Neutrino Interactions, the Universe, and Everything: Renewal

Neutrinos are the most abundant matter particle in the universe – around 100 billion pass through a person’s thumbnail every second – but they very rarely interact. This makes them difficult to study, meaning their physics is relatively little understood. Despite this, neutrinos could be incredibly important to understanding the makeup of our universe, and offer one of the most promising avenues for new fundamental discoveries. We know about three “flavours” of neutrino, and that as neutrinos travel they can change from one flavour to another (a process known as “oscillation”; this discovery was awarded the Nobel Prize in Physics in 2015). Some theories predict that differences in the physics of neutrinos and their antimatter equivalent, antineutrinos, could help explain why the universe is made of matter and not antimatter (or even why it exists at all).
The Deep Underground Neutrino Experiment (DUNE) aims to measure neutrino and antineutrino oscillation with accuracy and precision that have never been achieved before, in order to shed light on these questions. DUNE is currently under construction, anticipated to start taking data in 2029, and will use a detector technology known as liquid argon time projection chambers (LArTPCs). One of the biggest challenges for DUNE’s success will be understanding how neutrinos interact with argon nuclei. Because neutrinos are light, neutral particles they are almost impossible to see directly in particle detectors; we have to study them indirectly through the charged particles produced when a neutrino interacts with nuclei inside the detector. A good understanding of exactly how neutrinos interact is therefore critical to DUNE being able to answer deeper questions about the fundamental properties of these particles and how they might have impacted the evolution of our universe.
My Fellowship is built around a two-part strategy: understand neutrino interactions in currently-running LArTPC experiments MicroBooNE and SBND, and use this knowledge to improve the models used in DUNE. During the initial portion of my Fellowship I made world-first or world-leading measurements of a number of different interaction processes, and updated the DUNE analysis framework to allow for broader variations in the modelling of these processes. I also served as Physics Coordinator for the 193-person MicroBooNE collaboration, overseeing all of the collaboration’s outputs (40 publications with over 1400 citations) since October 2021.
During the renewal of this fellowship, I will make critical developments in particle identification in LArTPC detectors using MicroBooNE data, which will result in another world-first measurement of a neutrino interaction mode that could cause problems for DUNE if not well understood. I will work to update DUNE’s oscillation analysis uncertainty model based on the measurements I have made in MicroBooNE, and make further targeted measurements in MicroBooNE and SBND to fill holes in the existing literature. Together, these developments will position the UK as leaders in the DUNE oscillation analysis when data-taking commences, and ultimately enable DUNE to make new discoveries that could forever change the way we understand the world around us.