New Physics in LHC Higgs boson pair production

TL;DR

The paper addresses how LHC di-Higgs production can illuminate the realization of electroweak symmetry breaking beyond the Standard Model. It systematically analyzes resonant and nonresonant new physics scenarios affecting di-Higgs and di-Higgs+jet channels, including Higgs portal and MSSM at low tanβ, as well as pseudo-Nambu-Goldstone frameworks with a pseudo-dilaton or composite Higgs. It provides quantitative predictions for cross sections and invariant-mass distributions, and discusses boosted strategies that enhance sensitivity to trilinear couplings and new resonances. The work concludes that combined dihiggs and dihiggs+jet measurements, especially at high luminosity, can reconstruct portal parameters, constrain MSSM mixing angles, and discriminate between composite and dilatonic EWSB realizations.

Abstract

Multi-Higgs production provides a phenomenologically clear window to the electroweak symmetry breaking sector. We perform a comprehensive and comparative analysis of new electroweak physics effects in di-Higgs and di-Higgs+jet production. In particular, we discuss resonant di-Higgs phenomenology, which arises in the Higgs portal model and in the MSSM at small tan beta, and non-resonant new physics contributions to di-Higgs production in models where the newly discovered Higgs candidate is interpreted as a pseudo-Nambu-Goldstone boson. We show that, for all these scenarios, a measurement of the di-Higgs and di-Higgs+jet final states provides an accessible and elaborate handle to understand electroweak symmetry breaking in great detail.

Figures (10)

• Figure 1: Mass of the heavy Higgs state $H$ if $m_{h}=125~{\rm{GeV}}$, and consistency with $S,T,U$Peskin:1991sw, unitarity and current ATLAS/CMS results is imposed. The density of the model points must not be interpreted as a probability measure.
• Figure 2: Upper panels: cross sections in the portal scenario for the parameter point mentioned in the text. We scan over the multiples of the trilinear couplings Eq. (\ref{['eq:tricouplings']}) that are in one-to-one correspondence with diagrams involving the $h,H$ propagators and show contours relative to the central expectation Eq. (\ref{['eq:portalres']}). Lower panels: invariant di-Higgs mass distributions.
• Figure 3: Invariant mass distribution for $pp\to hh+j+X$ in the portal scenario.
• Figure 4: Invariant mass distribution of the (a) $hh$ and the (b) $Hh$ system for MSSM-like production at low $tan\beta$. For details see text.
• Figure 5: Dilaton production from gluon fusion with current limits of the $h\gamma \gamma$ coupling analysis plehnino included.