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QCD因子化方法下两体非轻无粲_s→VV衰变
Study of Two-Body Non-leptonic Charmless _s→VV Decays within QCD Factorization
【摘要】 利用QCD因子化方法 ,在标准模型下对Bs 介子衰变到两个轻矢量介子的过程进行了分析 .结果表明 :(i)在该方法下 ,非因子化修正对不同的螺旋度振幅的贡献是不同的 ,有效系数ahi 是与末态矢量介子的螺旋度h相关的 ;(ii) Bs→VV过程中的某些衰变道的分支比是很大的 ,甚至达到了10 - 5的量级 ,在未来的B物理实验上是完全有可能测量到的 ;(iii)对大多数衰变道来讲 ,横向衰变宽度与总宽度的比值ΓT/Γ是非常小的 .这意味着在两体非轻 Bs→VV衰变中 ,末态两个轻矢量介子都趋向于具有零螺旋度 .
【Abstract】 Using the method of QCD factorization, we analyse the two-body non-leptonic decays of _s meson into two light vector mesons in the Standard Model. We find: (i) non-factorizable corrections to different helicity amplitudes are different, and effective parameters ah_i are helicity dependent. (ii) the branching ratios of some _s→VV channels are very large, and even reach to the order of 10 -5, which is quite possible to be measured in the future experiments of B physics. (iii) for most decay modes, the transverse decay rate to the total one,Γ_T/Γ, is very small, which implies that both final state light vector mesons in the _s→VV decay tend to zero helicity.
【Key words】 Standard Model; QCD factoriztion; B_s decays; branching ratio; helicity;
- 【文献出处】 高能物理与核物理 ,High Energy Physics and Nuclear Physics , 编辑部邮箱 ,2004年12期
- 【分类号】O571
- 【下载频次】57