$hhjj$ production at the LHC

TL;DR

This study analyzes di-Higgs production in association with two jets (hhjj) at the 14 TeV LHC, focusing on both GF and WBF production and their sensitivity to modifications of the Higgs self-interactions and Higgs–gauge couplings. It demonstrates the critical importance of including finite top-mass effects for GF hhjj, developing a reweighting framework to combine EFT generation with full-mass corrections and trilinear coupling variations. The work compares GF and WBF signatures, assesses dominant backgrounds, and proposes selection strategies to isolate each production mode and to constrain quartic VVhh couplings, including a projection of HL-LHC sensitivities. It concludes that hhjj can provide valuable, complementary information on the Higgs sector despite small rates, with event-shape observables offering additional discrimination avenues and potential MVAs to enhance sensitivity.

Abstract

The search for di-Higgs production at the LHC in order to set limits on Higgs trilinear coupling and constraints on new physics is one of the main motivations for the LHC high luminosity phase. Recent experimental analyses suggest that such analyses will only be successful if information from a range of channels is included. We therefore investigate di-Higgs production in association with two hadronic jets and give a detailed discussion of both the gluon- and weak boson fusion contributions, with a particular emphasis on the phenomenology with modified Higgs trilinear and quartic gauge couplings. We perform a detailed investigation of the full hadronic final state and find that $hhjj$ production should add sensitivity to a di-Higgs search combination at the HL-LHC with 3 ab$^{-1}$. Since the WBF and GF contributions are sensitive to different sources of physics beyond the Standard Model, we devise search strategies to disentangle and isolate these production modes. While gluon fusion remains non-negligible in WBF-type selections, sizeable new physics contributions to the latter can still be constrained. As an example of the latter point we investigate the sensitivity that can be obtained for a measurement of the quartic Higgs-gauge boson couplings.

Figures (9)

• Figure 1: Maximum Higgs and jet transverse momenta for gluon fusion-induced $hhjj$ production, including the ratio of full theory to the effective theory calculation for three different values of the Higgs trilinear coupling $\lambda$.
• Figure 2: Sample Feynman diagrams contributing to $pp\to hhjj$ via gluon fusion.
• Figure 3: Invariant mass and pseudo-rapidity distributions of the jet system in QCD-mediated $hhjj$ production. We show the effective theory and full theory results for three values of the trilinear Higgs coupling, applying only generator-level cuts of $p_{T,j} \ge 20$ GeV and $|\eta_j| < 5$.
• Figure 4: Invariant mass and pseudo-rapidity distributions of the leading jet and di-Higgs system in QCD-mediated $hhjj$ production. We show the effective theory and full theory results for three values of the trilinear Higgs coupling, applying only generator-level cuts of $p_{T,j} \ge 20$ GeV and $|\eta_j| < 5$.
• Figure 5: Sample Feynman diagrams contributing to $pp \to hhjj$ in weak boson fusion.