New Approaches to Beyond Standard Model Searches with Colliders and Cosmology

大型强子对撞机（LHC）时代给我们带来了一个难题。标准模型（SM）的扩展与以往一样迫切需要，但到目前为止，没有一个标准预期的信号出现。要解决这一难题，需要从新的角度来看待哪些类型的信号在理论上是有动机的，以及采用新的实验搜索方法。这种挑战和机遇为我的现象学研究提供了统一的主题。******在对撞机中产生的长寿命粒子（llp）通常出现在许多超越SM （BSM）的场景中，可以揭示自然、暗物质和重子生成的秘密。在过去，关注由最小超对称激发的信号意味着llp得到的关注要少得多。这种情况现在正在改变，很大程度上是由于我的工作。我带头在大型强子对撞机研究LLP信号，并与实验学家和理论家合作，帮助确定未来十年BSM搜索的路线图。******从这些研究中诞生了我们的MATHUSLA探测器方案，它可以将LHC对LLP信号的灵敏度提高三个数量级。进展很快，我现在正在帮助领导100多名理论家和实验家的努力，使这一想法成为现实。考虑到MATHUSLA的发现潜力，这项努力的重要性怎么强调都不为过，这使它成为我未来几年的主要关注点。它也代表了加拿大在基本粒子物理领域取得领导地位的独特机会。******希格斯玻色子的发现为SM和BSM物理学开辟了许多令人兴奋的研究途径。******隐藏扇区可能导致大量尚未被探测到的对撞机信号，改变宇宙学，甚至影响天体物理学。理论上，他们的动机有各种自上而下和自下而上的原因，但最近他们解决层次问题的潜力已经成为焦点。在大型强子对撞机中，奇异的希格斯衰变是这些理论的独特入口。中性自然性理论导致了壮观的LLP信号，是他们研究的主要动机，但他们的非微扰动力学，理论紫外补全和宇宙学后果的许多方面还不清楚。******对希格斯粒子的研究也使我们能够开始探索电弱相变，这对我们理解宇宙学至关重要，并且可能在通过电弱重子发生机制解释宇宙的物质-反物质不对称方面发挥作用。这需要引入新的理论工具来处理有限温度量子场论的挑战性方面。只有使计算稳健且与模型无关，我们才能最终发现或排除这些和其他重要的理论观点。******最后，许多BSM场景只能在未来的对撞机上进行探测，阐明这种物理情况将决定未来几十年我们领域的未来。

The Large Hadron Collider (LHC) era presents us with a puzzle. Extensions to the Standard Model (SM) are as urgently needed as ever, but none of the canonically expected signals have shown up so far. Resolving this conundrum requires new perspectives on what types of signals are theoretically motivated and new approaches to experimental searches. This challenge and opportunity provides the unifying theme of my research in phenomenology.******Long-lived particles (LLPs) produced at colliders generically arise in many Beyond SM (BSM) scenarios and could reveal the secrets of naturalness, dark matter, and baryogenesis. In the past, the focus on signals inspired by minimal supersymmetry meant that LLPs received much less attention. This is now changing, in significant part due to my work. I am spearheading research into LLP signals at the LHC and am collaborating with experimentalists and theorists to help determine the roadmap of BSM searches for the coming decade.******Born from these investigations is our MATHUSLA detector proposal, which can increase LHC sensitivity to LLP signals by three orders of magnitude. Progress has been swift, and I am now helping to lead the efforts of over 100 theorists and experimentalists to make this idea a reality. Given MATHUSLA's potential for discovery the importance of this endeavor cannot be overstated, making it a major focus for me in the coming years. It also represents a unique opportunity for Canada to take on a leadership position in fundamental particle physics.******The discovery of the Higgs boson has opened up many exciting avenues of investigation for both SM and BSM physics.******Hidden Sectors can lead to a plethora of as-yet undetected collider signals, modify cosmology and even impact astrophysics. They are theoretically motivated for a variety of top-down and bottom-up reasons, but recently their potential to address the hierarchy problem has come into focus. Exotic Higgs decays are a unique portal to these theories at the LHC. Theories of Neutral Naturalness lead to spectacular LLP signals and are a major motivation for their study, but many aspects of their nonperturbative dynamics, theoretical UV completions, and cosmological consequences are not understood.******Study of the Higgs also allows us to begin probing the Electroweak Phase Transition, which is of fundamental importance for our understanding of cosmology, and may play a role in explaining the universe's matter-antimatter asymmetry via the mechanism of Electroweak Baryogenesis. This requires the introduction of new theoretical tools to deal with challenging aspects of Finite-Temperature Quantum Field Theory. Only by making calculations robust and model-independent can we conclusively discover or exclude these and other important theoretical ideas.******Finally, many BSM scenarios can only be probed at future colliders, and articulating this physics case will determine the future of our field in the coming decades.