arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0705.1500hep-phhep-ex
收藏

赝标Eta和Eta'介子的组成

Composition of the Pseudoscalar Eta and Eta' Mesons

C. E. Thomas

摘要:

η介子和η '介子的组成长期以来一直是人们讨论的一个来源,随着新的实验结果的出现,这一问题也引起了人们的兴趣。我们研究了从一些不同的过程中可以学到什么:V到P gamma和P到V gamma(V和P分别是光矢量和赝标介子),P到gamma gamma,J/psi,psi'到P gamma,J/psi,psi'到P V,以及chi_{c0,2}到PP。这些限制η-η '混合角到一个一致的值,φ约42度;我们发现,cbar分量的幅度小于5%。我们还发现,虽然数据暗示在一个小的胶子成分的eta ',结论依赖于未知的形状因子与排他性的动力学敏感。此外,我们预测BR(psi'到eta' γ)约为110 ^{-5},BR(chi_{c0}到eta ')约为210 ^{-5}-110 ^{-4}。我们提供了一种方法来测试混合使用chi_{c2}的eta eta,eta“eta”,和eta eta“模式,并作出一些一般性的观察chi_{c0,2}衰变。我们还调查了半轻子和强子衰变的底部和迷人的介子,并找到一些模式的混合角可以提取干净与当前的实验数据,一些更多的数据将允许这一点,和一些更详细的知识,不同的振幅是必需的。

英文摘要:

The composition of the eta and eta' mesons has long been a source of discussion and is of current interest with new experimental results appearing. We investigate what can be learnt from a number of different processes: V to P gamma and P to V gamma (V and P are light vector and pseudoscalar mesons respectively), P to gamma gamma, J/psi,psi' to P gamma, J/psi,psi' to P V, and chi_{c0,2} to PP. These constrain the eta-eta' mixing angle to a consistent value, phi approx 42 degrees; we find that the c cbar components are lesssim 5% in amplitude. We also find that, while the data hint at a small gluonic component in the eta', the conclusions depend sensitively on unknown form factors associated with exclusive dynamics. In addition, we predict BR(psi' to eta' gamma) approx 1 10^{-5} and BR(chi_{c0} to eta eta') approx 2 10^{-5} - 1 10^{-4}. We provide a method to test the mixing using chi_{c2} to eta eta, eta' eta', and eta eta' modes and make some general observations on chi_{c0,2} decays. We also survey the semileptonic and hadronic decays of bottom and charmed mesons and find some modes where the mixing angle can be extracted cleanly with the current experimental data, some where more data will allow this, and some where a more detailed knowledge of the different amplitudes is required.

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。

↑