论文标题
来自改进的$τ$矢量等级光谱函数的强耦合
The strong coupling from an improved $τ$ vector isovector spectral function
论文作者
论文摘要
我们结合了以$τ\toπ^-π^0ν_τ$，$τ\ to2π^-π^+π^0ν_τ$和$τ\toπ^-3π^0ν_τ$（i II）的结果（ii）估计的ii f t ii the k^k^-yt t t t ii t to）的光谱分布和蛋白石结果。使用CVC和电气导量数据获得的HADRONIC $τ$ -DECAY模式，以获得新的，更精确的非震撼，包含矢量，等异载体光谱函数。 Babar $ k^-k^0 $和CVC/电气塑性结果为我们提供了替代，完全基于数据的输入，以供所有独家模式的Aleph和Opal使用的蒙特 - 卡洛估计值的贡献。我们使用所得的光谱函数来确定$α_s（M_τ）$，该功能采用有限的能量总规则，以$τ$质量尺度的强耦合。使用固定顺序扰动理论（FOPT）处方，我们发现$α_s（m_τ）= 0.3077 \ pm 0.0075 $，这对应于五量味结果$α_s（m_z）= 0.1171 \ 0.1171 \ pm 0.0010 $ 0.0010 $ in $ z $质量。虽然我们还使用轮廓改良的扰动理论（CIPT）提供了估计值，但我们指出，FOPT处方是与其他$ \ +叠加{\ rm MS} $方案的其他$α_s$确定的比较，特别是考虑到CIPT与最近的标准运营商产品扩展之间的不可或缺的情况下，最近的{\ rm MS} $方案都可以进行。对主要$2π$和$4π$模式的其他实验输入将允许进一步改进当前分析。
We combine ALEPH and OPAL results for the spectral distributions measured in $τ\toπ^-π^0ν_τ$, $τ\to 2π^-π^+π^0ν_τ$ and $τ\toπ^-3π^0ν_τ$ decays with (i) recent BaBar results for the analogous $τ\to K^- K^0ν_τ$ distribution and (ii) estimates of the contributions from other hadronic $τ$-decay modes obtained using CVC and electroproduction data, to obtain a new and more precise non-strange, inclusive vector, isovector spectral function. The BaBar $K^- K^0$ and CVC/electroproduction results provide us with alternate, entirely data-based input for the contributions of all exclusive modes for which ALEPH and OPAL employed Monte-Carlo-based estimates. We use the resulting spectral function to determine $α_s(m_τ)$, the strong coupling at the $τ$ mass scale, employing finite energy sum rules. Using the fixed-order perturbation theory (FOPT) prescription, we find $α_s(m_τ)=0.3077\pm 0.0075$, which corresponds to the five-flavor result $α_s(M_Z)=0.1171\pm 0.0010$ at the $Z$ mass. While we also provide an estimate using contour-improved perturbation theory (CIPT), we point out that the FOPT prescription is to be preferred for comparison with other $α_s$ determinations employing the $\overline{\rm MS}$ scheme, especially given the inconsistency between CIPT and the standard operator product expansion recently pointed out in the literature. Additional experimental input on the dominant $2π$ and $4π$ modes would allow for further improvements to the current analysis.
