Boosted and Resolved Jet Assignment using Symmetry-Preserving Attention Networks in Nonresonant Multi-Higgs-Boson Events

The Higgs boson’s self-coupling has a significant impact on the production rate of multiple Higgs bosons. Measuring the self-coupling at the CERN LHC is crucial because any deviations from our expectations could potentially lead to new discoveries of physics beyond the standard model of particle physics. Most events are fully hadronic, meaning every Higgs boson decays to a bottom quark-antiquark pair. This introduces a combinatorial challenge known as the jet assignment problem, in which jets are assigned to Higgs boson candidates. For a given event topology, symmetry-preserving attention networks (SPA-Nets) have been introduced to address this challenge. However, the complexity of this challenge increases when considering different reconstruction topologies for each Higgs boson candidate simultaneously, i.e., two “resolved'' small-radius jets each containing a cascade initiated by a bottom quark or one “boosted'' large-radius jet containing a merged cascade initiated by a bottom quark-antiquark pair. In this work, we generalize the SPA-Net approach to simultaneously consider both boosted and resolved reconstruction possibilities and unambiguously interpret an event as “fully resolved,'' “fully boosted,'' or in between. We report the performance of baseline methods, the original SPA-Net approach, and our generalized version on nonresonant HH and HHH production simulated by Pythia and Delphes.