Leptonic top quark asymmetry predictions at LHCb

The forward LHCb acceptance offers the possibility of measuring the top-quark pair asymmetry in a kinematic region that does not receive overwhelming dilution from the symmetric gluon-fusion channel. To investigate this possibility, two leptonic final states are identified, and analysis strategies are proposed for each channel with 14 TeV data. Leading fixed-order predictions are then provided for the relevant leptonic asymmetry variables in each channel. If backgrounds can be experimentally constrained, statistically, a nonzero asymmetry is estimated to be observable beyond $5\sigma$ confidence level with the full LHCb 14 TeV data.

Figure 1

Stacked contributions from signal and background processes to the symmetric cross section in the single-lepton channel at 14 TeV. Analysis cuts and relevant efficiencies have been applied to all processes. See text for details.

Figure 2

Differential leptonic rate asymmetry as a function of lepton pseudorapidity at 14 TeV. The choice of analysis cuts, and PDFs used for the computation of the numerator and denominator are highlighted.

Figure 3

Stacked signal and background contributions to the numerator of the total leptonic rate asymmetry at 14 TeV.

Figure 4

Stacked contributions from signal and background processes to the symmetric cross section in the dilepton channel at 14 TeV. Analysis cuts and relevant efficiencies have been applied to all processes. See text for details.