中性赝标介子的双轻子衰变  

Dilepton decays of the neutral pseudoscalar mesons

作　　者：余毅聪[1] 

机构地区：[1]中国科学技术大学近代物理系,安徽合肥230026

出　　处：《中国科学技术大学学报》2013年第9期714-722,共9页JUSTC

摘　　要：中性赝标介子(π0,η等)衰变到轻子对的过程一直深受理论和实验关注.这些过程的研究对于检验标准模型和寻找超越标准模型以外的新物理有指导意义.这里首先在手征微扰论的框架下详细分析π0→e+e-,发现该过程的衰变率可以确定至一个未知常数.目前尚无模型无关方法来确定这一个未知常数组合.然后在一个矢量为主的模型中计算这一过程,发现模型中参数的存在使得理论有一定的不确定性.与实验值相比,理论预言的不确定性将会模糊可能的新物理信号,同样的分析可以推广至η→e+e-和η→μ+μ-.The process in which neutral pseudoscalar mesons（π0,η, etc. ） decay to lepton pairs has attracted a lot of attention in both theoretical and experimental aspects. Studies of these processes may help us to test the long-distance dynamics of the Standard-Model and to search for new physics beyond Standard- Model. Here, an analysis was first conducted of the decay channel π→e＋e- in the framework of the chiral perturbation theory, and it was found that its amplitude can be determined up to a combination of some unknown coupling constants. Currently, there is no model-independent method to determine this combination. Then, this process was discussed in a vector meson dominant model. Our theoretical prediction agrees with the data. However, the parameters in this model can bring some uncertainty to the calculation, which might obscure the new physics signal. Similar discussions could be applied to the process of η→e^＋e^- and η→μ^＋μ^-.

关 键 词：中性赝标介子 π0衰变 η衰变 手征微扰论 

分 类 号：O572.24[理学—粒子物理与原子核物理]