Accelerator-Based Neutrino Beams

Over the past six decades, accelerator-based neutrino beams have revolutionized particle physics. Neutrinos created with accelerators have been used to discover muon and tau neutrinos and to confirm the existence of neutrino oscillations. More recently, long-baseline experiments have offered the first experimental hint of charge-parity ( CP ) violation in the neutrino sector. Building and operating such beams is an enormous technical challenge, yet they remain our most versatile tool for studying neutrinos. With new experiments such as DUNE (the Deep Underground Neutrino Experiment) and Hyper-Kamiokande, and ideas such as neutrino factories, the next generation of beams will address open questions about neutrino mass ordering, CP violation, and possible physics beyond the Standard Model.