# Neutrinos

The observation of neutrino oscillations both solved the solar neutrino puzzle and opened up the possibility of CP violation in the neutrino sector. This will be searched for by the next generation of neutrino experiments which will also study proton decay and astrophysical neutrinos.

Hyper-K is a planned next generation underground water Cherenkov detector situated in Kamioka, Japan. Currently, it is the R&D phase with first running expecting around 2026. It consists of two cylindrical tanks  each with a height of 60 m and diameter of 74 m giving a 520,000 tonne water target. The detector volume is about 10 times larger than the existing Super-Kamiokande (SuperK) detector. On the walls of the tanks, 40,000 ultra-sensitive photo-sensors will be installed,  to detect the Cherenkov light generated in the water.

Hyper-K will serve as the far detector for a long baseline neutrino oscillation experiment planned for the upgraded J-PARC proton synchrotron beam located at Tokai. With a total exposure of 7.50 MW x 107s to the $2.5^{\circ}$ off-axis neutrino beam, Hyper-K aims to make a measurement of the CP (charge-parity) violating phase of the neutrino mixing matrix, $\delta_{CP}$, and to determine the neutrino mass hierarchy through the study of atmospheric neutrinos. It is expected that the CP phase $\delta_{CP}$ can be determined to better than $19^{\circ}$ for all possible values of $\delta_{CP}$ and CP violation can be established with a statistical significance of 3(5)σ for 76(58)% of all possible values of $\delta_{CP}$.

The detector is also capable of observing proton decays, atmospheric neutrinos, and neutrinos from astronomical origins enabling measurements that far exceed the current world best measurements.

## People in Neutrinos

Telephone numbers in the list below are shown as UK numbers. Callers from outside the UK should remove the leading zero and use the UK country code (+44).

NamePositionContact detailsLocationPhoto
Peter ClarkeProfessor
JCMB
5421
Franz MuheimProfessor
JCMB
5422
Steve PlayferProfessor
JCMB
5420/ 5301
Research staff
Greig CowanSTFC Ernest Rutherford Fellow
JCMB
5413
Evangelia DrakopoulouPDRA
JCMB
5414
Matthew NeedhamChancellor's Fellow
JCMB
5411