Hadronic Higgs production through NLO+PS in the SM, the 2HDM and the MSSM

TL;DR

The paper introduces aMCSusHi, a workflow that couples SusHi amplitudes with MadGraph5_aMC@NLO to deliver NLO QCD predictions for gluon-fusion Higgs production across the SM, 2HDM, and MSSM with full mass dependence and MC@NLO-based parton-shower matching. It details script-based automation for setup, parameter interfacing via SLHA blocks, and a sophisticated shower-scale treatment to handle bottom-quark contributions. The authors demonstrate the method’s robustness across different parton showers and illustrate applications to bottom-d dominated 2HDM scenarios and MSSM pseudoscalars, achieving reliable predictions with reduced scale uncertainties. This tool enhances precision phenomenology for Higgs production in BSM theories and provides a practical path to integrate higher-order corrections with realistic event simulation. It will be valuable for collider phenomenology, model testing, and future refinements involving higher-multiplicity matching or resummation.

Abstract

The NLO cross section of the gluon fusion process is matched to parton showers in the MC@NLO approach. We work in the framework of MadGraph5_aMC@NLO and document the inclusion of the full quark-mass dependence in the SM as well as the state-of-the-art squark and gluino effects within the MSSM embodied in the program SusHi. The combination of the two programs is realized by a script which is publicly available and whose usage is detailed. We discuss the input cards and the relevant parameter switches. One of our focuses is on the shower scale which is specifically important for gluon-induced Higgs production, particularly in models with enhanced Higgs-bottom Yukawa coupling.

Figures (5)

• Figure 1: A sample of Feynman diagrams for $gg\rightarrow \phi$ contributing to the .9 NLO cross section; (a-c) .9 LO, (d-g) virtual and (h-i) real corrections. The graphical notation for the lines is: solid straight $\widehat{=}$ quark; spiraled $\widehat{=}$ gluon; dashed $\widehat{=}$ scalar (squark or Higgs); spiraled with line $\widehat{=}$ gluino.
• Figure 2: Transverse momentum distribution of a .9 SM Higgs at .9 NLO.9 +.9 PS in the full theory normalized to the one in the heavy top effective field theory for different Monte Carlos: Pythia8 (black solid), Herwig++ (red, dotted), Pythia6$p_T{}$-ordered (blue, dashed with points), Pythia6$Q$-ordered (green, dash-dotted with open boxes) and Herwig6 (yellow, solid with filled boxes).
• Figure 3: (a) Same as Fig. \ref{['fig:me']}, but for different choices of the shower scales, see text for details; (b) corresponding plot for the rapidity distribution of the Higgs.
• Figure 4: Transverse momentum distribution of (a) the heavy Higgs boson and (b) the associated hardest jet computed in a bottom dominated scenario of the .9 2HDM (see text for details). Graphical notation is the following: black solid curve shows Pythia8 at .9 NLO.9 +.9 PS, red dotted curve is the same at .9 LO.9 +.9 PS (normalized the .9 NLO) and the blue dashed one with points corresponds to the fixed order curve at .9 NLO.
• Figure 5: Rapidity distribution of (a) the pseudo-scalar Higgs boson and (b) the associated hardest jet computed in the $m_h^{\text{mod}+}$ scenario Carena:2013qia of the .9 MSSM with $M_A=800$ GeV und $\tan\beta=40$. Graphical notation is the same as in Fig. \ref{['fig:2HDM']}. All curves are normalized so that their bins add up to one.