Preparatory phase for Hyper-Kamoikande long baseline neutrino experiment

Lead Research Organisation: University of Liverpool
Department Name: Physics


The recent discovery of the Higgs boson at the LHC was a major technical and scientific triumph, but it is not the end of the story. There are still many unanswered questions in particle physics. Of these, perhaps the most intriguing is the question of why there is more matter in the Universe than antimatter. If this wasn't the case essentially all the particles would have annihilated with their antiparticle partners and the Universe would be a very different place; there would be no large-scale structure and we wouldn't be here to answer this question.
There must be some explanation for this matter-antimatter asymmetry, and what ever the answer, it implies that "CP is violated", i.e. matter behaves slightly differently from antimatter. CP violation has been observed in the decays of strongly interacting particles, but this is not sufficient to explain the matter-dominated Universe. However, there are indications that neutrinos might provide the answer through a process called lepto-genesis. CP violation in the neutrino sector could represent the next major discovery in particle physics.

Neutrinos are neutral "ghost" particles that hardly interact with matter. When the travel over large distances they change their nature, a process called neutrino flavour oscillations, whereby one type of neutrino oscillates into a different type. CP violation for neutrinos would imply that these oscillation rates are slightly different for neutrinos and antineutrinos. Observing this difference is the next big challenge to experimental particle physics.

The LBNE experiment is the flagship of the future US particle physics programme. It is designed to discover CP violation for neutrinos. A powerful beam of neutrinos will be fired 1300 km from Fermilab, near Chicago, towards a huge underground detector in South Dakota. This underground detector will contain 50,000 tons of liquid argon at a temperature of 87 K (-186 degree Celsius). The liquid argon technology enables neutrinos to be detected with "photograph-quality" detail, marking a breakthrough in neutrino experiments.

In this proposal, UK physicists are requesting £2.5M over three years to take leading roles in the LBNE experiment and to develop the liquid argon detector technology. This research and development phase will allow the UK to be the leading non-US partner in this incredibly exciting experiment.

Planned Impact

Please refer to the impact summary given in the joint proposal Q2017804


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Description The question of why the universe is matter dominated when equal amounts of matter and antimatter were created in the big bang is one of the key questions in science. Hyper Kamiokande will search for differences in neutrino oscillations between neutrinos and antineutrinos, known as CP violation, to help answer this question. This grant is aiding us move towards this experiment.
Exploitation Route We are working on an optical calibration system for the experiment. We have been joined in this work by the LZ experiment and are co-operating towards an improved design for both experiments.
Sectors Other

Description Hyper-K Preconstruction Grant
Amount £1,650,000 (GBP)
Funding ID ST/R000239/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 10/2017 
End 09/2019