Physics at the LHC with CMS

20世纪的主要智力成就之一是粒子物理标准模型(SM)的发展。这个模型成功地将当时已知的所有基本粒子归入具有相似量子性质的群组的层次结构中。最近在欧洲核子研究中心的大型强子对撞机上发现的希格斯玻色子证实了这个模型到目前为止的有效性。然而，目前存在的标准模型留下了许多关于宇宙的问题，包括为什么希格斯质量具有它的价值这样的基本问题。大型强子对撞机(LHC)是在瑞士日内瓦附近的欧洲核子研究中心实验室运行的首屈一指的能源前沿粒子加速器。它目前是回答这些超越标准模型问题和研究希格斯玻色子性质的最重要的设施之一。大型强子对撞机上的紧凑型介子螺线管(CMS)实验的主要功能之一是发现超越标准模型的新物理。这里提出的工作将分析来自CMS实验的数据，以寻找超越标准模型(BSM)物理的信号。该奖项将资助CMS实验的两个方面：1)进一步搜索BSM物理；2)帮助建立CMS第一阶段正向像素探测器(FPix)，这将增强CMS发现BSM物理的能力。BSM理论预测包括所谓的超对称(SUSY)理论中的几个不同的新粒子。这些新粒子是暗物质的候选者。这一奖项将资助通过衰变到多个轻子(电子或µ子)和喷流(夸克的实验签名)来寻找超对称。在这些通道中的超对称粒子衰变还包括一个超对称粒子，它直接穿过探测器而没有相互作用，因此该事件具有丢失的能量。通过对2010-2013年大型强子对撞机数据的分析，许多SUSY模型已经被排除在外。随着大型强子对撞机在2015年夏季开始运行新的更高能量，新的分析技术将被应用，以便从大背景中分离出SUSY(或其他暗物质候选者)信号。这涉及到矢量玻色子融合(VBF)的生产模式，其中夸克-夸克碰撞产生一对矢量玻色子(W或Z)，然后相互作用(引信)形成新的粒子。这种VBF产生的实验特征是探测器相反半球的一对正向高能喷流，具有大的双喷流质量。这些喷流突出于SM粒子衰变的背景之上，从而在可能发现BSM粒子时提高了信号背景比。该奖项还提供了FPix升级的重要部分，这些部分正在费米拉实验室进行测试。CMS前向像素升级将允许精确的顶点位置，这是所有物理研究所需的，即使在不久的将来运行大型强子对撞机所预期的恶劣环境(非常高的光度)中也是如此。CMS Forward Pixel探测器使用最先进的硅技术进行颗粒检测，并结合同样复杂的读出电子设备。目前的探测器采用了抗辐射技术和凸点键合的创新技术，以满足高辐射环境下的房地产挑战。这些技术将大大延长用于外层空间研究的探测器的寿命，并改进用于医疗应用的生物传感微型设备。

One of the major intellectual achievements of the 20th century was the development of the Standard Model (SM) of particle physics. This model succeeded in classifying all of the elementary particles known at the time into a hierarchy of groups having similar quantum properties. The validity of this model to date was recently confirmed by the discovery of the Higgs boson at the Large Hadron Collider at CERN. However, the Standard Model as it currently exists leaves open many questions about the universe, including such fundamental questions as to why the Higgs mass has the value it has. The Large Hadron Collider (LHC) is the premier Energy Frontier particle accelerator operating at the CERN laboratory near Geneva Switzerland. It is currently one of the foremost facilities for answering these Beyond the Standard Model questions and studying the properties of the Higgs boson. One of the primary functions of the Compact Muon Solenoid (CMS) experiment at the LHC is to discover new physics beyond the Standard Model. The work proposed here will analyze data from the CMS experiment looking for signals of Beyond the Standard Model (BSM) physics. This award will fund two aspects of the CMS experiment: 1) further searches for BSM physics and 2) help build the CMS Phase I forward pixel detector (FPix) upgrade, which will enhance the ability of CMS to discover BSM physics. BSM theoretical predictions include several different new particles in the so-called Super Symmetric (SUSY) theory. These new particles are candidates for Dark Matter. This award will fund searches for SUSY via the decays to multiple leptons (electrons or muons) and jets (the experimental signature of quarks). The SUSY particle decays in these channels also include a SUSY particle that goes right through the detector without interacting, thus the event has missing energy. Many SUSY models have been ruled out by the analysis of LHC data from 2010-2013. With the new higher energy running at LHC starting summer 2015, new analysis techniques will be applied in order to separate out SUSY (or other Dark Matter candidates) signals from large backgrounds. This involves the Vector Boson Fusion (VBF) mode of production where the quark-quark collision produces a pair of vector bosons (either W or Z) which then interact (Fuse) to form new particles. The experimental signature of this VBF production is a pair of energetic jets in the forward direction in opposite hemispheres of the detector, with large di-jet mass. These jets stand out above background from SM particle decays and thus enhance the signal to background ratio in the possible discovery of BSM particles. The award also provides important parts of the FPix upgrade which are being tested at FermiLab. The CMS Forward pixel upgrade will allow the precise vertex location, needed for all physics studies, even in the harsh environment (very high luminosity) expected in near future LHC running. The CMS Forward Pixel Detector uses state-of-the art silicon technology for particle detection combined with equally sophisticated readout electronics. Innovative techniques of radiation hard technology and bump bonding have been used in the current detector to meet the real estate challenges in a high radiation environment. These techniques would greatly enhance the life span of detectors used in outer space research and improve bio-sensing miniature devices for medical applications.