arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0807.4199hep-phhep-ex
收藏

顶夸克轻子味破坏衰变的模型无关约束

Model-Independent Constraints on Lepton-Flavor-Violating Decays of the Top Quark

Jennifer Kile, Amarjit Soni

备注：
15 pages, 5 figures; v2: slightly revised references, small changes in wording, two results expanded to include 2nd lepton flavor case
发表信息：
Phys.Rev.D78:094008,2008
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

大型强子对撞机即将启动，预计每年将产生$\sim 10^8$ $t\bar{t}$对，这为顶级物理学提供了前所未有的机会。由于人们普遍认为顶夸克对新物理学的影响相当敏感，因此需要对其性质进行详细的研究，包括罕见的衰变。一种可能的、实验上独特的衰变是一个top衰变为一个轻夸克和一个违反味道的轻子-反轻子对。我们使用一个有效的运营商的分析，把模型独立的边界上的贡献的衰变$t\to u e^{\pm} μ^{\mp}$和$t\to c e^{\pm} μ^{\mp}$。我们列举了六维运营商的贡献，这些衰变和不变的标准模型规范组。我们将这些算符分为两类，一类是顶夸克属于SU（2）偶态的算符，因此可以在树水平上对低能过程做出贡献，另一类是顶夸克是右手单线态的算符，只能通过回路图对低能过程做出贡献。我们使用$B$和$K$衰减放置限制这些运营商的系数，但发现，一些仍然不受约束，并可能使顶部衰减的可观察到的贡献。

英文摘要：

The imminent start of the Large Hadron Collider, which is expected to produce $\sim 10^8$ $t\bar{t}$ pairs per year, provides an unprecedented opportunity for top physics. As the top quark is widely expected to be rather sensitive to effects of new physics, a detailed study of its properties, including rare decays, is called for. A possible, experimentally distinctive decay is the case where a top decays to a light quark and a flavor-violating lepton-antilepton pair. We use an effective operator analysis to place model-independent bounds on contributions to the decays $t\to u e^{\pm} μ^{\mp}$ and $t\to c e^{\pm} μ^{\mp}$. We enumerate the dimension-six operators which contribute to these decays and which are invariant under the Standard Model gauge group. We separate these operators into two classes, one with operators where the top quark belongs to an SU(2) doublet and thus can contribute at tree level to low-energy processes, and one class with operators where the top quark is a right-handed singlet and can only contribute to low-energy processes via loop diagrams. We use $B$ and $K$ decays to place limits on the coefficients of some of these operators, but find that several remain unconstrained and could potentially make observable contributions to top decay.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑