Searching for Higgs Boson Pair Production with the ATLAS Experiment at the CERN LHC

对电弱对称性破缺的一个重要测试将是建立希格斯玻色子自耦合（_hhh）的证据，这与希格斯势的形状直接相关。这可以通过测量希格斯玻色子对的产生来实现。欧洲核子研究中心ATLAS和CMS实验发现的125 GeV希格斯玻色子也有可能只是粒子物理标准模型之外理论预测的几种中性带电希格斯玻色子之一。这些理论中的许多都预测存在一个更大质量的希格斯玻色子，它能够衰变成两个更轻的125 GeV希格斯玻色子，这可能会在双希格斯不变质谱中以共振的形式出现。一些超出标准模型的物理学也可以以非共振的方式增强双希格斯产生的横截面。该学生将制定分析策略，寻找两个中性125 GeV希格斯玻色子的产生，然后使用ATLAS Run-3 13.6 TeV质子-质子碰撞数据进行_hhh的测量。搜索将集中在最终状态，其中一个希格斯玻色子衰变成两个tau轻子，另一个希格斯玻色子衰变成一对底夸克。作为这项研究的一个关键要素，学生将参与开发tau轻子识别的算法。该学生还将有机会在ATLAS di-Higgs搜索通道的统计组合中发挥主导作用。也有可能通过协助ATLAS跟踪器升级的硅模块建设来进行实际的探测器工作，ATLAS跟踪器升级计划在大型强子对撞机运行3次之后安装

An important test of the electroweak symmetry breaking would be to establish evidence of the Higgs boson self-coupling (_hhh), which is directly linked to the shape of the Higgs potential. This can be accomplished through a measurement of Higgs boson pair production. It's also possible that the 125 GeV Higgs boson discovered by the CERN ATLAS and CMS experiments is only one of several neutrally-charged Higgs bosons predicted by theories beyond the Standard Model of Particle Physics. Many of these theories predict the existence of a more massive Higgs boson that is able to decay into two lighter 125 GeV Higgses, which could appear as a resonance in the di-Higgs invariant mass spectrum. Some physics beyond the Standard Model could also enchance the di-Higgs production cross-section in a non-resonant manner. The student will develop analysis strategies to search for the production of two neutral 125 GeV Higgs bosons, and then carry out a measurement of _hhh using the ATLAS Run-3 13.6 TeV proton-proton collision data. Searches will focus on a final state where one of the Higgs bosons decays into two tau leptons, and the second Higgs boson decays to a pair of bottom quarks. As a key element of this search, the student will participate in developing algorithms for tau lepton identification. The student will also have the opportunity to play a leading role in the statistical combination of ATLAS di-Higgs search channels. There is also a possibility for hands-on detector work, by assisting with silicon module construction for the ATLAS tracker upgrade which is planned for installation following Run-3 of the LHC