The forward-backward asymmetry for massive bottom quarks at the $Z$ peak at next-to-next-to-leading order QCD

Abstract

We compute the order ${\alpha }_s^2$ QCD corrections to the $b$-quark forward-backward asymmetry in $e^{+}{e}^{-}\to b\bar{b}$ collisions at the $Z$ boson resonance, taking the non-zero mass of the $b$ quark into account. We determine these corrections with respect to both the $b$-quark axis and the thrust axis definition of the asymmetry. We compute also the distributions of these axes with respect to the electron beam. If one neglects the flavor singlet contributions to the $b$-quark asymmetry, as was done in previous computations for massless $b$ quarks, then the second-order QCD corrections for $m_b\ne 0$ are smaller in magnitude than the corresponding corrections for $m_b=0$. Including the singlet contributions slightly increases the magnitude of the corrections. The massive ${\alpha }_s^2$ corrections to the $b$-quark forward-backward asymmetry slightly diminish the well-known tension between the bare $b$-quark asymmetry and the standard model fit from $2.9\sigma$ to $2.6\sigma$.

arXiv commentLatex, 19 pages

References in corpus (15)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• ZFITTER v.6.21 - A Semi-Analytical Program for Fermion Pair Production in e+e- Annihilation
• Infrared safe definition of jet flavour
• Two-loop QCD Corrections to the Heavy Quark Form Factors: the Vector Contributions
• Resolving the Tevatron Top Quark Forward-Backward Asymmetry Puzzle: Fully Differential Next-to-Next-to-Leading-Order Calculation
• Physics Impact of GigaZ
• Two-Loop QCD Corrections to the Heavy Quark Form Factors: Anomaly Contributions
• Two-Loop QCD Corrections to the Heavy Quark Form Factors: Axial Vector Contributions
• Top-quark forward-backward asymmetry in e+e- annihilation at NNLO in QCD
• Corrections of Order α_s^2 to the Forward-Backward Asymmetry
• Second order QCD corrections to the forward-backward asymmetry in e^+e^- - collisions
• The forward-backward asymmetry at NNLO revisited
• Two-Parton Contribution to the Heavy-Quark Forward-Backward Asymmetry in NNLO QCD
• A Note on the QCD Corrections to Forward--Backward Asymmetries of Heavy--Quark Jets in Z Decays

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