arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.1832hep-ph
收藏

非相对论性QCD模型中$Q\bar Q$介子的性质

Properties of $Q\bar Q$ mesons in non-relativistic QCD formalism

Ajay Kumar Rai, Bhavin Patel, P C Vinodkumar

摘要:

在NRQCD体系下,用长距离系数和短距离系数研究了$Q \bar Q$介子($Q \varepsilon {c, b}$)的衰变率.长距离系数是通过介子的唯象势模型描述得到的。利用重现$c \bar c$、$b \bar b$和$c \bar b$介子质量谱的模型参数研究了这些介子的衰变宽度。我们提取的质量谱,以及再现各自的径向波函数从不同的潜在的模型,以及从非相对论性的唯象夸克反夸克潜在的类型$V(r)=-\frac{α_c}{r}+A r^ν$,$ν$从0.5到2。利用自旋超精细和自旋-轨道相互作用得到了赝标和矢量介子的质量。在此模型中计算了带有QCD修正的衰变常数,并与其它势模型的衰变常数进行了比较。本文用几种已知的势模型研究了$c \bar c$和$b \bar b$介子的双伽玛和双轻子衰变。这些衰变宽度也计算内的NRQCD形式主义$O(v^4)$通过使用各自的光谱参数的模型。我们对$c \bar c$和$b \bar b$介子衰变的理论预测以及从其它一些势方案得到的结果与实验值进行了比较。利用模型参数计算了$B_c$介子的部分宽度和寿命,与实验值符合较好.

英文摘要:

The decay rates of $Q \bar Q$ mesons ($Q \varepsilon {c, b}$) are studied in the NRQCD formalism in terms of their short distance and long distance coefficients. The long distance coefficients are obtained through phenomenological potential model description of the mesons. The model parameters that reproduces the mass spectrum of the $c \bar c$, $b \bar b$ and $c \bar b$ mesons are employed to study the decay widths of these mesons. We extract the mass spectrum as well as the reproduces the respective radial wave functions from the different potential models as well as from non-relativistic phenomenological quark antiquark potential of the type $V(r)=-\frac{α_c}{r}+A r^ν$, with $ν$ varying from 0.5 to 2. The spin hyperfine and spin-orbit interactions are employed to obtain the masses of the pseudoscalar and vector mesons. The decay constants with QCD corrections are computed in this model as well as in the case of other potential models for comparison. The digamma and dileptonic decays of $c \bar c$, and $b \bar b$ mesons are investigated using some of the known potential models without and with radiative corrections up to the lowest order. These decay width are also computed within the NRQCD formalism up to $O(v^4)$ by making uses of the respective spectroscopic parameters of the models. Our theoretical predictions of the decays of the $c \bar c$, and $b \bar b$ mesons and the results obtained from some of the other potential schemes are compared with the experimental values. The partial widths and life time of the $B_c$ meson are also computed using the model parameters and are found to be in good accordance with the experimental values.

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。

↑