Hyper-Kamiokande construction

Lead Research Organisation: King's College London
Department Name: Physics


Hyper-Kamiokande will be both a microscope for discovering the properties of neutrinos and a neutrino telescope for observing the cosmos.

Hyper-K's physics goals, aligned with the STFC Science Challenges, require a step-change in intensity, magnitude and precision over current experiments. This is timely as our objectives exceed the capabilities of the current facilities and new larger detectors with a more powerful beam are needed.
We propose to develop key components for data-readout, calibration, an intense neutrino source [if awarded the infrastructure grant] background noise suppression that will create unique scientific opportunities for UK scientists and engineers.

\Hyper-Kamiokande is a large infrastructure for particle physics and astrophysics within the Physical Sciences & Engineering research and innovation spectrum. Its main goal is to make measurements that will help us to understand why there is more matter than antimatter in the Universe. It provides a state-of-the-art, high-precision infrastructure that will be used by scientists from 19 countries to address fundamental scientific questions during its period of operation of at least 20 years from 2027.

The infrastructure consists of three facilities. The first is an accelerator at J-PARC (Japan) capable of producing a very intense beam of neutrinos or antineutrinos. Close to the beam an assembly of detectors (near detectors) and an Intermediate Water Cherenkov detector (IWCD) determine the initial properties of the beam particles. A far detector (also called Hyper-Kamiokande) 295km from the beam source and situated in a deep mine in Tochibora (Japan) measures the changes in the particles' properties in a vast 260kton tank of pure water surrounded by an array of high-performance photosensors (PMTs). Comparing neutrino and antineutrino properties will provide unique information on Charge-Parity (CP) violation that will help to unravel the matter-antimatter asymmetry in the Universe. In addition to the world's most sensitive search for neutrino CP violation, the far detector will provide an unparalleled observatory in which a wide range of physical properties of the Universe will be investigated. They include searches for proton decay, a process not yet observed; the most accurate measurement of neutrinos from supernovae; and the first evidence of relic neutrinos from supernovae in the early Universe.

The accelerator beam upgrade, far-detector excavation and significant parts of the far detector itself were approved in January 2020 by the Japanese government. Hyper-K builds on a successful tradition of water Cherenkov detectors (Kamioka and Super-Kamiokande), with two Nobel Prizes awarded so far. Over the last 15 years, we have been an important part of the success of the T2K and Super-Kamiokande experiments recognised by the award of the 2016 Breakthrough Prize in Physics. We plan to build on this success within Hyper-K, where we play a key role in designing the project. We have strong influence through leadership positions, including one of the two Project Leaders, and plan to play a role in the experiment consistent with our size and experience; we are the largest country in Hyper-K after Japan.

The Hyper-Kamiokande project leverages the important investment the UK has already made in its predecessor T2K and considerable work and accumulated experience in long-baseline experiments as well as leveraging on investments from Japan (around half a billion GBP) as well as other countries.


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