Electroweak pseudo-observables and Z-boson form factors at two-loop accuracy
Electroweak pseudo-observables and Z-boson form factors at two-loop accuracy
复制标题
DOI：
10.1007/jhep08(2019)113
复制
发表时间：
2019-06
影响因子：
5.4
通讯作者：
I. Dubovyk;A. Freitas;J. Gluza;T. Riemann;J. Usovitsch
中科院分区：
文献类型：
--
作者：
I. Dubovyk;A. Freitas;J. Gluza;T. Riemann;J. Usovitsch
我们提出了标准模型对与Z玻色子有关的一整套唯象相关的电弱精密伪观测量的预测：轻子和底夸克的有效弱混合角，Z玻色子部分衰变宽度，其中f表示任何带电轻子、中微子和夸克味（顶夸克除外），以及总Z衰变宽度Γ Z、分支比R、R c、R B和强子横截面。输入参数是质量MZ、MH和mt以及耦合α s、α。本文还讨论了由于选择MW或其替代G μ作为最后输入参数而引起的方案依赖性。最近在闵可夫斯基大质量高阶费曼积分计算方面取得了实质性的技术进展，可以计算所有提到的观测量的完整的电弱双回路辐射校正。QCD贡献被适当地包括在内。结果提供了简单方便的参数化公式，其系数已确定从全数值多回路计算。估计了丢失的电弱三圈或QCD高阶修正的大小。我们简要地评论其计算的前景。最后，给出了矢量和轴矢量形状因子的直接预测，包括讨论单独的顺序顺序的贡献。
We present Standard Model predictions for the complete set of phenomenologically relevant electroweak precision pseudo-observables related to the Z-boson: the leptonic and bottom-quark effective weak mixing angles,, the Z-boson partial decay widths Γ f, where f indicates any charged lepton, neutrino and quark flavor (except for the top quark), as well as the total Z decay width Γ Z, the branching ratios R ℓ, R c, R b, and the hadronic cross section. The input parameters are the masses M Z, M H and m t, and the couplings α s, α. The scheme dependence due to the choice of M W or its alternative G μ as a last input parameter is also discussed. Recent substantial technical progress in the calculation of Minkowskian massive higher-order Feynman integrals allows the calculation of the complete electroweak two-loop radiative corrections to all the observables mentioned. QCD contributions are included appropriately. Results are provided in terms of simple and convenient parameterization formulae whose coefficients have been determined from the full numerical multi-loop calculation. The size of the missing electroweak three-loop or QCD higher-order corrections is estimated. We briefly comment on the prospects for their calculation. Finally, direct predictions for thevector and axial-vector form-factors are given, including a discussion of separate order-by-order contributions.