Charged Higgs-boson production in association with an electron and a neutrino at electron-positron colliders

TL;DR

This paper provides the first complete one-loop calculations of charged Higgs boson production with an electron and neutrino at electron-positron colliders in the MSSM and THDM, highlighting model-dependent differences and validating approximation methods.

Contribution

It presents the first full one-loop computation of the process in both models, clarifying the validity of common approximation techniques and emphasizing the impact of superpartners in the MSSM.

Findings

MSSM includes pentagon-type Feynman graphs absent in THDM.

The process is loop-induced and highly model-dependent.

Validation of heavy fermion and sfermion loop approximations.

Abstract

We present results of a calculation of the cross section for the production of a charged Higgs boson in association with an electron and a neutrino at electron-positron colliders (e+ e- -> H+ e- nu_e-bar, H- e+ nu_e). We study predictions for the cross section in the Minimal Supersymmetric Standard Model (MSSM) and the Two Higgs Doublet Model (THDM), highlighting possible differences. The process is effectively loop-induced in both models. Hence, the cross section is expected to be strongly model-dependent. Most notably, due to the presence of superpartners, the MSSM amplitude contains Feynman graphs of pentagon-type, which are not present in the THDM. This is the first complete one-loop calculation of the cross section for this process in the THDM and the MSSM. For both models, so far, only approximate results with limited ranges of validity were available. Our main aim here is to clarify several open questions in the existing literature on this process. Specifically, we will discuss the validity of the Heavy Fermion loop approximation in both models, and of the Fermion/Sfermion loop approximation in the MSSM.