Searches for Long-Lived Decays of the Higgs Boson to Muons at ATLAS

Following the discovery of the Higgs boson at the LHC in 2012, the increase in available data has allowed the focus of Higgs research to transition from basic properties of the Higgs such as its mass and spin, to measurements requiring greater statistics such as couplings of known and new particles to the Higgs, and the branching ratios of its decays. With current LHC data, there is still significant room within the total Higgs cross section for decays beyond the Standard Model [1]. Exotic Higgs boson decays are therefore a promising avenue in which to look for new physics. There could exist new particles which couple to no Standard Model particles except the Higgs, meaning the Higgs acts as a window to a “dark sector” of physics which is otherwise inaccessible. Models of this type, called “Higgs portal” models, have the potential to address several open questions in physics, most notably through a potential Higgs coupling to dark matter.