Precise predictions for single-top production: the impact of EW corrections and QCD shower on the t-channel signature

Abstract

In this work we calculate and provide precise predictions for the signature that is typically exploited at the LHC for the measurement of t-channel single-top production: 1 lepton, 1 light jet, 1 b-jet, / E T and no additional jets or leptons. We apply the cuts that define the fiducial region and we take into account all the contributions to this signature; not only those from resonant t-channel single-top production. On the one hand, we calculate the complete-NLO corrections, i.e., all NLO effects of QCD and EW origin. On the other hand, we study in detail the impact of a QCD parton shower for the fiducial region we consider. We provide predictions in different approximations at the inclusive level and for several differential distributions. Our study demonstrates the relevance of both EW corrections and shower effects for obtaining precise and reliable theoretical predictions for the single-top-production fiducial region.

NLO QCD+EW predictions for tHj and tZj production at the LHC

“…For more details on this effect see appendix A in ref. [25]. For all distributions, the impact of NLO EW corrections remains within the scale uncertainty band of the NLO QCD results, approaching the lower edge of the band in the tails of the distributions.…”

“…The same effect has been observed for single top production in ref. [25] and found to be related to the tW h channel contribution, which enters only at NLO QCD accuracy and populates the central region of the η(j l,1 ) distributions. Indeed, when a light jet emerges from the W -boson decay, no enhancement is present in the region close to the beam-pipe axis, at variance with the light jet emerging from t-channel production.…”

“…Expanding in powers of α s and α and following the notation already used in refs. [17][18][19][20][21][22][23][24][25], the different contributions to any differential or inclusive cross section Σ can be denoted as:…”

“…First, performing a calculation for the signature itself, as it has been done in ref. [25] for the NLO QCD+EW corrections in t-channel single-top production or in refs. [30][31][32] for NLO QCD corrections in the tW associated production, where in both cases no additional associated Z or H boson production has been taken into account.…”

“…This would be equivalent to the calculation of ref [25]. with at least two additional particles in the final state.…”