Phenomenology of on-shell Higgs production in the MSSM with complex parameters

TL;DR

This paper provides detailed calculations of Higgs boson production cross sections in the MSSM with complex parameters, including higher-order QCD and electroweak corrections, and discusses the impact of complex phases on squark effects.

Contribution

It introduces an advanced computational framework for Higgs production in the MSSM with complex parameters, incorporating higher-order corrections and phase effects, implemented in the SusHiMi code.

Findings

Squark effects depend strongly on the phases of complex parameters.

Theoretical uncertainties for cross sections are discussed.

Results are integrated into the SusHiMi code for practical use.

Abstract

A computation of inclusive cross sections for neutral Higgs boson production through gluon fusion and bottom-quark annihilation is presented in the MSSM with complex parameters. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for arbitrary complex parameters which is supplemented by higher-order corrections: massive top- and bottom-quark contributions at NLO QCD, in the heavy top-quark effective theory the top-quark contribution up to N$^3$LO QCD including a soft expansion for the $\mathcal{CP}$-even component of the light Higgs boson. For its $\mathcal{CP}$-odd component and the heavy Higgs bosons the contributions are incorporated up to NNLO QCD. Two-loop electroweak effects are also incorporated, and SUSY QCD corrections at NLO are interpolated from the MSSM with real parameters. Finite wave function normalisation factors ensuring correct on-shell properties of the external Higgs bosons are incorporated from the code $\texttt{FeynHiggs}$. For the typical case of a strong admixture of the two heavy Higgs bosons it is demonstrated that squark effects are strongly dependent on the phases of the complex parameters. The remaining theoretical uncertainties for cross sections are discussed. The results have been implemented into an extension of the numerical code $\texttt{SusHi}$ called $\texttt{SusHiMi}$.