A search for exotic decays of the Higgs boson (H) with a mass of 125 GeV 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 sqrt(s) = 13 TeV corresponding to an integrated luminosity of 138 fb-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 m_a1 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 m_a1 values between 15 and 60 GeV.
Search for exotic decays of the Higgs boson to a pair of pseudoscalars in the mu mu bb and tau tau bb final states
Cappati, A.;Meridiani, P.;Amapane, N.;Argiro, S.;Bellan, R.;Bellora, A.;Costa, M.;Covarelli, R.;Grippo, M.;Kiani, B.;Luongo, F.;Mecca, A.;Migliore, E.;Mulargia, R.;Obertino, M. M.;Pacher, L.;Siviero, F.;Sola, V.;Solano, A.;Soldi, D.;Tarricone, C.;Tornago, M.;Umoret, G.;Shchelina, K.;Rumerio, P.;Ravera, F.;Salvatico, R.;Vagnerini, A.;
2024-01-01
Abstract
A search for exotic decays of the Higgs boson (H) with a mass of 125 GeV 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 sqrt(s) = 13 TeV corresponding to an integrated luminosity of 138 fb-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 m_a1 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 m_a1 values between 15 and 60 GeV.| File | Dimensione | Formato | |
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