2006/04/04 by W. Bernreuther, R. Bonciani, Roberto Bonciani +7 · 2 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2006.05.031
published as Nucl.Phys.B750:83-107,2006 · latex, 26 pages, 2 tables, 17 figures
arxiv created 2006/04/04 · openalex publication_date 2006/06/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Forward-backward asymmetries, AFBQ, are important observables for the determination of the neutral-current couplings of heavy quarks in inclusive heavy quark production, e+ e- → γ^*, Z^* → Q +X. In view of the measurement perspectives on AFBQ at a future linear collider, precise predictions of AFBQ are required for massive quarks. We compute the contribution of the Q Q final state to AFBQ to order \as2 in the QCD coupling. We provide general formulae, and we show that this contribution to AFBQ is infrared-finite. We evaluate these two-parton contributions for b and c quarks on and near the Z resonance, and for t quarks above threshold. Moreover, near the t t threshold we obtain, by expanding in the heavy-quark velocity β, an expression for AFBt t to order \as2 and NNLL in β. This quantity is equal, to this order in β, to the complete forward-backward asymmetry AFBt.