Multi-Higgs production in gluon fusion at 100 TeV

TL;DR

This paper analyzes multi-Higgs production via gluon fusion at future 100 TeV colliders, revealing exponential growth in cross-sections with high multiplicities and energy, potentially challenging perturbative calculations.

Contribution

It provides a detailed calculation of high-multiplicity Higgs production, highlighting the factorial growth of diagrams and the energy scales where perturbativity breaks down.

Findings

Cross-sections grow exponentially with Higgs multiplicity.

Perturbative rates become significant around 100 TeV for ~130 Higgses.

At 50 TeV, cross-sections for 140 bosons reach picobarn levels.

Abstract

We carry out a detailed study of multi-Higgs production processes in the gluon fusion channel in the high energy regime relevant to Future Circular hadron colliders and in the high-Higgs-multiplicity limit (> 20). Our results are based on the computation of the leading polygons - the triangles, boxes, pentagons and hexagons - to the scattering processes, further combined with the subsequent branchings to reach high final state multiplicities. The factorial growth of the number of diagrams leads to an exponential enhancement of such large multiplicity cross-sections and, ultimately, in breaking of perturbativity. We find that the characteristic energy and multiplicity scales where these perturbative rates become highly enhanced and grow with increasing energy are within the 100 TeV regime with of the order of 130 Higgses (or more) in the final state. We also show that already for a 50 TeV hadron collider the perturbative cross-sections for 140 bosons are at picobarn level.