Higgs Pair Production at Future Hadron Colliders: From Kinematics to Dynamics

TL;DR

This paper explores how future high-energy colliders can precisely measure the Higgs self-coupling through Higgs pair production, utilizing invariant mass distributions and simulations to estimate potential sensitivities.

Contribution

It introduces a systematic method using invariant mass distributions to extract the Higgs self-coupling at future colliders, with realistic simulations and energy upgrade scenarios.

Findings

High-energy LHC upgrade to 27 TeV can achieve 5σ observation with 2.5 ab$^{-1}$.

Potential to measure Higgs self-coupling with 15-30% accuracy at 68-95% CL at 27 TeV.

A 100 TeV collider could measure the self-coupling with better than 5-10% accuracy.

Abstract

The measurement of the triple Higgs coupling is a key benchmark for the LHC and future colliders. It directly probes the Higgs potential and its fundamental properties in connection to new physics beyond the Standard Model. There exist two phase space regions with an enhanced sensitivity to the Higgs self-coupling, the Higgs pair production threshold and an intermediate top pair threshold. We show how the invariant mass distribution of the Higgs pair offers a systematic way to extract the Higgs self-coupling, focusing on the leading channel $pp\to hh+X\to b\bar b\ \gamma\gamma+X$. We utilize new features of the signal events at higher energies and estimate the potential of a high-energy upgrade of the LHC and a future hadron collider with realistic simulations. We find that the high-energy upgrade of the LHC to 27 TeV would reach a 5$\sigma$ observation with an integrated luminosity of 2.5 ab$^{-1}$. It would have the potential to reach 15% (30%) accuracy at the 68% (95%) confidence level to determine the SM Higgs boson self-coupling. A future 100 TeV collider could improve the self-coupling measurement to better than 5% (10%) at the 68% (95%) confidence level.