Experimental Studies of Broken Symmetries with Muons, Pions and Photons

μ子、π介子和光子破缺对称性的实验研究

基本信息

批准号：
0072200
负责人：
Tim Gorringe
金额：
$ 40.86万
依托单位：
University of Kentucky Research Foundation
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2000
资助国家：
美国
起止时间：
2000-06-01 至 2004-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0072200&HistoricalAwards=false
关键词：
Experimental Studies Broken Symmetries Muons

项目摘要

0072200Gorringe Quantum chromodynamics (QCD) is the accepted theory of thestrong interactions of quarks and gluons. At low energies the quarksand gluons are confined in baryons (three quarks) and mesons(quark--antiquark pairs), and understanding the properties andinteractions of baryons and mesons in terms of QCD is of fundamental importance. QCD possess a number of elementary symmetries. They include isospin symmetry, whereby the interactions are unaltered by u,d quark flavor rotations, and chiral symmetry, whereby the interactions are unaltered by separate flavor rotations for left, right handed quarks. The realization of these symmetries is rich and varied, involving so-called spontaneous, explicit and anomalous symmetry breaking effects. Understanding their realization is central to understanding the low energy interactions of baryons and mesons. This experimental research addresses the manifestation of symmetries in low energy processes. At the TRIUMF Laboratory in Vancouver, Canada we are investigating chiral and isospin symmetries with beams of muons and pions. For example the weak interaction between muons and protons is a key test of chiral symmetry breaking and the strong interaction between pions and protons is central to understanding the breaking of isospin. In addition, at the Jefferson Laboratory in Newport News, Virginia we are collaborating on a precision measurement of the decay rate of the neutral pion - a unique test of anomalous symmetry breaking in QCD.

0072200Gorringe量子染色体动力学（QCD）是夸克和胶子的thestrong相互作用的公认理论。在低能量下，夸克和胶子被限制在重子（三个夸克）和介子（Quark-antiquark对）中，并了解QCD的Baryons和Mesons的性质和互相是至关重要的。 QCD具有许多基本对称性。它们包括同种对称性，在这种对称性上，相互作用不改变u，d夸克风味旋转和手性对称性，因此，相互作用不会被左，右手夸克的单独风味旋转而改变。这些对称性的实现丰富而多样，涉及所谓的自发，明确和异常的对称性破坏效应。了解它们的认识对于理解重子和介子的低能相互作用至关重要。这项实验研究探讨了低能过程中对称性的表现。在加拿大温哥华的Triumf实验室，我们正在调查手性和同胞的对称性。例如，muons和质子之间的弱相互作用是手性对称性断裂的关键测试，而乳头和质子之间的强相互作用对于理解同胞蛋白的破裂至关重要。此外，在弗吉尼亚州纽波特新闻的杰斐逊实验室中，我们正在与中性锥子的衰减速率进行精确测量，这是QCD中异常对称性破坏的独特测试。