Top Partners and Higgs Boson Production

TL;DR

This paper investigates how heavy vector-like fermions can alter Higgs boson production rates at the LHC, comparing exact calculations, low energy theorem, and effective theory to identify potential enhancements in double Higgs production.

Contribution

It provides a detailed comparison of production rate calculations for Higgs pairs, highlighting the accuracy of effective theory over low energy theorem in the presence of heavy fermions.

Findings

EFT accurately describes double Higgs kinematic distributions.

Heavy vector-like fermions can enhance double Higgs production.

EFT outperforms LET in modeling heavy fermion effects.

Abstract

The Higgs boson is produced at the LHC through gluon fusion at roughly the Standard Model rate. New colored fermions, which can contribute to $gg\rightarrow h$, must have vector-like interactions in order not to be in conflict with the experimentally measured rate. We examine the size of the corrections to single and double Higgs production from heavy vector-like fermions in $SU(2)_L$ singlets and doublets and search for regions of parameter space where double Higgs production is enhanced relative to the Standard Model prediction. We compare production rates and distributions for double Higgs production from gluon fusion using an exact calculation, the low energy theorem (LET), where the top quark and the heavy vector-like fermions are taken to be infinitely massive, and an effective theory (EFT) where top mass effects are included exactly and the effects of the heavy fermions are included to ${\cal O}(1/M^2_X)$. Unlike the LET, the EFT gives an extremely accurate description of the kinematic distributions for double Higgs production.