Accurate predictions for charged Higgs production: closing the $m_{H^{\pm}}\sim m_t$ window

TL;DR

This paper provides the first next-to-leading order (NLO) predictions for charged Higgs boson production in the intermediate-mass range at the LHC, significantly improving accuracy and reducing uncertainties compared to previous lowest-order estimates.

Contribution

It introduces the first NLO calculation for charged Higgs production at intermediate masses, bridging the gap between low- and high-mass regimes in the two-Higgs-doublet model.

Findings

NLO corrections increase the cross section by about 50%

Scale uncertainties are reduced by more than a factor of two

Results interpolate reliably between low- and high-mass regimes

Abstract

We present predictions for the total cross section for the production of a charged Higgs boson in the intermediate-mass range ($m_{H^{\pm}}\sim m_t$) at the LHC, focusing on a type-II two-Higgs-doublet model. Results are obtained at next-to-leading order (NLO) accuracy in QCD perturbation theory, by studying the full process $pp\to H^\pm W^\mp b \bar b$ in the complex-(top)-mass scheme with massive bottom quarks. Compared to lowest-order predictions, NLO corrections have a sizeable impact: they increase the cross section by roughly 50\% and reduce uncertainties due to scale variations by more than a factor of two. Our computation reliably interpolates between the low- and high-mass regime. Our results provide the first NLO prediction for charged Higgs production in the intermediate-mass range and therefore allow to have NLO accurate predictions in the full $m_{H^{\pm}}$ range. The extension of our results to different realisations of the two-Higgs-doublet model or to the supersymmetric case is also discussed.