Hidden sector effects on double higgs production near threshold at the LHC

TL;DR

This paper explores how a hidden sector coupled to the Higgs boson can significantly enhance double Higgs production near threshold at the LHC, potentially revealing new physics beyond the Standard Model.

Contribution

It introduces a novel effect of hidden sector coupling causing large enhancements in double Higgs production cross section near threshold, with detailed calculations relating to the effective ggHH coupling.

Findings

Enhancement of the order of 100 in partonic cross section near threshold.

LHC cross section could be up to 10 times larger than the Standard Model.

Potential to gain insights into the hidden sector through collider experiments.

Abstract

In this letter we study a novel effect of a hidden sector coupling to the standard model Higgs boson: an enhancement of the Higgs pair production cross section near threshold due to bound state effects. After summing the ladder contributions of the hidden sector to the effective $ggHH$ coupling, we find the amplitude for gluon-gluon scattering via a Higgs loop. We relate this amplitude to the double Higgs production cross section via the optical theorem. We find that enhancements of the order of 100 for the partonic cross section near the threshold region can be obtained for a hidden sector strongly coupled to the Higgs boson. The corresponding cross section at the LHC can be as large as a factor of 10 times the SM result for extreme values of the coupling. The detection of such an effect could in principle lead to important information about the hidden sector.