Göttingen 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

T: Fachverband Teilchenphysik

T 25: Higgs Physics IV (BSM Higgs)

T 25.3: Vortrag

Dienstag, 1. April 2025, 16:45–17:00, ZHG105

Search for a light CP-odd Higgs boson decaying into a pair of τ-leptons in proton–proton collisions at √s=13 TeV with the ATLAS detector — •Manuel Gutsche, Asma Hadef, Tom Kreße, Christian Schmidt, and Arno Straessner — Technische Universität Dresden

The two-Higgs-doublet model (2HDM) continues to be one of the most well-motivated extensions of the Standard Model. The theory postulates a second Higgs doublet, thus predicting the existence of in total five Higgs bosons h, H, H^±, A, of which the latter A boson is electrically neutral and CP-odd. A certain choice of the model’s parameters leads to the flavour-aligned 2HDM, which is able to explain discrepancies in the anomalous magnetic moment of the muon for an A boson mass of less than m_Z as well as large couplings to leptons and up-type quarks.

This talk presents a search for a CP-odd Higgs boson which is produced via gluon fusion and decays into two τ-leptons in the mass range of 20 GeV to 90 GeV. For this, the analysis uses 140 fb⁻¹ of data recorded by the ATLAS detector at √s = 13 TeV, focusing on the leptonic decays of the τ-leptons to exactly one electron and one muon.

After explaining the analysis strategy and event selection, an overview of fake-lepton estimation and most impactful systematic uncertainties is given. The expected and observed exclusion limits for the model-independent production cross-section, as well as for the coupling parameter to up-type quarks interpreted in the flavour-aligned 2HDM, are presented.

Keywords: tau lepton; Higgs boson; two-Higgs-Doublet-Model; fake lepton estimation; anomalous magnetic moment of the muon