The MATHUSLA Experiment

MATHUSLA 实验

• 批准号: SAPPJ-2022-00033
• 负责人: Robertson, Steven
• 金额: $ 9.11万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762568
• 关键词: MATHUSLA; Experiment

Long lived particles (LLPs) beyond the Standard Model are motivated in many new physics extensions, and may have connections to dark matter, the hierarchy problem, neutrino masses, and baryon asymmetry. Collider-based particle physics experiments are increasingly focusing effort on searches for signatures of non-prompt decays, but the scope of the existing searches is intrinsically limited by the physical size of the detectors and proximity to the collision interaction point. The MATHUSLA experiment is a proposed detector of LLPs to be constructed at the CERN laboratory for operation during the high luminosity LHC period, beginning in approximately 2027. The expected MATHUSLA sensitivity for various well-motivated models, such as hadronically decaying LLPs produced from a Standard Model-like Higgs, improves upon that of the LHC main detectors (ATLAS and CMS) by as much as one or two orders of magnitude. The detector will consist of a large (100m x 100m x 25m), air-filled decay volume located on the surface above, and approximately 100m distant from, the CMS interaction region. MATHUSLA itself is designed in a modular fashion, such that the detector can be built in a staged manner. Each 10m x 10m module will be instrumented with layers of plastic scintillators that are read out by silicon photomultipliers via wavelength-shifting optical fibres. These layers, located at the top and bottom of the decay volume, enable the reconstruction of the trajectories of charged particles from the decays of LLPs produced in the high energy proton-proton collisions of the LHC. Additional precision tracking may be provided by one or more layers of resistive plate chambers. By reconstructing the decay vertex of the LLPs from the decay daughters and exploiting timing information from the scintillators, LLP decay vertices can be reconstructed and distinguished from backgrounds from cosmic rays or penetrating Standard Model particles from the LHC. MATHUSLA will be able to detect and resolve decay vertices from LLPs with masses from the GeV scale all the way up to the weak or TeV scale, and with lifetimes approaching the upper limit of ~0.01 s imposed by Big Bang Nucleosynthesis. Furthermore, in the event of an LLP discovery, a combined analysis of MATHUSLA and CMS data could determine the LLP production mode and decay mode, as well as the LLP and parent particle masses. The Canadian MATHUSLA group currently consists of four faculty members at three Canadian universities (University of Victoria, University of Toronto, and McGill University). This proposal is a first project grant request to fund and expand ongoing research related to the MATHUSLA experiment .

标准模型之外的长寿命粒子（LLP）在许多新的物理学扩展中受到激励，并且可能与暗物质，层次问题，中微子质量和重子不对称性有关。基于对撞机的粒子物理实验越来越多地集中精力寻找非瞬发衰变的特征，但现有的搜索范围本质上受到探测器的物理尺寸和碰撞相互作用点的接近程度的限制。Mathusla实验是一个拟在CERN实验室建造的LLP探测器，用于在大约2027年开始的高光度LHC期间运行。对于各种动机良好的模型，例如从标准模型中产生的强子衰变LLP，预期的MATHUSLA灵敏度比LHC主要探测器（ATLAS和CMS）提高了一到两个数量级。 探测器将由一个大的（100米x 100米x 25米），充满空气的衰变体积组成，位于表面上方，距离CMS相互作用区域约100米。MATHUSLA本身是以模块化的方式设计的，因此探测器可以以分阶段的方式构建。每一个10米x10米的模块将装有多层塑料反射器，这些反射器由硅光电倍增管通过波长移动光纤读出。这些层位于衰变体积的顶部和底部，使得能够从LHC的高能质子-质子碰撞中产生的LLP衰变中重建带电粒子的轨迹。附加的精确跟踪可以由一层或多层电阻板室提供。通过从衰变子体重建LLP的衰变顶点并利用来自衰变子体的定时信息，可以重建LLP衰变顶点并将其与来自宇宙射线或来自LHC的穿透标准模型粒子的背景区分开。MATHUSLA将能够检测和解析LLP的衰变顶点，其质量从GeV尺度一直到弱或TeV尺度，并且寿命接近大爆炸核合成所施加的~0.01 s的上限。此外，在发现LLP的情况下，MATHUSLA和CMS数据的组合分析可以确定LLP的产生模式和衰变模式，以及LLP和母粒子质量。加拿大Mathusla小组目前由加拿大三所大学（维多利亚大学、多伦多大学和麦吉尔大学）的四名教员组成。该提案是第一个项目拨款申请，用于资助和扩大与Mathusla实验相关的正在进行的研究。