Di-Higgs phenomenology: The forgotten channel

TL;DR

This paper investigates the potential of the $pp\to t\bar t hh$ process at LHC run 2 to improve constraints on the Higgs trilinear coupling, focusing on challenging multi-Higgs final states.

Contribution

It introduces the study of the $pp\to t\bar t hh$ channel as a new observable for Higgs physics at the LHC, expanding beyond the commonly analyzed $gg\to hh+jets$ process.

Findings

$pp\to t\bar t hh$ can help constrain the Higgs trilinear coupling.

The channel is promising with $h\to b\bar b$ and top decays.

Potential to improve global Higgs coupling fits.

Abstract

Searches for multi-Higgs final states allow to constrain parameters of the SM (or extensions thereof) that directly relate to the mechanism of electroweak symmetry breaking. Multi-Higgs production cross sections, however, are small and the phenomenologically accessible final states are challenging to isolate in the busy multi-jet hadron collider environment of the LHC run 2. This makes the necessity to extend the list of potentially observable production mechanisms obvious. Most of the phenomenological analyses in the past have focused on $gg\to hh+jets$; in this paper we study $pp\to t\bar t hh$ at LHC run 2 and find that this channel for $h\to b\bar b$ and semi-leptonic and hadronic top decays has the potential to provide an additional handle to constrain the Higgs trilinear coupling in a global fit at the end of run 2.