标准模型中的稀有半轻子衰变B_s→K■^+■-

Rare Semileptonic Decays B_s→K■^+■^- in the Standard Model

采用手征流关联函数改进的光锥QCD求和规则(LCSR)方法,消掉了3扭度和5扭度K介子波函数的贡献,计算了-6<q2<12范围的Bs→K矢量形状因子fB+s→K(q2)和张量形状因子fBTs→K(q2).进而采用z级数参数化形式拟合LCSR的结果,将其解析延拓至整个半轻子运动学区域.利用获得的形状因子形状,预言了标准模型下稀有半轻衰变Bs→K■+■-(■=e,μ)的q2分布和衰变分支比.

A chiral correlator modified QCD light cone sum rule （LCSR） approach, in which the contributions can-cel out from the twist-3 and-5 wavetunctions of K meson, is empioyeo to calculate the r,Bs→K ＋ and f^bS→k-（q^2） in the region-6 〈 q^2 〈 12. Then fitted to a z-series parameterization, the resulting form factors are extrapolated analytically to the whole semileptonic region. In the framework of standard model, a prediction is made for the q^2 distributions and the decay branching ratios of Bs→k^e＋e^-（e=e,μ）.