Single top quarktW+Xproduction at the CERN LHC: A closer look

We reexamine the $tW+X$ single top-quark production process, which is important at the CERN LHC, unlike what happens at the Fermilab Tevatron. Special attention is paid to the treatment of the $\overrightarrow{2}2\left[\mathrm{Wt}\right]$ process and part of its next-to-leading correction, the $\overrightarrow{2}3\left[\mathrm{Wtb}\right]$ process. We show that the $\overrightarrow{2}3\left[\mathrm{Wtb}\right]$ 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 $\overrightarrow{2}2\left[\mathrm{Wt}\right]$ process. We present the total cross section of the $tW+X$ production as being about 62 pb, and at the proper QCD scale equal to the top quark mass, suggest a method of combining the $\mathrm{Wt}$ and $\mathrm{Wtb}$ processes with gauge-invariant subtraction of the $t\overline{t}$ part, which allows us to reproduce the kinematical properties correctly and perform a proper event simulation of the $tW+X$ process in the whole kinematical region.