论文标题
达尔文操作员对重夸克的非静态腐烂的贡献
Contribution of the Darwin operator to non-leptonic decays of heavy quarks
论文作者
论文摘要
我们计算出达尔文操作员的贡献（$ 1/m_b^3 $更正），以纳入A $ b $ MESON（$ b^+$，$ b^+$，$ b_d $或$ b_s $）的宽度，源自Quark flavour-flavour-flavour-Changing Transition $ b \ b \ q_1 $ b \ bar q_ q_ q_ q_ 2 $ q_ q_2 q_ 3 $， $ q_3 = d，s $。计算的关键思想是夸克繁殖器在外部gluon场中的局部扩展，包括用gluon场强量张量的协变量词和重夸克膨胀（HQE）的标准技术的术语。我们确认了$ 1/m_b^3 $贡献的先前已知表达式，$ \ ell = e，μ，μ，τ$和$ 1/m_b^2 $ ression for q_1 \ ell \barν_\ ell $，均为$ \ ell = e，ull = e，ull = e，nm。我们发现，这个新术语可以对$ b $ erson的非静态衰减宽度进行大约$ -4 \，\％$的大量更正。对于$ b_d $和$ b_s $ mesons来说，这是对自由b Quark衰减的主要校正，而对于$ b^+$ $梅森，达尔文术语给出了第二重要的校正 - 大约是相位空间空间增强的Pauli Interperience贡献的1/2至1/3。由于终生测量中的实验不确定性很小，因此达尔文项贡献的纳入对于标准模型的精确测试至关重要。
We compute the Darwin operator contribution ($1/m_b^3$ correction) to the width of the inclusive non-leptonic decay of a $B$ meson ($B^+$, $B_d$ or $B_s$), stemming from the quark flavour-changing transition $b \to q_1 \bar q_2 q_3$, where $q_1,q_2 = u, c$ and $q_3 = d, s$. The key ideas of the computation are the local expansion of the quark propagator in the external gluon field including terms with covariant derivative of the gluon field strength tensor and the standard technique of the Heavy Quark Expansion (HQE). We confirm the previously known expressions of the $1/m_b^3$ contributions to the semi-leptonic decay $b \to q_1 \ell \bar ν_\ell$, with $\ell = e, μ, τ$ and of the $1/m_b^2$ contributions to the non-leptonic modes. We find that this new term can give a sizeable correction of about $- 4 \, \%$ to the non-leptonic decay width of a $B$ meson. For $B_d$ and $B_s$ mesons this turns out to be the dominant correction to the free b-quark decay, while for the $B^+$ meson the Darwin term gives the second most important correction - roughly 1/2 to 1/3 of the phase space enhanced Pauli interference contribution. Due to the tiny experimental uncertainties in lifetime measurements the incorporation of the Darwin term contribution is crucial for precision tests of the Standard Model.
