Beyond the Standard Model.. and how to get there

在60年代，理论物理学家已经为粒子相互作用的游戏写下了规则手册：“粒子物理标准模型”。这个模型50多年来一直非常可靠，提供了经过无数次实验检验的精确理论预测。然而，一种被称为“中微子”的粒子打破了规则，它的犯罪行为可以帮助解释为什么宇宙在大爆炸后没有简单地在一道光中消失。此外，天文学家还观察到了一种新的物质--暗物质，它将星系联系在一起。既然我们认为宇宙中的一切都是由粒子组成的，暗物质粒子应该存在，但至少30年来一直没有被实验物理学家发现。这些“罪犯”告诉我们，我们曾经认为的宇宙规则手册实际上只是一本更大的大部头中的一章，不幸的是，阅读起来要难得多。为了这个奖学金，我提出了一个三重计划，将通过创造性地使用液体Argon时间投影室(LArTPC)来探索超越标准模型的物理学。液体Ar时间投影室(LArTPC)是我在过去七年的研究中用来开发和进行世界领先测量的尖端技术。LArTPC已被国际中微子界选中，用于构建该领域的下一个旗舰实验-深层地下中微子实验(DUNE)。沙丘将于2020年代末上线，将通过测量中微子振荡来确定中微子在宇宙开始时的作用：中微子振荡是指电子类型的中微子出现在Muon类型的中微子束中。这种超越标准模型的测量将达到所需的灵敏度，并且只有在我们事先表征电子中微子如何与Ar相互作用的情况下才能成功。我的第一个目标是第一次测量这一特性所需的全面量：电子中微子在Ar中的截面。我将使用Ar上记录的最大的电子中微子相互作用样本来进行搜索--这是来自MicroBooNE实验的数据集，这是表面上一个较小的LArTPC。Microboone不断地暴露在大气层中产生的宇宙µ子的暴雨中，这是一个关键的背景，我将不得不研究并删除它来识别电子中微子；但它有可能成为意想不到的宝藏。事实上，我的第二个目标是对我的第一次分析进行分析，并扫描Muon数据，以寻找人们长期追寻的暗物质粒子的特征。我将使用为我的博士论文开发的方法来执行这项搜索；它在暗物质搜索中的应用以前从未尝试过。如果在介子数据中发现了难以捉摸的暗物质粒子的证据，其影响将是变革性的。我的战略的第三个目标是从技术角度解决超越标准模型物理，突破LArTPC的界限。像沙丘这样的数千吨地下中微子探测器提供了一个独特的机会，可以记录只有比标准模型规则手册更基本的理论才能预测的极其罕见的事件。将创新的像素技术与对非晶态硒和石墨烯的最新研究相结合，这一奖学金将使我能够开发一种传感器，针对这些极其罕见的事件优化LArTPC性能。我提议的研究计划将高影响和新颖的分析与雄心勃勃但具有潜在变革性的技术开发相结合。这项工作勾勒出了一条明确的道路，以确保沙丘在其超越标准模型计划中的成功，同时描述了将在现有数据集上进行的创新暗物质搜索。由于关于超越标准模型的确切实验证据非常难以捉摸，任何超越标准模型的发现都将改变我们对自然的理解。

In the 60s, theoretical physicists had written the rule-book for the game of particle interactions: the "Standard Model of Particle Physics". This model has been very solid for more than 50 years now, providing precise theoretical predictions which have stood experimental test countless times. Yet, a particle called the "neutrino" breaks the rules, and its criminal behavior could help explain why the Universe didn't simply disappear in a flash of light just after the Big Bang. Additionally, astronomers have observed a new type of matter, dark matter, tying galaxies together. Since we think that everything in the Universe is made of particles, dark matter particles should exist, but have eluded experimental physicists for at least 30 years. These "criminals" tell us that what we once thought was the rule-book of the Universe is actually just a chapter in a much bigger tome, unfortunately much harder to read.For this fellowship, I propose a 3-fold program that will open pathways to explore physics Beyond the Standard Model via the creative use of Liquid Argon Time Projection Chambers (LArTPCs) the cutting-edge technology that I spent the last seven years of my research developing and performing world-leading measurements with.LArTPCs have been chosen by the international neutrino community to construct the Deep Underground Neutrino Experiment (DUNE), the next flagship experiment in the field. DUNE, will go live in the late 2020s, is set to identify the neutrino's role at the beginning of the Universe via the measurement of neutrino oscillations: the appearance of neutrinos of the electron type in a beam of neutrinos of the muon type. This Beyond Standard Model measurement will reach the required sensitivity and be successful only if we characterize how electron neutrinos interact with the argon beforehand. My first objective is measuring for the first time the comprehensive set of quantities needed for this characterization: electron neutrino cross sections in argon. I will perform this search using the biggest sample of electron neutrino interactions ever recorded on argon -- a dataset from the MicroBooNE experiment, a smaller LArTPC on the surface. MicroBooNE's constant exposure to a heavy rain of cosmic muons produced in the atmosphere represents a key background which I will have to study and remove to identify electron neutrinos; but it has the potential to become an unexpected treasure. Indeed, the second objective of my fellowship is to pivot my first analyses and scan the muon data for a signature of the long-sought-after dark matter particle. I will perform this search with a method developed for my PhD thesis; and its application to dark matter searches has never been attempted before. If evidence of the elusive dark matter particle is found in the muon data, the impact would be transformational. The third objective of my strategy tackles Beyond Standard Model physics from an technological perspective, pushing the boundaries of the LArTPC. Multi-kiloton underground neutrino detectors like DUNE provide a unique opportunities to register extremely rare events predicted only by theories more fundamental than the Standard Model rule-book. Combining innovative pixel technology with state of the art research on amorphous selenium and graphene, this fellowship will allow me to develop a sensor that optimizes the LArTPC performances for these extremely rare events.My proposed research program incorporates high-impact and novel analyses with an ambitious but potentially transformative technology development. This work outlines a clear path to ensure DUNE's success in its Beyond Standard Model program, while describing innovative dark matter searches to be performed on already available datasets. Since definitive experimental proof of what lies beyond has been extremely elusive, the impact of any Beyond Standard Model discovery would transform our understanding of Nature.