Constraints on the quartic Higgs self-coupling from double-Higgs production at future hadron colliders

TL;DR

This paper investigates how future high-energy proton colliders can indirectly constrain the quartic Higgs self-coupling through calculations of two-loop contributions to double-Higgs production, enhancing understanding of Higgs potential.

Contribution

It provides the first two-loop calculations involving a modified $h^4$ vertex for double-Higgs production, estimating collider sensitivities to Higgs self-couplings.

Findings

Future colliders at 27 TeV and 100 TeV can significantly constrain Higgs self-couplings.

Two-loop contributions are crucial for accurate indirect constraints.

Measurements of double- and triple-Higgs production are key to probing the Higgs potential.

Abstract

We study the indirect constraints on the quartic Higgs self-coupling that arise from double-Higgs production at future hadron colliders. To this purpose, we calculate the two-loop contributions to the $gg \to hh$ amplitudes that involve a modified $h^4$ vertex. Based on our results, we estimate the reach of a $pp$ collider operating at $27 \, {\rm TeV}$ and $100 \, {\rm TeV}$ centre-of-mass energy in constraining the cubic and quartic Higgs self-couplings by measurements of double-Higgs and triple-Higgs production in gluon-fusion.