Higher-order QCD perturbation theory in different schemes: From FOPT to CIPT to FAPT

Understand

Results on the resummation of non-power-series expansions of the Adler function of a scalar, $D_S$, and a vector, $D_V$, correlator are presented within fractional analytic perturbation theory (FAPT).

• The first observable can be used to determine the decay width $\Gamma_{H\to b\bar{b}}$ of a scalar Higgs boson to a bottom-antibottom pair, while the second one is relevant for the $e^+e^-$ annihilation cross section.
• The obtained estimates are compared with those from fixed-order (FOPT) and contour-improved perturbation theory (CIPT), working out the differences.
• We prove that although FAPT and CIPT are conceptually different, they yield identical results.