Studies of Elementary Particles

这项提议要求支持在实验室能量最高的实验基本粒子物理方面的研究计划。这两个强子对撞机实验分别是费米实验室的CDF和大型强子对撞机(LHC)的CMS，目前正在瑞士日内瓦的CERN实验室建造。CDF的合作目前正在完成对用于高亮度数据采集的探测器(RUN II)的重大升级，目前计划于2001年3月1日开始。Tevatron能量将从1.8GeV增加到2.0GeV，光度预计将增加一个数量级。约翰·霍普金斯大学的物理学家正在分析目前的数据集(发现顶夸克的数据集)，同时也在升级CDF粒子跟踪系统的硅顶点探测器(SVX II)部分方面发挥了关键作用。这种顶点探测器对所有带电粒子的跟踪都很重要，但对于寻找和测量接近主顶点的次要顶点是必不可少的，这些次要顶点是b夸克衰变的特征。该小组在CDF中的物理研究主要集中在重夸克物理和寻找新粒子，特别是在b夸克衰变、希格斯和超对称性搜索中的混合和CP破坏。CMS实验将是大型强子对撞机的两个综合实验之一。它将在寻找超越标准模型的物理方面开辟一个新的能量前沿，特别是已知粒子的希格斯玻色子和超对称伙伴。许多新的过程涉及具有b夸克的状态。该小组正在努力开发CMS的b夸克顶点探测器能力。顶点检测器将使用小的硅像素来在PP相互作用区域附近提供特殊的位置分辨率。该团队从许多实验(Mark II、SDC、CDF和L3)中获得了超过十年的硅探测器经验。该小组计划将其物理分析工作集中于使用b夸克衰变来研究底部和顶部物理，并搜索电弱对称破缺、希格斯玻色子和超对称现象。L3实验现在正在使用高于W阈值的LEP II数据，允许精确测量W玻色子的性质，最显著的是质量和耦合，并允许搜索新粒子，特别是标准模型和超对称性中的希格斯玻色子。该小组打算继续参与L3数据采集，直至LEP运行结束(预计在2000年秋季)，并打算在2001年年中至年末完成L3分析工作。这个小组将专注于寻找希格斯玻色子，探索标准模型和超对称签名。

This proposal requests support for a research programin experimental elementary particle physics at the highest laboratory energies. The two hadron collider experiments are CDF at the Fermilab Tevatron and CMS at the Large Hadron Collider (LHC) currently being built at the CERN laboratory in Geneva Switzerland. The CDF collaboration is now finishing a major upgrade of the detector for high-luminosity data taking (Run II) with the Main Injector, currently scheduled to begin on 1 March 2001. The Tevatron energy will increase from 1.8 GeV to 2.0 GeV, and the luminosity is expected to increase by an order of magnitude. Johns Hopkins University physicists are analyzing the present data set (from which the discovery of the top quark was made) while also playing crucial roles in upgrading the silicon vertex detector (SVX II) section of the CDF particle tracking system. This vertex detector is important for all charged particle tracking but is essential to find and measure secondary vertices close to the primary vertex that are characteristic of b-quark decays. Physics research in CDF by this group is concentrated on heavy quark physics and searches for new particles, especially mixing and CP-violation in b-quark decays and Higgs and supersymmetry searches. The CMS experiment will be one of two comprehensive experiments at the LHC. It will open a new energy frontier in the search for physics beyond the Standard Model, in particular the Higgs boson and supersymmetric partners of the known particles. Many of the new processes involve states with b-quarks. This group is working to develop the b-quark vertex detector capabilities of CMS. The vertex detector will use small silicon pixels to provide exceptional position resolution near the pp interaction region. This group has over a decade of experience on silicon detectors from many experiments (Mark II, SDC, CDF, and L3). The group intends its physics analysis efforts to be concentrated on using b-quark decays to study bottom and top physics and to search for phenomena on electroweak symmetry breaking, Higgs bosons, and supersymmetry.The L3 experiment is now taking LEP II data above theW+W- threshold, allowing precise measurement of W boson properties, most notably in mass and couplings, and allowing searches for new particles, especially the Higgs boson in both the Standard Model and supersymmetry. The group intends to continue to participate in L3 data taking through the end of LEP running (expected to be fall 2000) and intends to complete L3 analysis work in mid to late 2001. This group will concentrate on the search for the Higgs boson, exploring both Standard Model and supersymmetric signatures.