Phenomenology of tt¯j + X production at the LHC

A bstract We present phenomenological results for t t ¯ j + X production at the Large Hadron Collider, of interest for designing forthcoming experimental analyses of this process. We focus on those cases where the t t ¯ j + X process is considered as a signal. We discuss present theoretical uncertainties and the dependence on relevant input parameters entering the computation. For the R distribution, which depends on the invariant mass of the t t ¯ j -system, we present reference predictions in the on-shell, MS ¯ and MSR top-quark mass renormalization schemes, applying the latter scheme to this process for the first time. Our conclusions are particularly interesting for those analyses aiming at extracting the top-quark mass from cross-section measurements.