Research in Elementary Particle Physics

基本粒子物理研究

• 批准号: 0456688
• 负责人: Mark Oreglia
• 金额: --
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0456688&HistoricalAwards=false
• 关键词: Research; Elementary; Particle; Physics

The Chicago High Energy Physics Group is engaged in three major experiments, ATLAS, CDF and KTeV, and concluding a fourth, OPAL. In addition, the group is planning a reactor neutrino experiment and is continuing work toward a Linear Collider. Each of these subgroups is integrated into the larger whole with the shared goals of understanding Electroweak Symmetry breaking, CP violation, and the basic structure of space-time. Education and outreach are integrated into this effort, with involvement in programs at the elementary, high school, undergraduate, and public levels. The ATLAS experiment at the CERN LHC is expected to begin operation during the period of this request. It will be the world's premier facility for exploring the high energy frontier with the most obvious physics targets being the mechanism for mass generation (Higgs boson) and the explanation of the mass hierarchy (supersymmetry). The Chicago group is involved in calorimetry and is also developing a proposal for a hardware track trigger that will allow rapid selection of events containing b quarks or tau leptons. The CDF experiment at Fermilab is studying ppbar collisions with the world's highest energy accelerator. CDF has made precise determinations of the top quark and W boson masses, and broad searches for physics beyond the Standard Model. Run II is in progress, with the goal of collecting 50 times more data than in Run I. The Chicago trigger electronics is working well and we are now working on Run IIb trigger/DAQ upgrades. Studies of top quark properties and searches for new physics are underway, with the first Chicago Run II papers submitted for publication.The KTeV experiment at Fermilab was designed to measure direct CP violation in Kpp decays and search for very rare K decay modes. The Chicago-led analysis of half of the total KTeV data yielded a 7-sigma observation of direct CP violation; the group is now completing the (e/e) analysis using the full data sample. Among dozens of other results from KTeV, the most notable is the recent determination of |Vus| by the Chicago group based on measurements of KL branching fractions and semileptonic decay form factors. These measurements show very large deviations from previous world averages and are consistent with unitarity of the CKM matrix.Over its lifetime, LEP was the world's premier facility for studies of the electroweak interaction. On the OPAL experiment, the Chicago group was heavily involved in both the detector and physics analysis. In the past few years, Chicago physicists completed a measurement of the W boson mass, searched for non-standard Higgs boson decay modes, and studied semileptonic b decay. New initiatives for the group include a significant new effort in neutrino physics. Chicago has helped form a collaboration of several universities to perform an experiment at a nuclear reactor to measure theta13, the last unmeasured mixing angle of the neutrino mixing matrix. Design studies are underway. Work is also in progress toward an international linear collider, both in the organizational effort and in detector R&D.

芝加哥高能物理小组进行了三个主要实验，即Atlas，CDF和KTEV，并结束了第四个OPAL。此外，该小组正在计划一个反应堆中微子实验，并正在继续向线性对撞机进行工作。这些亚组中的每一个都集成到较大的整体中，以理解电动对称性破坏，违反CP和时空的基本结构的共同目标。教育和外展活动纳入了这项工作，并参与了小学，高中，本科和公立级别的计划。 CERN LHC的ATLAS实验预计将在此请求期间开始运行。最明显的物理目标是探索高能量边界的世界首要设施，是质量产生的机制（Higgs Boson）和质量层次结构的解释（超对称性）。芝加哥集团参与了量热法，并正在为硬件轨道触发器开发一项建议，该提案将允许快速选择包含B夸克或tau leptons的事件。 Fermilab的CDF实验正在研究世界上能量加速器最高的PPBAR碰撞。 CDF已精确地确定了顶级夸克和W玻色子质量，并广泛搜索了标准模型以外的物理学。 Run II正在进行中，其目标是收集50倍的数据，而芝加哥触发电子产品运行良好，我们现在正在进行运行IIB触发/DAQ升级。对顶级夸克特性和对新物理的搜索进行的研究正在进行中，首次提交了芝加哥Run II论文出版。Fermilab的KTEV实验旨在测量KPP衰变中的直接CP违规行为，并寻找非常罕见的K衰减模式。芝加哥主导的一半KTEV数据的分析得出了对直接CP违规的7 sigma观察。该组现在使用完整的数据样本完成（E/E）分析。在KTEV的数十个结果中，最值得注意的是| vus |的最新确定。芝加哥组基于KL分支分数和半衰减衰减形式的测量。这些测量值显示出与以前的世界平均值非常大的偏差，并且与CKM矩阵的单位性一致。从其寿命中，LEP是世界上研究Electroweak相互作用的首要设施。在蛋白石实验中，芝加哥组参与了检测器和物理分析。在过去的几年中，芝加哥物理学家完成了W玻色子质量的测量，搜索了非标准的Higgs玻色子衰变模式，并研究了半蛋白质的B衰变。该小组的新举措包括在中微子物理学方面做出的重大新工作。芝加哥帮助建立了几所大学的合作，以在核反应堆上进行实验，以测量theta13，这是中微子混合矩阵的最后一个未测量的混合角。设计研究正在进行中。 在组织努力和检测器研发方面，工作也正在朝着国际线性撞机方向发展。