Top and bottom quark forward-backward asymmetries at next-to-next-to-leading order QCD in (un)polarized electron positron collisions

• Published in: The journal of high energy physics Vol. 2023; no. 5; pp. 94 - 23
• Main Authors: Bernreuther, Werner, Chen, Long, Lu, Peng-Cheng, Si, Zong-Guo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 11.05.2023; Springer Nature B.V; SpringerOpen
• Subjects: Algorithms; Asymmetry; Bottom Quarks; Classical and Quantum Gravitation; Clustering; Electron beams; Electroweak Precision Physics; Elementary Particles; Flavor (particle physics); High energy physics; Higher-Order Perturbative Calculations; Pair production; Physics; Physics and Astronomy; Positron beams; Quantum chromodynamics; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Quarks; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Top Quark; Electroweak Precision Physics; Bottom Quarks; Top Quark; Higher-Order Perturbative Calculations
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2023)094

A bstract We consider, at order α s 2 in the QCD coupling, top-quark pair production in the continuum at various center-of-mass energies and b -quark pair production at the Z resonance by (un)polarized electron and positron beams. For top quarks we compute the forward-backward asymmetry with respect to the top-quark direction of flight, the associated polar angle distribution, and we analyze the effect of beam polarization on the QCD corrections to the leading-order asymmetry. We calculate also the polarized forward-backward asymmetry. For b -quark production at the Z peak we explore different definitions of A FB . In particular, we analyze b jets defined by the Durham and the flavor- k T clustering algorithms. We compute the inclusive b -jet and two-jet asymmetry with respect to the b -jet direction. For the latter asymmetry the QCD corrections to order α s 2 are small. That predestines it to act as a precision observable.