论文标题
\ bbm \在订单$α_s$及以后的宽度差异
The width difference in \bbm\ at order $α_s$ and beyond
论文作者
论文摘要
我们完成了$γ_{12}^Q $的计算，$ b_q- \ bar {b} _q $混合，$ q = d，s $，以订购$α_s$，以订购$α_s$，以列出重量夸克扩展的主要能力。为此，我们计算了涉及两个四夸克企鹅运营商的一环和两层捐款。此外，我们提出了涉及铬磁性操作员以及电流或四夸克企鹅操作员的两环QCD校正。此类贡献是$α_s^2 $的订单，即近代到领先的订单。我们还提出了一环和两环的结果，涉及两个铬磁性操作员，它们分别是近代到接头和近代临时到隔壁到领导阶的正式。通过我们的新更正，我们将获得标准模型预测$δγ_s/δm_s=（5.20 \ pm 0.69）\ cdot 10^{ - 3} $如果$γ_{12}^s $以$ \ + edline Lineelline {\ rm MS} $ b-quark质量表示，同时我们会发现$ b- quark s = 4.770/def 0.96）\ CDOT 10^{ - 3} $而不是用于使用极质量的$。
We complete the calculation of the element $Γ_{12}^q$ of the decay matrix in $B_q-\bar{B}_q$ mixing, $q=d,s$, to order $α_s$ in the leading power of the Heavy Quark Expansion. To this end we compute one- and two-loop contributions involving two four-quark penguin operators. Furthermore, we present two-loop QCD corrections involving a chromomagnetic operator and either a current-current or four-quark penguin operator. Such contributions are of order $α_s^2$, i.e. next-to-next-to-leading-order. We also present one-loop and two-loop results involving two chromomagnetic operators which are formally of next-to-next-to-leading and next-to-next-to-next-to-leading-order, respectively. With our new corrections we obtain the Standard-Model prediction $ΔΓ_s/ΔM_s= (5.20\pm 0.69)\cdot 10^{-3}$ if $Γ_{12}^s$ is expressed in terms of the $\overline{\rm MS}$ b-quark mass, while we find $ΔΓ_s/ΔM_s= (4.70\pm 0.96)\cdot 10^{-3}$ instead for the use of the pole mass.
