SUSY and dark matter searches using the ATLAS detector

散射实验支配着我们对自然现象的研究。我们的眼睛通过光的散射进行观察。了解它的行为允许显微镜和望远镜被建造，胡克和伽利略用来揭示细胞生物学和外星卫星的隐藏结构。这就奠定了实证研究的基础：通过测量来探测已知的现象，就可以建造仪器来揭示自然界中未知的部分。大型强子对撞机（LHC）的科学也不例外。显微镜的现代化身是人类历史上最复杂的散射实验。位于瑞士和法国边境的欧洲核子研究中心，它的发现可以深刻地加深我们对宇宙中物质和力的空间和时间的理解，这就是本文的主题。大型强子对撞机以世界上最高的13 TeV动量中心能量散射质子束。ATLAS探测器利用基于各种固相、液相和气相技术的跟踪、量热和μ子系统测量产生的碎片，从而能够实施内容丰富的物理方案。这类散射实验利用了相对论和量子力学的两个显著特征：1）物质-能量等价性使得能够产生新的不同粒子，2）粒子-波二象性开启了亚原子结构的非光学探针。几十年的实验和理论工作调和了这两种图像，最终形成了粒子物理学的标准模型（SM）。这一原则性和预测性的理论继续描述所有在对撞机上观察到的现象，并取得了显著的成功。然而，作为对自然的基本描述，标准模型有许多缺点。本论文中最紧迫的两个问题是：a）基本参数的微调结构，和B）没有可行的粒子来解释观测到的天体物理暗物质。一类解利用超对称性扩展了SM的时空对称性。这预示了SM粒子的伙伴，它们的自旋相差半个单位，并且可以在LHC中获得。两个互补的实验项目为这些新现象寻找证据：1）在能量前沿实证检验相对论和量子力学的一致性，2）直接寻找新现象，以揭示自然界未被探索的领域。

Scattering experiments govern our study of natural phenomena. Our eyes make observations via the scattering of light. Understanding its behaviour allowed microscopes and telescopes to be built, which Hooke and Galileo used to unveil then hidden structures of cellular biology and extraterrestrial moons. This set the basis of empirical enquiry: making measurements to probe known phenomena allows the construction of instruments to reveal unknown sectors of nature. The science at the Large Hadron Collider (LHC) is no exception. This modern incarnation of the microscope is the most sophisticated scattering experiment in human history. Situated at CERN on the Swiss-French border, its discoveries could profoundly deepen our understanding of space and time to the matter and forces in our universe, which is the subject of this thesis. The LHC scatters proton beams at the world's highest centre-of-momentum energies of 13 TeV. TheATLAS detector measures the resulting debris using tracking, calorimetry and muon systems based on a variety of solid, liquid and gaseous phase technologies, enabling a rich physics programme. This class of scattering experiment exploits two striking features of relativity and quantum mechanics: 1) matter-energy equivalence enables production of new distinct particles, and 2) particle-wave duality opens non-optical probes of subatomic structures. Decades of experimental and theoretical work reconciled these two pictures, culminating in the Standard Model (SM) of particle physics. This principled and predictive theory continues to describe all observed phenomena at colliders with remarkable success.However, as a fundamental description of nature, the Standard Model has numerous shortcomings. Two of the most pressing addressed in this thesis are a) the fine-tuned structure of fundamental parameters, and b) no viable particle to explain the observed astrophysical dark matter. One class of solutions extends spacetime symmetries of the SM using supersymmetry. This predicts partners of SM particles which differ by half a unit - 1 - of spin and are accessible at the LHC. Two complementary experimental programmes seek evidence for such new phenomena: 1) empirically testing the consistency of relativity and quantum mechanics at the energy frontier, and 2) directly searching for new phenomena to reveal unprobed sectors of nature.