ABSTRACT

The ATLAS experiment, the world’s largest particle detector at the Large Hadron Collider (LHC) at CERN, is designed to probe the fundamental structure of matter and the forces that govern the Universe. Since its groundbreaking discovery of the Higgs boson, ATLAS has continued to deliver precise measurements of the Higgs boson’s properties and wide-ranging searches for new physics beyond the Standard Model. In recognition of its scientific contributions, the ATLAS collaboration was awarded the 2025 Breakthrough Prize in Fundamental Physics.

In this seminar, I will present recent highlights from ATLAS in the most precise studies of the Higgs boson to date and investigations into the origin of the matter–antimatter asymmetry in the Universe in the Higgs sector. Special emphasis will be placed on Higgs boson decays to tau leptons, a channel where the Hong Kong ATLAS team has played a leading role. I will also discuss the exciting prospects for ATLAS in addressing some of the most profound open questions in particle physics and cosmology during the next phases of the LHC program.

BIOGRAPHY

Ki Lie is a Research Assistant Professor in the Department of Physics at the Hong Kong University of Science and Technology (HKUST), specializing in experimental particle physics. He earned his Ph.D. from the University of Illinois at Urbana-Champaign before joining the HKUST Jockey Club Institute for Advanced Study (IAS) as an IAS Postdoctoral Fellow. He became a Research Assistant Professor in the Department of Physics at HKUST in 2022.

Lie is a member of the Center for Fundamental Physics at the IAS at HKUST and plays a key role in the Hong Kong ATLAS team, operated under the Joint Consortium of Fundamental Physics in Hong Kong, a collaborative initiative among CUHK, HKU, and HKUST.