ATLAS searches for additional scalars and exotic Higgs boson decays with the LHC Run 2 dataset

Abstract

This report reviews the published results of searches for possible additional scalar particles and exotic decays of the Higgs boson performed by the ATLAS Collaborationusing up to 140 fb-1 of 13 TeV proton-proton collision data collected during Run 2of the Large Hadron Collider. Key results are examined, and observed excesses, whilenever statistically compelling, are noted. Constraints are placed on parameters of severalmodels which extend the Standard Model, for example by adding one or more singletor doublet fields, or offering exotic Higgs boson decay channels. Summaries of newsearches as well as extensions of previous searches are discussed. These new resultshave a wider reach or attain stronger exclusion limits. New experimental techniquesthat were developed for these searches are highlighted. Search channels which have notyet been examined are also listed, as these provide insight into possible future areas ofexploration.