Aad, G.Aakvaag, E.Abbott, B.Abdelhameed, S.Abeling, K.Abicht, N.J.Abidi, S.H.Aboelela, M.Aboulhorma, A.Abramowicz, H.Abreu, H.Abulaiti, Y.Acharya, B.S.Ackermann, A.Adam Bourdarios, C.Adamczyk, L.Addepalli, S.V.Addison, M.J.Adelman, J.Adiguzel, A.et al.2025-05-082025-05-082024Journal of High Energy Physics (JHEP), 2024; 2024(12):126-0-126-501029-84791029-8479https://hdl.handle.net/2440/144434Published: December 17, 2024This paper reports a search for a light CP-odd scalar resonance with a mass of 20 GeV to 90 GeV in 13TeV proton-proton collision data with an integrated luminosity of 140 fb−1 collected with the ATLAS detector at the Large Hadron Collider. The analysis assumes the resonance is produced via gluon-gluon fusion and decays into a τ⁺τ⁻ pair which subsequently decays into a fully leptonic μ⁺νμ¯ντ e−¯νeντ or e⁺νe¯ντμ−¯νμντ final state. No significant excess of events above the predicted Standard Model background is observed. The results are interpreted within a flavour-aligned two-Higgs-doublet model, and a modelindependent cross-section interpretation is also given. Upper limits at 95% confidence level between 3.0 pb and 68 pb are set on the cross-section for producing a CP-odd Higgs boson that decays into a τ⁺τ⁻ pair.enOpen Access, Copyright CERN, for the benefit of the ATLAS Collaboration. Article funded by SCOAP3. Open Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.Hadron-Hadron Scattering; Higgs PhysicsJournal article10.1007/jhep12(2024)126726859Fewell, M.P. [0000-0002-4406-0430]Jackson, P. [0000-0002-0847-402X]McDougall, A.E. [0000-0001-7713-2800]Potti, H. [0000-0002-0800-9902]Ting, E.X.L. [0000-0002-5886-6339]White, M.J. [0000-0001-5474-4580]