The two-loop electroweak bosonic corrections to sin(2)theta(b)(eff)

摘要

The prediction of the effective electroweak mixing angle sin(2)theta(b)(eff) the Standard Model at two- loop accuracy has now been completed by the first calculation of the bosonic two- loop corrections to the Z (b) over barb vertex. Numerical predictions are presented in the form of a fitting formula as function of M-Z, M-W, M-H, m(t) and Delta alpha, alpha(s). For central input values, we obtain a relative correction of Delta kappa((alpha 2,bos))(b) = -0.9855 x 10(-4), amounting to about a quarter of the fermionic corrections, and corresponding to sin(2)theta(b)(eff)= 0.232704. The integration of the corresponding two- loop vertex Feynman integrals with up to three dimensionless parameters in Minkowskian kinematics has been performed with two approaches: (i) Sector decomposition, implemented in the packages FIESTA 3 and SecDec3, and ( ii) Mellin-Barnes representations, implemented inAMBRE3/MB and the new package MBnumerics. (C) 2016 The Authors. Published by Elsevier B.V.