Eur. Phys. J. C (2020) 80: 649
https://doi.org/10.1140/epjc/s10052-020-8234-x

Regular Article - Theoretical Physics

Revisiting the bottom quark forward–backward asymmetry in electron–positron collisions

¹ Department of Physics, Guizhou Minzu University, Guiyang, 550025, People’s Republic of China
² Department of Physics, Chongqing University, Chongqing, 401331, People’s Republic of China
³ Max Planck Institute for Physics, Föhringer Ring 6, 80805, München, Germany
⁴ School of Physics and Electronics, Hunan University, Changsha, 410082, People’s Republic of China

^* e-mail: sqwang@cqu.edu.cn

Received: 1 April 2020
Accepted: 11 July 2020
Published online: 21 July 2020

Abstract

The bottom quark forward–backward asymmetry is a key observable in electron–positron collisions at the peak. In this paper, we employ the Principle of Maximum Conformality (PMC) to fix the -running behavior of the next-to-next-to-leading order QCD corrections to . The resulting PMC scale for this is an order of magnitude smaller than the conventional choice . This scale has the physically reasonable behavior and reflects the virtuality of its QCD dynamics, which is independent to the choice of renormalization scale. Our analyses show that the effective momentum flow for the bottom quark forward–backward asymmetry should be other than the conventionally suggested . Moreover, the convergence of perturbative QCD series for is greatly improved using the PMC. Our prediction for the bare bottom quark forward–backward asymmetry is refined to be , which diminishes the well known tension between the experimental determination for this (pseudo) observable and the respective Standard Model fit to .