New physics in t-> b W decay at next-to-leading order in QCD

Abstract

We consider contributions of non-standard tbW effective operators to the decay of an unpolarized top quark into a bottom quark and a W gauge boson at next-to-leading order in QCD. We find that the dipole operator O_{LR} contribution to the transverse-plus W helicity fraction F_+ is significantly enhanced compared to the leading order result at non-vanishing bottom quark mass. Nonetheless, presently the most sensitive observable to direct O_{LR} contributions is the longitudinal W helicity fraction F_L. In particular, the most recent CDF measurement of F_L already provides the most stringent upper bound on O_{LR} contributions, even when compared with indirect bounds from the rare decay B -> X_s gamma.

5 pages

References in corpus (3)

• Probing anomalous Wtb couplings in top pair decays
• ATLAS sensitivity to Wtb anomalous couplings in top quark decays
• QCD Corrections to Flavor Changing Neutral Coupling Mediated Rare Top Quark Decays

Cited by in corpus (7)

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• A survey of top quark polarization at a polarized linear e^+ e^- collider
• Effective approach to top-quark decay and FCNC processes at NLO accuracy
• Scalar production and decay to top quarks including interference effects at NLO in QCD in an EFT approach
• $O({\alpha }_s)$ perturbative and nonperturbative corrections to polarized semileptonic ${\Lambda }_b$ decay distributions