Neutrinos are the most abundant matter particles in the universe, but relatively little is known about them. The fact that they are massive particles, unexpectedly discovered via neutrino oscillation, has changed the way we think about neutrinos. Studying the poorly-understood properties of neutrinos could answer many of the great mysteries of physics. Neutrinos could be key to answer the long lasting question of the asymmetry in the universe between matter and anti-matter: why do we live in a matter-dominated universe, when all our theories tell us that matter and matter were created in equal amounts in the Big Bang? Even more strange: we know that matter and antimatter destroy each other when they come into contact, so why does the universe exist at all? Differences in physics between matter and antimatter are known as "violating charge-parity symmetry". It is possible that neutrinos could violate charge-parity symmetry in a significant way - if it is found that they do, neutrinos could be the stepping-stone to the explanation of the Universe imbalance. Many more puzzles also need to be addressed, such as: what are the parameters that dictate neutrino oscillation? Which neutrino type is the heaviest, and which is the lightest (the "mass ordering")? Neutrino oscillation experiments will provide the perfect environment to study these properties and the Oxford group is playing an active role in some of those.
The group is currently involved in the T2K and MicroBooNE experiments. T2K is a long-baseline neutrino experiment that made the first observation of electron-neutrino appearance in 2011. This experiment, located in Japan, is used to study neutrino oscillation as well as neutrino interactions. MicroBooNE is the world's longest-running Liquid Argon time projection chamber, and the largest of these detectors ever built in the US. It has collected over 500,000 neutrino interactions since 2015, with images showing exquisite detail from the liquid argon detector technology. MicroBooNE is studying how neutrinos interact in argon (vital for upcoming experiments using similar detectors, such as the Short Baseline Neutrino program and DUNE), and investigating some intriguing anomalies seen in previous neutrino experiments. Additionally, we are working to measure neutrino cross sections with the MINERvA experiment.
While analysing data from current experiments, the group is already working towards the next generation of experiments that will push even further the limit of our understanding of neutrinos. The DUNE project in the US is a planned experiment that will send neutrinos 1300 km away to a very large scale Liquid Argon detector to study neutrino oscillation with unprecedented sensitivity. The HyperK Experiment in Japan that will have great sensitivity to charge-parity violation. The group is currently working on both these projects.