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arXiv · 2306.10262

Renormalization group summation and analytic continuation from spacelike to timeline regions

M. S. A. Alam Khan
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Abstract

Analytic continuation of the perturbative series from spacelike to timelike regions is performed using renormalization group summed perturbation theory (RGSPT). This method provides an all-order summation of kinematic ``$π^2$-terms'' accessible from a given order of a perturbative series. The impact of the summation of these terms is studied for Higgs boson decay and electromagnetic R-ratio in the perturbative QCD. Results obtained using RGSPT have improved convergence behavior in addition to significantly reduced renormalization scale dependence compared to fixed-order perturbation theory (FOPT). The higher-order behavior using the Padé approximant is also studied for processes considered.

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M. S. A. Alam Khan. 2023-09-16. Renormalization group summation and analytic continuation from spacelike to timeline regions. https://doi.org/10.1103/physrevd.108.014028

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