Irreducible background and interference effects for Higgs-boson production in association with a top-quark pair

TL;DR

This paper analyzes Higgs production with top quarks at the LHC, focusing on irreducible backgrounds and interference effects, revealing significant background contributions and the importance of including non-resonant and interference effects for accurate predictions.

Contribution

It provides a detailed comparison of resonant and full process scenarios, highlighting the impact of non-resonant and interference effects on Higgs-top production predictions.

Findings

Irreducible background is three times the signal with standard cuts.

A uniform 8% deviation between resonant and full process scenarios.

Neglecting interference overestimates cross-section by 5%.

Abstract

We present an analysis of Higgs-boson production in association with a top-quark pair at the LHC investigating in particular the final state consisting of four b jets, two jets, one identified charged lepton and missing energy. We consider the Standard Model prediction in three scenarios, the resonant Higgs-boson plus top-quark-pair production, the resonant production of a top-quark pair in association with a b-jet pair and the full process including all non-resonant and interference contributions. By comparing these scenarios we examine the irreducible background for the production rate and several kinematical distributions. With standard selection criteria the irreducible background turns out to be three times as large as the signal. For most observables we find a uniform deviation of eight percent between the scenario requiring two resonant top quarks and the full process. In particular phase-space regions the non-resonant contributions cause larger effects, and we observe shape changes for some distributions. Furthermore we investigate interference effects and find that neglecting interference contributions results in an over-estimate of the total cross-section of five percent.