An Effective Field Theory Dark Matter Search Using High Energy Nuclear Recoil in the LZ Experiment.

暗物质的存在很好地受到了天体物理学和宇宙学观测的推动，但到目前为止，还没有直接观察到。LuxZeplin(LZ)探测器是世界上最灵敏的液体氙气探测器，其主要物理目标是寻找“弱相互作用物质粒子”(WIMP)暗物质。在一次成功的科学运行1(SR1)之后，科学运行2(SR2)目前正处于数据收集阶段。该项目的主要目标是对SR2数据执行有效场论(EFT)分析：将搜索区域扩展到比标准低能量WIMP搜索更高的反冲能量。这是因为几个更复杂的暗物质相互作用模型预计会在更高的能量下发生。结果要么是发现一个新的暗物质候选粒子，要么是设定世界领先的EFT耦合参数极限。除了主要的分析任务外，还将做出其他几项贡献，包括：升级目前的分析管道，以使用更现代的计算架构，特别是GPU集群；改进模拟，这反过来将改善背景辨别；改进当前的背景模型-很可能使用机器学习。该项目属于支持问题C4的STFC粒子天体物理研究领域-“暗物质和暗能量的本质是什么？”这项研究是作为LuxZeplin合作的一部分进行的。

The existence of Dark Matter is well motivated from astrophysical and cosmological observations but, as yet, has not been observed directly. The LuxZeplin (LZ) detector is the world most sensitive liquid xenon detector with the main physics goal is to search for "weakly interacting matter particle" (WIMP) dark matter. After a successful science run 1 (SR1), science run 2 (SR2) is currently ongoing in the data collection phase.Main objective of this project is to perform an effective field theory (EFT) analysis of SR2 data: extending the search region out to higher recoil energies than standard low energy WIMP search. This is motivated by the fact the several more complex dark matter interaction models are expected to occur at higher energies. The result will be either the discovery of a new dark matter candidate particle, or the setting of world leading limits on EFT coupling parameters.In addition to the main analysis task, several other contributions will be made including: upgrading the currently analysis pipeline to use more modern computational architectures, especially GPU clusters; improving simulations which in turn will improve background discrimination; improvement of current background models - likely with the use of machine learning.The project falls within the STFC Particle Astrophysics research area supporting question C4 - "What is the nature of Dark Matter and Dark Energy?". The research is performed as part of the LuxZeplin Collaboration.