Collaborative Research: FASER and FASERnu at the Large Hadron Collider

粒子物理学的标准模型是一个成功的理论，它与几十年来涉及弱相互作用、电磁相互作用和强相互作用的实验观测相一致。在大型强子对撞机上发现希格斯玻色子进一步证实了这一成功。然而，标准模型仍然是一个不完整的理论。在大型强子对撞机上对希格斯玻色子性质的精确测量可以提供对超越标准模型（BSM）的新物理学的深入了解。在发现希格斯粒子后的近十年里，没有明确的证据表明BSM来自大型LHC实验。这催生了新的实验来取得突破。这个奖项就是这样一个实验，寻找LHC产生的新形式的暗物质。这个名为FASER（Forward Search Experiment）的实验距离光束相互作用点近半公里，将寻找在各种暗物质理论模型中预测的长寿新粒子。这种远距离探测器涵盖了从大型LHC探测器（如ATLAS和CMS）逃逸的信号，许多模型预测低横向动量转移相互作用将产生新的粒子，如暗光子和轴子样粒子，这些粒子可以在FASER探测器中产生信号。FASER将寻找非常高能量（TeV）的电子正电子对，这些电子正电子对将在FASER带电径迹探测器中留下干净清晰的信号。完整的探测器包括超导体，磁跟踪探测器和热量计，所有这些都使用了从大型LHC探测器借来的技术。这导致通用探测器对各种可能的新粒子敏感。该奖项的一个重要组成部分是开发数据采集系统，触发器和数据分析软件，以收集FASER的数据，并从这些数据中挖掘出新粒子的发现。这个经验丰富的团队预计能够在相对较短的三年数据采集时间内发现新的长寿粒子（如果存在的话）。该团队还将与面向高中生的加州州立数学科学暑期学校（COSMOS）合作，为他们提供FASER数据，以获得高能物理数据分析技术的实践经验。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

The Standard Model of particle physics has been a successful theory, agreeing with decades of experimental observations involving weak, electromagnetic, and strong interactions. The discovery of the Higgs boson at the LHC was further confirmation of this success. However, the Standard Model remains an incomplete theory. The precise measurements of the properties of the Higgs boson at the LHC could provide insight into new physics Beyond the Standard Model (BSM). In the almost ten years since the Higgs discovery, there is no clear evidence of BSM coming from the big LHC experiments. This has spawned new experiments to make a breakthrough. This award is such an experiment, looking for new forms of Dark Matter produced at the LHC. The experiment, FASER (Forward Search Experiment), placed almost half a kilometer away from the beam interaction points, will search for long-lived new particles predicted in various theoretical models of Dark Matter. This far-forward detector covers signals that escape the big LHC detectors like ATLAS and CMS, and many models predict low transverse momentum transfer interactions that would produce new particles like dark photons and axion-like particles that could produce signals in the FASER detector.FASER will look for very high energy (TeV) electron positron pairs which would leave a clean, clear signal in the FASER charged- track detector. The complete detector includes scintillators, magnetic tracking detectors and a calorimeter, all using borrowed technology from the big LHC detectors. This results in a general-purpose detector that is sensitive to a wide variety of possible new particles. A large component of the work in this award is the development of the data acquisition system, trigger and data analysis software needed to collect FASER’s data and dig out of this data the discovery of new particles. This very experienced team are expected to be able to discover new long-lived particles, if they are there, within a relatively short three years of data taking. The team also will work with the California State Summer School for Mathematics & Science (COSMOS) for high school students, giving them FASER data for hands-on experience in high energy physics data analysis techniques.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.