Anomalous Wtb coupling at the LHC

TL;DR

This paper investigates how anomalous Wtb couplings affect muon distributions in top quark pair production at the LHC, finding moderate changes and minimal background interference.

Contribution

It provides leading order calculations of muon distributions considering dimension-five operators for anomalous Wtb couplings, highlighting their subtle effects.

Findings

Distributions in muon kinematic variables are only moderately affected by anomalous couplings.

Full Feynman diagram calculations yield similar results to simplified t anti-t diagrams.

Off resonance background contributions have negligible impact on the distributions.

Abstract

Some distributions of the mu- in the top quark pair production reaction pp -> b u anti-d anti-b mu- anti-nu_mu at the LHC are calculated to leading order in the presence of the anomalous Wtb coupling with operators of dimension up to five. The distributions in the transverse momentum, rapidity and cosine of the mu- angle with respect to the beam in the laboratory frame and with respect to the reversed momentum of the b-quark in the rest frame of W-boson are changed rather moderately by the anomalous Wtb coupling. The distributions computed with the full set of leading order Feynman diagrams practically do not differ from those computed with the t anti-t production diagrams, with typical acceptance cuts. This demonstrates very little effect of the off resonance background contributions.