Discriminating Z' signals in semileptonic top pair production at the LHC

TL;DR

This paper explores how top pair production at the LHC can reveal properties of new neutral bosons predicted by Beyond the Standard Model theories, using detailed simulations and asymmetry observables.

Contribution

It introduces a comprehensive analysis including off-shell effects, interference, and realistic experimental conditions to discriminate Z' signals in semileptonic top pair events.

Findings

Asymmetry observables effectively probe the coupling structure of Z' bosons.

Asymmetries can complement differential cross sections for discovery.

Full simulation enhances the sensitivity to new physics signals.

Abstract

We investigate the sensitivity of top pair production to the properties of different Beyond the Standard Model theories embedding a new neutral boson. We include six-fermion decay, and account for the full tree-level Standard Model ttbar interference, with all intermediate particles allowed off-shell. We focus on those observables best suited to the lepton-plus-jets final state at the LHC, and simulate the resulting experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in quark-top assignment. In particular, we demonstrate the use of asymmetry observables to probe the coupling structure of a new neutral resonance, in addition to cases in which these asymmetries may even form complementary discovery observables in combination with the differential cross section.