QCD and Yukawa corrections to single-top-quark production via q qbar -> t bbar

TL;DR

Smith and Willenbrock compute the next-to-leading-order QCD and Yukawa corrections to the single-top production process $q\bar{q} \to t\bar{b}$, enabling precise extraction of $|V_{tb}|$ at the Tevatron and LHC. They treat initial- and final-state QCD corrections within a Drell-Yan–like, $W^*$-mediated framework, finding sizable but controllable cross-section increases and reduced scale dependence at NLO. The Yukawa corrections, arising from Higgs and scalar-vector loops, are shown to be negligible ($<1\%$) across a broad Higgs mass range in the SM. The paper provides final cross sections with quantified PDF, scale, and top-mass uncertainties, concluding that Run II should yield a few-percent precision on $|V_{tb}|$ and highlighting the process as a background to associated Higgs production.

Abstract

We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the production of a single top quark via the weak process q qbar -> t bbar at the Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation of the cross section is necessary in order to extract |V_tb| from experiment.

Figures (10)

• Figure 1: Single-top-quark production via $q \bar{q} \to t \bar{b}$.
• Figure 2: Single-top-quark production via $W$-gluon fusion.
• Figure 3: ${\sl O}(\alpha_s)$ correction to $q \bar{q} \to t \bar{b}$: (a)-(c) initial state, (d) final state.
• Figure 4: Factorization-scale dependence of the leading-order (LO) and next-to-leading-order (NLO) cross sections for $q\bar{q}\to t\bar{b}, \bar{t} b$ at the Tevatron and the LHC. The NLO cross sections include only the initial-state QCD correction, and not the final-state correction. The LO cross sections are calculated with the CTEQ3L LO parton distribution functions, and the NLO cross sections with the CTEQ3M NLO parton distribution functions.
• Figure 5: Renormalization-scale dependence of the leading-order (LO) and next-to-leading-order (NLO) cross sections for $q\bar{q}\to t\bar{b}, \bar{t} b$ at the Tevatron and the LHC. The NLO cross sections include both the initial-state and final-state correction. The LO cross sections are calculated with the CTEQ3L LO parton distribution functions, and the NLO cross sections with the CTEQ3M NLO parton distribution functions.