Bridging grant application for ATLAS-Canada; Prompt and Long-Lived Particles - Searching for new physics at the Energy Frontier

拟议的研究计划将作为我参加欧洲核子研究中心大型强子对撞机（LHC）的ATLAS实验的桥梁。作为加拿大西蒙弗雷泽大学的一名新教员，这项初始的NSERC发现补助金将资助我启动新的研究计划，然后在2021年的比赛期间，NSERC ATLAS-Canada项目补助金的续期将继续提供资金。这份申请描述了我将在今年启动的项目（一年的申请），并希望在未来五年内实施。这些资金将使我能够建立一个杰出的研究项目，在下一次LHC数据采集期（从2021年开始）之前解决迫在眉睫的挑战，并加强加拿大在世界上最受尊敬的科学努力之一中的作用。标准模型就像牛顿物理学——一个成功的故事：它描述了宇宙中所有可见的物质和所有的力（重力除外），它描述了基本粒子如何获得质量（希格斯机制）。所有的预测都被50多年的实验以极高的精度证实了。这个谜题的最后一块拼图是在2012年添加的：ATLAS和CMS实验发现的希格斯玻色子。现在，我们测试这个标准模型的极限，以找到一个不一致的地方，并确定超越标准模型（BSM）的物理线索。揭示这类线索的一个有希望的方法是将其推进到高能，在那里我们期待一个新的理论自己揭示出来。大型强子对撞机是迄今为止建造的最强大的粒子加速器，为探索高能前沿提供了一个独特的机会。我在这里的主要目标是利用ATLAS探测器寻找长寿命新粒子（LLP）特征的迹象，以揭示宇宙中最大的未解之谜：为什么在早期宇宙中物质比反物质占优势，以及暗物质是什么。寻找这些粒子极具挑战性，因为它们往往不与其他物质相互作用，使它们难以被探测到。在大型强子对撞机上对新物理现象的绝大多数搜索都是在假设新粒子衰变迅速的情况下进行的，即非常接近质子-质子相互作用点。然而，SM中的粒子的寿命(t)跨越了一个巨大的范围，从Z玻色子（t~10-25s）到质子（t~ >1034y）和电子（稳定）。同样，BSM模型通常预测具有不同寿命的新粒子。在探测器内，BSM llp的产生点和衰减点之间可能有宏观的、可检测的位移。它们不寻常的特征为粒子对撞机在下一次数据采集期间发现新的物理现象提供了极好的前景。与此同时，标准的重建算法可能会因为LLP的不寻常性质而精确地拒绝包含LLP的事件或对象，并且需要专门的搜索来发现LLP信号。

The proposed research program will act as a bridge to my participation in the ATLAS experiment at the Large Hadron Collider (LHC) at CERN. As a new faculty member in Canada at Simon Fraser University, this initial NSERC Discovery Grant will fund the initiation of my new research program, which will then continue with funding made available by a renewal of the NSERC ATLAS-Canada project grant during the 2021 competition. This application describes the program that I will initiate during this year (request for one year) and that I expect to carry out within the next five years. These funds will allow me to establish an outstanding research program, address imminent challenges ahead of the next LHC data taking period (starting 2021), and enhance Canada's role in one of the world's most highly regarded scientific endeavors. The Standard Model is like Newtonian physics - a success story: it describes all visible matter in the Universe and all forces (with the exception of gravity), and it describes how elementary particles acquire a mass (Higgs mechanism). All predictions have been verified by experiment with excellent precision for more than 50 years. The last piece to this puzzle was added in 2012: the Higgs boson discovery by the ATLAS and CMS experiments. Now we test the limits of this SM in order to find an inconsistency and ascertain clues about physics Beyond the Standard Model (BSM). One promising way to reveal such clues is to push to high energies, where we expect a new theory to reveal itself. The LHC is the most powerful particle accelerator ever built and provides a unique opportunity to explore this high-energy frontier. My primary objective here will be to use the ATLAS detector to search for signs of long-lived new particle (LLP) signatures in order to shed light on the universe's biggest remaining mysteries: why matter prevailed over antimatter in the early universe and what dark matter is. Searching for these particles is highly challenging, as they tend not to interact with other matter, making them elusive to detection. The overwhelming majority of searches for new physics at the LHC have been performed under the assumption that the new particles decay promptly, i.e., very close to the proton-proton interaction point. However, particles in the SM have lifetimes (t) spanning an enormous range of magnitude, from the Z boson (t~10-25s) through to the proton (t>1034y) and electron (stable). Similarly, BSM models typically predict new particles with a variety of lifetimes. BSM LLPs may have macroscopic, detectable displacements between their production and decay points within the detector. Their unusual signatures offer excellent prospects for the discovery of new physics at particle colliders during the next data-taking period. At the same time, standard reconstruction algorithms may reject events or objects containing LLPs precisely because of their unusual nature, and dedicated searches are needed to uncover LLP signals.