High Pressure Gas TPCs for Neutrinos

The origin of the large matter-antimatter asymmetry, also called CP violation, in the universe is one of the most fundamental questions facing modern physics. Through our work as convenors and lead analysts for the T2K experiment, which fires particles called neutrinos hundreds of kilometers across Japan, we have played a central role in producing the strongest indications to date of CP violation in neutrino oscillations. CP violation generated by neutrinos, which are neutral, nearly-massless fundamental particles, has the potential to be orders of magnitude larger than the small amounts seen in the quark sector and could be sufficient to explain the observed matter-antimatter difference. Currently, experiments like T2K are limited by the small number of neutrino interactions they are able to collect. However, both of the larger future experiments that are being constructed to definitively observe and precisely characterise neutrino CP violation will for the first time collect enough interactions to be limited by their systematic uncertainties, as opposed to the number of neutrinos observed. We propose a program of detector development and measurements that will provide key inputs needed to address the largest of these systematics, our understanding of the interactions of neutrinos with matter. Specifically, we will use the equipment requested to develop a high-pressure gas time projection chamber (HPgTPC) detector and test it using a beam of protons at the Fermilab test beam facility in the USA, advancing both technology and physics measurements.