Hyper-K One-Year Pre-Construction Extension

Lead Research Organisation: University of Sheffield
Department Name: Physics and Astronomy


The Hyper-Kamiokande experiment is the next generation flagship experiment for the
study of neutrino oscillations, nucleon decays, and astrophysical neutrinos. The detector is a third generation
underground water Cherenkov detector. It will serve as the far detector for a long baseline neutrino oscilla-
tion experiment planned for the upgraded J-PARC (Japan Proton Accelerator Research Complex) neutrino
beam as well as a detector capable of observing proton decays, atmospheric neutrinos, and neutrinos from
astronomical origins enabling measurements that far exceed the current world best measurements.
The proposed activities address the core scientific questions in STFC's roadmap 1 : What are the fun-
damental particles? (C1), Is there a unified framework? (C3) What is the origin of the matter anti-matter
asymmetry? (C7) How do the laws of physics work when driven to the extremes? (D1). Because the long
baseline neutrino experiment is capable of addressing these questions it is the highest priority of the neutrino
STFC roadmap. Furthermore, this project is also perfectly aligned with the European Strategy which recog-
nises it importance [2]: Rapid progress in neutrino oscillation physics, with significant European involvement,
has established a strong scientific case for a long-baseline neutrino programme exploring CP violation and
the mass hierarchy in the neutrino sector. CERN should develop a neutrino programme to pave the way for a
substantial European role in future long-baseline experiments. Europe should explore the possibility of major
participation in leading long-baseline neutrino projects in the US and Japan.


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