发表机构
UCLouvain（法语鲁汶大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出新观测量：用SMEFT离壳效应与三重积不对称性，以及四顶夸克产生中的标量共振搜索，来探测对撞机上的新物理。
AI 中文摘要
希格斯玻色子的发现巩固了我们所知的粒子物理标准模型（SM），迄今为止的观测也证实了标准模型的预言。如今，为了克服标准模型剩余的缺陷，可以探索过多的超越标准模型（BSM）模型。因此，通用模型提供了一个有用的中间步骤，通过同时探测多个紫外（Ultraviolet）模型来指向标准模型的下一扩展方向。在本工作中，研究了两个例子。首先，在标准模型有效场论（SMEFT）中，通过高维算符提供了潜在重新粒子的离壳效应。特别是，通过在华沙基的CP奇算符上使用U(1)整体味对称性，对威尔逊系数的电荷宇称（CP）对称性破坏贡献进行排序。简单的三重积不对称性被证明对这些SMEFT算符比截面更敏感，并且比实验中常用的大多数观测量更有效。然后，在四顶夸克产生中独立搜索SUC(3)的单态和八重态标量。信号包括标量与顶夸克对的联合产生，以及在八重态情况下产生增强的顶夸克对的成对产生。这些过程在量子色动力学中以次领头阶生成，并采用仔细的重整化程序和正确的圈图选择。利用顶夸克标记技术的改进、主要背景模拟的改进以及一种选择事件的新技术，进行了一次新粒子搜索，以约束新共振态的质量及其与顶夸克的耦合。
英文摘要
The discovery of the Higgs boson cemented the Standard Model of particle physics (SM) as we know it and observations have so far confirmed SM predictions. Now, too many beyond-the-Standard-Model (BSM) models can be explored to overcome the remaining shortcomings of the SM. As a result, generic models present a useful intermediary step to point towards the next extension of the SM probing multiple Ultraviolet models simultaneously. In this work, two examples are investigated. First, off-shell effects of potential heavy new particles are provided in the Standard Model Effective Field Theory (SMEFT) through higher dimensional operators. In particular, Charge-parity (CP) symmetry violating contributions from Wilson coefficients are ranked by using U(1) global flavour symmetries on CP-odd operators of the Warsaw basis. Asymmetries of simple triple products are proven to be more sensitive than the cross-section to these SMEFT operators and more efficient than most of the usual observables used in experiments. Then, on-shell effects of singlet and octet scalars of SUC(3) are independently searched for in four-top production. The signal consists of the associated production of a scalar with a top quark pair and of pair production in the case of the octet producing boosted top-quark pairs. The processes are generated at next-to-leading order in quantum chromodynamics with a careful renormalisation procedure and the correct selection of loop diagrams. Using improvements in top-jet tagging techniques and in the main background simulation as well as a new technique to select the events, a new particle search is performed to constrain the respective mass and coupling to top quarks of new resonances.
Comments243 pages
