Strong Double Higgs Production at the LHC

TL;DR

This paper investigates the potential for observing enhanced double Higgs production at the LHC, which could signal new physics beyond the Standard Model involving a pseudo-Goldstone Higgs.

Contribution

It analyzes the double Higgs production via vector boson fusion in a strongly-coupled scenario, highlighting the energy growth of scattering amplitudes as a key signature.

Findings

3 sigma significance for double Higgs detection with 300 fb^{-1} at 14 TeV

Enhanced double Higgs production rate compared to Standard Model

Complementary signals from same-sign lepton final states

Abstract

The hierarchy problem and the electroweak data, together, provide a plausible motivation for considering a light Higgs emerging as a pseudo-Goldstone boson from a strongly-coupled sector. In that scenario, the rates for Higgs production and decay differ significantly from those in the Standard Model. However, one genuine strong coupling signature is the growth with energy of the scattering amplitudes among the Goldstone bosons, the longitudinally polarized vector bosons as well as the Higgs boson itself. The rate for double Higgs production in vector boson fusion is thus enhanced with respect to its negligible rate in the SM. We study that reaction in pp collisions, where the production of two Higgs bosons at high pT is associated with the emission of two forward jets. We concentrate on the decay mode hh -> WW^(*)WW^(*) and study the semi-leptonic decay chains of the W's with 2, 3 or 4 leptons in the final states. While the 3 lepton final states are the most relevant and can lead to a 3 sigma signal significance with 300 fb^{-1} collected at a 14 TeV LHC, the two same-sign lepton final states provide complementary information. We also comment on the prospects for improving the detectability of double Higgs production at the foreseen LHC energy and luminosity upgrades.