Multilepton production via top flavour-changing neutral couplings at the CERN LHC

TL;DR

This paper investigates the potential of multilepton production processes at the CERN LHC to constrain top quark flavour-changing neutral couplings, highlighting the sensitivity of Zt and gamma t production channels.

Contribution

It provides a detailed analysis of Zt and gamma t production modes to set bounds on top flavour-changing neutral couplings, comparing their effectiveness to top decay measurements.

Findings

Bounds on tc couplings are comparable to top decay limits.

Limits on tu couplings are improved by a factor of two.

Other Z and W decay modes are also analyzed.

Abstract

Zt and gamma t production with Z -> l+ l- and t -> Wb -> l nu b provides the best determination of top flavour-changing neutral couplings at the LHC. The bounds on tc couplings eventually derived from these processes are similar to those expected from top decays, while the limits on tu couplings are better by a factor of two. The other significant Z and W decay modes are also investigated.