Yoshikazu Nagai (U. Colorado) "Understanding Neutrino Beams: Hadron Production Measurements with NA61/SHINE"

ABSTRACT:
A precise prediction of the neutrino flux is a key ingredient for achieving the physics goals of accelerator-based neutrino experiments. In modern experiments, neutrino beams are created from the decays of secondary hadrons produced in hadron-nucleus interactions. Hadron production is the leading systematic uncertainty source on the neutrino flux prediction; therefore, its precise measurement is essential.
The NA61/SPS Heavy Ion and Neutrino Experiment (NA61/SHINE) is a fixed-target experiment at the CERN Super Proton Synchrotron which studies hadron production in hadron-nucleus and nucleus-nucleus collisions for various physics goals. For neutrino physics, light hadron beams (protons, pions, and kaons) are collided with a light nuclear target (carbon, aluminum, and beryllium) and spectra of outgoing hadrons are measured. In this talk, I will present recent results and ongoing analyses of hadron production measurements at NA61/SHINE for precise neutrino flux predictions in the T2K and Fermilab-based long-baseline neutrino experiments. I will also discuss the necessity and prospects of further hadron production measurements for the next generation neutrino experiments with NA61/SHINE beyond 2020, after the Long Shutdown 2 of the accelerator complex at CERN.