Speaker
Description
This work extends previous ATLAS Run-2 analyses to improve the search for new physics through the decay of a beyond-Standard-Model Higgs boson, 𝐻→𝑍𝐴. The theoretical framework is the Two-Higgs-Doublet Model, in which the Higgs sector is extended by an additional scalar doublet. The particle 𝐴 is a light (0.5–3.0 GeV) CP-odd scalar predicted in minimal extensions of the Standard Model and expected to decay hadronically. The experimental signature involves a dilepton pair from the 𝑍- boson and a highly collimated jet from the boosted 𝐴. A feasibility study is ongoing using Monte Carlo simulations and neural-network techniques, comparing previous ATLAS results and new simulated samples. Improved selection methods and analysis strategies are being developed to enhance the sensitivity to the 𝐻→𝑍𝐴 signal and its significance over background, aiming for optimised performance with the upcoming Run-3 dataset.
