High Pressure Gas TPCs for Neutrinos

宇宙中大物质-反物质不对称（也称为CP违逆）的起源是现代物理学面临的最基本问题之一。通过我们作为T2K实验的召集人和首席分析师的工作，我们在产生迄今为止中微子振荡中最强烈的CP违反迹象方面发挥了核心作用。T2K实验在日本各地发射了数百公里的中微子。中微子是中性的、几乎没有质量的基本粒子，它产生的CP违和可能比在夸克扇区中看到的少量粒子大几个数量级，足以解释观察到的物质-反物质差异。目前，像T2K这样的实验受到他们能够收集到的少量中微子相互作用的限制。然而，未来正在进行的两个更大的实验将首次收集到足够的相互作用，以限制它们的系统不确定性，而不是观察到的中微子数量。我们提出了一个探测器开发和测量计划，它将提供解决这些系统中最大的问题所需的关键输入，即我们对中微子与物质相互作用的理解。具体而言，我们将使用所要求的设备开发高压气体时间投影室（HPgTPC）探测器，并在美国费米实验室测试光束设施中使用质子束进行测试，从而推进技术和物理测量。

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.