Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 21: BSM Higgs 1 (extended Higgs sectors)
T 21.2: Talk
Monday, March 4, 2024, 16:15–16:30, Geb. 30.41: HS 3
Search for a light CP-odd Higgs boson with the ATLAS detector — •Manuel Gutsche, Asma Hadef, Hannah Jacobi, Tom Kreße, Christian Schmidt, and Arno Straessner — Technische Universität Dresden
While the Standard Model of particle physics (SM) has proven to be a precisely predictive theory, tensions between experimental observations and theoretical calculations have arisen. One such discrepancy originates from Fermilab’s measurement of the muon’s anomalous magnetic moment aµ. The flavour-aligned two-Higgs-doublet model (2HDM) is an extension of the SM that introduces a second Higgs doublet, leading to a rich phenomenology with four additional Higgs bosons. One of these particles is the CP-odd and electrically neutral A-boson whose mass mA is a free parameter of the theory. If A is assumed to have a low mass of less than mZ and large couplings to leptons as well as top quarks, the 2HDM could explain the observed deviation in aµ.
In this talk, the search for an A-boson with a mass between 20 GeV and 110 GeV, produced by gluon fusion and decaying into two τ leptons, is presented. The analysis focuses on the channel with one electron and one muon in the final state, making use of 140.1 fb−1 of data recorded by the ATLAS detector at √s = 13 TeV.
An overview of the analysis strategy is given. Different validation and signal-enriched regions along with the employed fake estimation method are introduced. Details on the most impactful systematic uncertainties as well as the expected limits for the production cross-section and model-dependent coupling parameters are presented.
Keywords: tau leptons; two-Higgs-doublet model; anomalous magnetic moment of the muon; physics beyond the Standard Model