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Single top quark tW+X production at the LHC: a closer look

A. Belyaev, E. Boos

TL;DR

The paper reexamines tW+X single top production at the LHC, focusing on correct treatment of the 2→2 Wt process and the 2→3 Wtb corrections through a gauge-invariant subtraction of tt̄ contributions. It analyzes two subtraction schemes (invariant-mass cut vs narrow-width) and demonstrates the need to avoid double counting from collinear gluon splitting, proposing a consistent framework to combine Wt and Wtb across the full kinematic region. The study finds a total tW+X cross section near 62 pb at a top-mass-scale QCD choice and argues that accurate event simulation requires proper subtraction to reproduce correct kinematics. Overall, the work improves the modeling of the tW+X final state for top-quark property measurements and background estimation at the LHC.

Abstract

We have reexamined the tW+X single top-quark production process which is important at the LHC contrary to the Tevatron. The special attention was paid to the treatment of the 2->2[Wt] process and the part of it's next-to-leading correction: 2->3[Wtb] process. We show that 2->3[Wtb] process has to be correctly taken into account with a proper subtraction of the top pair contribution and that it has qualitatively different kinematical distributions from the 2->2[Wt] process. We present the total cross section of the tW+X production to be about 62 pb at QCD scale be taken as a top quark mass, suggest the method of combining Wt and Wtb processes with gauge invariant subtraction of the tt-bar part which allows to reproduce correct kinematical properties and perform a proper event simulation of the tW+X process in the whole kinematical region.

Single top quark tW+X production at the LHC: a closer look

TL;DR

The paper reexamines tW+X single top production at the LHC, focusing on correct treatment of the 2→2 Wt process and the 2→3 Wtb corrections through a gauge-invariant subtraction of tt̄ contributions. It analyzes two subtraction schemes (invariant-mass cut vs narrow-width) and demonstrates the need to avoid double counting from collinear gluon splitting, proposing a consistent framework to combine Wt and Wtb across the full kinematic region. The study finds a total tW+X cross section near 62 pb at a top-mass-scale QCD choice and argues that accurate event simulation requires proper subtraction to reproduce correct kinematics. Overall, the work improves the modeling of the tW+X final state for top-quark property measurements and background estimation at the LHC.

Abstract

We have reexamined the tW+X single top-quark production process which is important at the LHC contrary to the Tevatron. The special attention was paid to the treatment of the 2->2[Wt] process and the part of it's next-to-leading correction: 2->3[Wtb] process. We show that 2->3[Wtb] process has to be correctly taken into account with a proper subtraction of the top pair contribution and that it has qualitatively different kinematical distributions from the 2->2[Wt] process. We present the total cross section of the tW+X production to be about 62 pb at QCD scale be taken as a top quark mass, suggest the method of combining Wt and Wtb processes with gauge invariant subtraction of the tt-bar part which allows to reproduce correct kinematical properties and perform a proper event simulation of the tW+X process in the whole kinematical region.

Paper Structure

This paper contains 2 sections, 2 equations, 2 figures.

Table of Contents

  1. Introduction
  2. Leading order $2\to 2$ and $\cal O$($1/log m_t^2/m_b^2$) $2\to 3$ process: subtraction of $t\bar{t}$ pair production

Figures (2)

  • Figure 1: Diagrams for leading order $2\to 2$$tW$ production (A) and $\cal O$($1/log m_t^2/m_b^2$) $2\to 3$ process (B), (C)
  • Figure :