Constraints from high energy completion on low-energy effective field theories.

Sumer Jaitly的博士学位将围绕粒子物理学，宇宙学和引力的标准范式之外的物理学。Sumer将首先推导出新型的有效场论，这些理论可以以与观测兼容的方式描述宇宙的暗成分（暗物质，暗能量），并且不仅仅涉及标量自由度。他的研究的一个重要方面将集中在从有效场论的观点一致性的问题。他还将专注于描述粒子物理标准模型之外的物理学的不相关算子。然后，他将推导和利用新类型的正性边界，允许对低能有效理论施加约束。的因果关系，洛伦兹不变性，局部性和高能量完成的酉性的要求施加强有力的约束的行为的低能量散射振幅，这是现在很好地理解为2-2过程。将这些界限扩展到2-2散射之外并探测更大类的高阶算子仍然是一个长期存在的问题，这将是Sumer博士论文的重要组成部分。特别是，他将探讨更高的散射过程，这将使他了解哪些积极的条件可以施加基于更高的散射振幅的扩展曼德尔斯特拉姆相空间的解析性。

Sumer Jaitly's PhD will be centred around physics beyond the standard paradigms of particle physics, cosmology and gravity. Sumer will first derive new types of effective field theories that can describe the dark components of the Universe (dark matter, dark energy) in a way compatible with observations and involving more than just scalar degrees of freedom. An essential aspect of his research will be centred around the question of consistency from an effective field theory viewpoint. He will also focus on the irrelevant operators that describe physics beyond the standard model of particle physics. He will then derive and utilize new types of positivity bounds that allow to impose constraints on the low-energy effective theories. The requirement of causality, Lorentz-invariance, locality and unitarity of the high energy completion imposes strong constraints on the behaviour of the low-energy scattering amplitudes which are by now well-understood for 2-2 processes. Extending those bounds beyond 2-2 scattering and probing a much larger class of higher-order operators has remained a long-standing question which will be an essential part of Sumer's PhD thesis. In particular, he will explore the analyticity of the extended Mandelstram phase space for higher scattering processes which will allow him to understand which positivity conditions can be imposed based on higher scattering amplitudes.