Several beyond the standard model theories suggest that the 125 GeV Higgs boson discovered at the LHC may be part of a larger symmetry. The two-Higgs doublet model extended with a complex scalar singlet (2HDM+S) is of particular interest since it provides a wide range of possible Higgs decays. As a result of small mixing with the Higgs doublets, the singlet state produces a physical pseudoscalar (a) that can decay into SM particles. The ATLAS and CMS experiments have explored many searches under the 2HDM+S framework, considering different possible decays and covering a mass range from 0.3 to 65 GeV. This presentation will discuss the most sensitive H->aa searches with final states involving b quarks, taus, and muons. Past results and present efforts for studying other channels will be briefly presented, along with their prospects for Run 3.
Pallabi Das earned her PhD in 2019 from the Tata Institute of Fundamental Research, Mumbai, India, and joined Princeton University, USA as a postdoctoral research associate. Her main research interest has been the SM Higgs boson, and through its properties identifying potential new physics signatures. During her PhD, she worked on measuring anomalous top Yukawa couplings in the single top associated production of the Higgs boson. More recently, she has been involved in the search for exotic Higgs decays to pairs of pseudoscalars, which then decay to SM particles. She also dedicates a substantial effort to measure and improve the performance of the CMS trigger system.
Yesenia Hernandez Jimenez did her Ph.D. at the Instituto de Física Corpuscular (Valencia, Spain) and during this period she was directly involved in the search for the Standard Model (SM) Higgs boson in the H->WW->lvlv channel with the ATLAS detector. In 2016, she started in a postdoctoral researcher position at the University of Wits (Johannesburg, South Africa) and she was involved in the associated production of the SM Higgs particle with a Z boson. During this position, she was also involved in the search for boson pair production in the WWWW decay channel. In 2019, she was appointed to be the analysis contact of the HH-Multilepton group in ATLAS. Since February 2021, she works at the Stony Brook University (New York, USA) as a postdoctoral researcher where she has developed a strong interest in searching for exotic decays of the SM Higgs boson. Currently, Yesenia is a convener of the Higgs and Light Resonant Searches sub-group in ATLAS. On the detector side, she is involved in the LAr calorimeter of ATLAS, developing detector operation and data preparation activities.