This book is a revolutionary new method to measure neutrino oscillation parameters in accelerator-based long-baseline experiments, which measure the oscillation of muon neutrinos over hundreds of kilometres. In traditional experiments, the neutrino beam composition is measured with a set of detectors very close to the production point to evaluate the original beam composition and a far detector to evaluate how this composition has changed. To perform these measurements, accurate models of the neutrino flux and their interaction with complex nuclei are required to predict the neutrino spectrum. The near detector is relied upon to constrain the large systematic uncertainties associated with these models.
Dr Hasnip developed a new method using a near detector system that is movable transverse to the beam direction. Sampling the beam at many different off-axis positions, he predicted the neutrino spectrum directly from the near detector data with a much-reduced dependence on the neutrino cross section model. He developed the method in such a way that the disappearance of muon neutrinos as well the appearance of electron neutrinos can be predicted, allowing for the measurement of all the oscillation parameters accessible by long-baseline experiments. It is possible that this approach could substantially reduce the systematic uncertainty in an oscillation measurement.
He developed this so-called PRISM method in the context of the future DUNE experiment, but it will have applications for both short- and other long-baseline experiments. It is an essential tool for oscillation measurements of the next generation of precision experiments. Dr Hasnip developed and implemented these methods in a common analysis structure and educated the collaboration about its advantages. His work convinced the collaboration and funding agencies to enlarge the underground experimental hall and make the near detectors movable, something which originally was not foreseen. This is an impressive piece of work, which will have lasting impact on neutrino oscillation experiments.
