arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0901.3823hep-phhep-exhep-lat
收藏

α_s(M_τ)的功率校正,|V_{us}| m_s

Power corrections to alpha_s(M_τ),|V_{us}| and m_s

Stephan Narison

摘要:

我们重新检查最近的测定从τ衰变的功率校正和面对的结果与现有的QCD谱求和规则(QSSR)。我们的结论是,与QSSR分析相反(QSSR分析得出<alpha_sG^2>=(6.8+-1.3 <$10 ^{-2} GeV^4),τ衰变不是提取胶子凝聚的好地方,因为它有额外的alpha_s^2系数,抑制了它在这个过程中的贡献。由e^+e^-和规则和τ衰变得到的结果:ρ α_s <uu>^2 =(4.5+-0.3 GeV ^6,其中ρ =3.0+-0.2证实了四夸克凝聚体的真空饱和估计值的偏差。SVZ展开之外的“非标准”功率修正(直接瞬子、对偶性破坏和快子胶子质量)在V+A强子τ衰变通道中部分抵消,这给出了α s ^[4]:α s(M_τ)=0.3249(29)_{ex}(75)_{th},导致als(M_Z)|τ =0.1192(4)_{ex}(9)_{th},与alpha_s(M_Z)非常一致(但比之更精确)|_Z=0.1191(27),根据Z宽度和电弱数据的整体拟合,在相同的α_s^4量级上得到。最后,讨论了快子胶子质量在确定|V_{us}|从τ衰变和m_s的τ衰变,e^+e^-和(伪)标量通道的重点。

英文摘要:

We re-examine recent determinations of power corrections from tau-decay and confront the results with the existing ones from QCD spectral sum rules (QSSR). We conclude that contrary to the QSSR analysis, which lead to <alpha_s G^2>=(6.8+-1.3)10^{-2} GeV^4, tau-decay is not a good place for extracting the gluon condensate due to its extra alpha_s^2 coefficient which suppresses its contribution in this process. Results from e^+e^- sum rules and tau-decay: rho alpha_s<uu>^2= (4.5+-0.3)10^{-4}GeV^6, where rho=3.0+-0.2 confirm the deviation from the vacuum saturation estimate of the four-quark condensate."Non-standard" power corrections (direct instantons, duality violation and tachyonic gluon mass) beyond the SVZ-expansion, partially cancel out in the V+A hadronic tau-decay channel, which gives at order alpha_s^4: alpha_s(M_tau)=0.3249(29)_{ex}(75)_{th} leading to als(M_Z)|_tau=0.1192 (4)_{ex}(9)_{th},in remarkable agreement with (but more accurate than) alpha_s(M_Z)|_Z=0.1191(27)obtained at the same alpha_s^4 order from the Z-width and the global fit of electroweak data. Finally, the role of the tachyonic gluon mass in the determinations of |V_{us}|from tau-decay and of m_s from tau-decay, e^+e^- and (pseudo)scalar channels is emphasized.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑