncertainties of ~5% at the T2K signal peak. The unprecedented precision of the T2K flux estimate will be crucial for understanding interactions of neutrinos at the near and far detectors, as the experiment enters the high precision era of oscillation measurements. Future hadron production measurements that could further improve the T2K flux estimate will also be highlighted.