Hayrapetyan, A.Tumasyan, A.Adam, W.Andrejkovic, J.W.Bergauer, T.Chatterjee, S.Damanakis, K.Gürpınar Güler, EmineGüler, Yalçın2024-06-192024-06-1920241434-60441434-6052https://doi.org/10.1140/epjc/s10052-024-12727-4https://hdl.handle.net/20.500.13091/5736A search for exotic decays of the Higgs boson (H) with a mass of 125GeV to a pair of light pseudoscalars a1 is performed in final states where one pseudoscalar decays to two b quarks and the other to a pair of muons or τ leptons. A data sample of proton–proton collisions at s=13TeV corresponding to an integrated luminosity of 138fb-1 recorded with the CMS detector is analyzed. No statistically significant excess is observed over the standard model backgrounds. Upper limits are set at 95% confidence level (CL) on the Higgs boson branching fraction to μμbb and to ττbb, via a pair of a1s. The limits depend on the pseudoscalar mass ma1 and are observed to be in the range (0.17–3.3) ×10-4 and (1.7–7.7) ×10-2 in the μμbb and ττbb final states, respectively. In the framework of models with two Higgs doublets and a complex scalar singlet (2HDM+S), the results of the two final states are combined to determine upper limits on the branching fraction B(H→a1a1→ℓℓbb) at 95% CL, with ℓ being a muon or a τ lepton. For different types of 2HDM+S, upper bounds on the branching fraction B(H→a1a1) are extracted from the combination of the two channels. In most of the Type II 2HDM+S parameter space, B(H→a1a1) values above 0.23 are excluded at 95% CL for ma1 values between 15 and 60GeV. © The Author(s) 2024.eninfo:eu-repo/semantics/openAccessBosonsCharged particlesTellurium compoundsVanadium compoundsBranching fractionsConfidence levelsData sampleExotic decayFinal stateHiggs bosonIntegrated luminosityProton proton collisionsPseudoscalarsUpper limitsScattering parametersArticle10.1140/epjc/s10052-024-12727-42-s2.0-85193357686