标题： 轻暗物质实验 (LDMX) 显示英文标题

标题： Light Dark Matter eXperiment (LDMX)

摘要： 我们介绍了轻暗物质实验（LDMX）的初步设计研究，LDMX 是一个小规模的加速器实验，在亚GeV质量区域对直接暗物质和媒介粒子产生具有广泛的敏感性。 LDMX 利用多GeV电子核固定靶碰撞中的缺失动量和能量技术，探索电子在未被探索的区域内的耦合，这些区域延伸至并低于由直接热冻结机制所激发的水平。 LDMX 对可见和不可见衰变的暗物质粒子也具有广泛的敏感性，从而解决了2017年美国宇宙愿景暗物质新想法社区报告中强调的许多科学驱动问题。 LDMX 将利用来自CMS、HPS 和Mu2e 实验的现有和正在开发的探测器技术来实现所需的灵敏度。 在本文中，我们展示了我们的初始设计概念、基于GEANT的探测器性能、信号和背景过程的详细研究以及初步分析方法。 我们演示了LDMX的第一阶段如何通过几个数量级扩展到各种轻暗物质、媒介和毫电荷粒子的耦合灵敏度，覆盖广泛的亚GeV质量范围。 显示英文摘要

摘要： We present an initial design study for LDMX, the Light Dark Matter Experiment, a small-scale accelerator experiment having broad sensitivity to both direct dark matter and mediator particle production in the sub-GeV mass region. LDMX employs missing momentum and energy techniques in multi-GeV electro-nuclear fixed-target collisions to explore couplings to electrons in uncharted regions that extend down to and below levels that are motivated by direct thermal freeze-out mechanisms. LDMX would also be sensitive to a wide range of visibly and invisibly decaying dark sector particles, thereby addressing many of the science drivers highlighted in the 2017 US Cosmic Visions New Ideas in Dark Matter Community Report. LDMX would achieve the required sensitivity by leveraging existing and developing detector technologies from the CMS, HPS and Mu2e experiments. In this paper, we present our initial design concept, detailed GEANT-based studies of detector performance, signal and background processes, and a preliminary analysis approach. We demonstrate how a first phase of LDMX could expand sensitivity to a variety of light dark matter, mediator, and millicharge particles by several orders of magnitude in coupling over the broad sub-GeV mass range.