Deconstructing resonant Higgs pair production at the LHC: effects of coloured and neutral scalars in the NMSSM test case

TL;DR

This paper investigates how new neutral and coloured scalars in the NMSSM can affect resonant Higgs pair production at the LHC, revealing interference effects that can distort signals and provide insights into new physics.

Contribution

It demonstrates the sensitivity of the LHC to interference effects involving resonant and non-resonant diagrams in Higgs pair production within the NMSSM, using amplitude decomposition and benchmark scenarios.

Findings

Interference effects can significantly distort Higgs resonance signals.

Certain benchmark points show observable features in multiple decay channels.

Analysis enables detailed interpretation of new physics contributions.

Abstract

We study resonant production of pairs of Standard Model (SM)-like Higgs bosons, in the presence of new neutral Higgs states together with new coloured scalars (stops or sbottoms) in loops within the Next-to-Minimal Supersymmetric SM (NMSSM). This is used as a test case to prove that the Large Hadron Collider has sensitivity to a variety of effects stemming from interferences between resonant (heavy) Higgs diagrams and/or among these and non-resonant topologies involving loops of both tops and stops. These effects can alter significantly the naive description of individual $s$-channel Breit-Wigner resonances, leading to distortions of the latter which, on the one hand, may mask their presence but, on the other hand, could enable one to extract features of the underlying new physics scenario. This last aspect is made possible through a decomposition of the $gg\to hh$ signal process into all its amplitude components, each of which has a well-defined coupling structure. Ultimately, such effects can be traced back to the relevant Feynman diagrams and can enable a detailed interpretation of this process. To illustrate this, we introduce various Benchmark Points that exhibit potentially observable features during the current and/or upcoming runs of the LHC in one or more of the three customary di-Higgs decay channels: $b\bar bb\bar b$, $b\bar b \tau^+\tau^-$ and $b\bar b\gamma\gamma$.