Top-Quark Decay at Next-to-Next-to-Leading Order in QCD

Abstract

We present the complete calculation of the top-quark decay width at next-to-next-to-leading order in QCD, including next-to-leading electroweak corrections as well as finite bottom quark mass and W boson width effects. In particular, we also show the first results of the fully differential decay rates for the top-quark semileptonic decay t → W(+)(l(+)ν)b at next-to-next-to-leading order in QCD. Our method is based on the understanding of the invariant mass distribution of the final-state jet in the singular limit from effective field theory. Our result can be used to study arbitrary infrared-safe observables of top-quark decay with the highest perturbative accuracy.

Electroweak production of top-quark pairs ine+e−annihilation at NNLO in QCD: The vector current contributions

“…For instance, top quark decay [99], Drell-Yan production [140], and Higgs production [141] have all been studied in schemes very similar to the one described in this work. This paper demonstrates that phase-space slicing can also be used to calculate top quark production processes, albeit at e + e − colliders.…”

NNLO QCD predictions for fully-differential top-quark pair production at the Tevatron

“…Although NNLO theoretical predictions for distributions of top-quark decay products are preferred, such a calculation is beyond the scope of the present work given the significant additional effort its implementation would require (despite the fact that differential NNLO top decay is known [13,14]). We are planning to undertake such a calculation in the future.…”

A complete basis of helicity operators for subleading factorization

“…Subtraction schemes based on factorization theorems include the recently introduced N -jettiness subtraction scheme [137][138][139], based on the N -jettiness event shape [140], as well as the SCET based subtraction scheme for NNLO semileptonic top quark decays of ref. [141]. Subleading factorization theorems would allow for the subtraction of the next-to-singular terms, potentially improving the numerical accuracy and speed of the techniques.…”