Scalar and pseudoscalar Higgs production in association with a top–antitop pair

R Frederix,S Frixione,V Hirschi,F Maltoni,R Pittau,P Torrielli

doi:10.1016/j.physletb.2011.06.012

Abstract

We present the calculation of scalar and pseudoscalar Higgs production in association with a top–antitop pair to the next-to-leading order (NLO) accuracy in QCD, interfaced with parton showers according to the MC@NLO formalism. We apply our results to the cases of light and very light Higgs boson production at the LHC, giving results for total rates as well as for sample differential distributions, relevant to the Higgs, to the top quarks, and to their decay products. This work constitutes the first phenomenological application of aMC@NLO, a fully automated approach to complete event generation at NLO in QCD.

Highlights

Establishing evidence for the Higgs boson(s), i.e., the scalar remnant(s) of the Englert-Brout-Higgs mechanism [1, 2, 3] in the standard model and in extensions thereof, is among the most challenging goals of the LHC experiments
As prescribed by the MC@next-to-leading order (NLO) formalism, the showering and hadronisation steps are performed by the event generator the NLO computation is matched to, i.e. Herwig in this Letter
Accurate and flexible predictions for Higgs physics will play an important role in understanding the nature of the EWSB sector in the standard model and beyond

Summary

Introduction

Establishing evidence for the Higgs boson(s), i.e., the scalar remnant(s) of the Englert-Brout-Higgs mechanism [1, 2, 3] in the standard model and in extensions thereof, is among the most challenging goals of the LHC experiments. This matching procedure has been completely automated, and this work represents the first application of the MC@NLO technique to non-trivial processes which were previously available only at fixed order and at the parton level – in other words, to processes not already matched to showers by means of a dedicated, final-state-specific, software. AMC@NLO uses MadFKS for phase-space generation and for the computation of the pure-NLO short distance cross section of non-virtual origin, and on top of that it computes the MC subtraction terms.

Results

Conclusion