Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 2. $t$-channel Process

TL;DR

This work delivers a comprehensive NLO QCD analysis of t-channel single top production at the Tevatron, including production and decay with spin preserved via a modified narrow width approximation. It quantifies inclusive cross sections, scale and mass dependencies, and decomposes radiative corrections into LIGHT, HEAVY, and TDEC contributions, finding a modest total rate increase (~5%) but notable effects on event topology and jet multiplicities. The study systematically evaluates acceptance under realistic cuts, explores final-state distributions, and presents robust top-quark polarization measurements across helicity, spectator, and beamline bases, even after reconstruction. It also analyzes three-jet final states to disentangle production- and decay-stage radiation, providing practical guidance for experimental analyses and spin-phenomenology in t-channel single top events.

Abstract

We present a study of the $t$-channel mode of single top quark production at the upgraded Tevatron $p\bar{p}$ collider, including the next-to-leading order (NLO) QCD corrections to the production and the decay of a single top quark. The narrow width approximation was adopted in order to preserve the spin of the top quark in its production and decay. We discuss the effects of different $O(α_s)$ contributions on the inclusive cross section as well as various kinematic distributions after imposing the relevant cuts to select $t$-channel single top signal events.

Figures (26)

• Figure 1: The theoretical cutoff $s_{min}$ dependence of the inclusive $t$-channel single top quark cross section at the Tevatron with $\mu_{R}=\mu_{F}=m_{t}$ for $m_{t}=178\,{\rm GeV}$. The decay branching ratio $t\rightarrow bW^{+}(\rightarrow e^{+}\nu)$ has been included.
• Figure 2: Top quark mass dependence as well as renormalization and factorization scale dependence of the inclusive $t$-channel single top quark cross section at the Tevatron. The decay branching ratio of $t\to bW^{+}(\to e^{+}\nu)$ has been included.
• Figure 3: Inclusive $t$-channel single top quark production cross section at the Tevatron for $m_{t}=178$ GeV, versus the ratio of the factorization scale $\mu_{F}$ to its typical value $\mu_{0}$, where $\mu_{0}=m_{t}$ (solid line) and $\mu_{0}=M_{W}$ (dashed line), respectively. The decay branching ratio of $t\to bW^{+}(\to e^{+}\nu)$ has been included.
• Figure 4: Pictorial illustration of the notation used in this paper.
• Figure 5: Representative diagrams of the real emission corrections for the $t$-channel single top process: (a) and (b) represent the real radiative corrections to the LIGHT quark line, while (c) and (d) represent the real radiative corrections to the HEAVY quark line. The NLO QCD corrections are indicated by the large shaded ellipse. Detailed Feynman diagrams can be found in Ref. Cao:2004ky.