Search for Decays of the Higgs Boson Into a Pair of Pseudoscalar Particles Decaying Into <i>b</I>(<i>b< Using <i>pp</I> Collisions at √<i>s</I>=13 Tev With the Atlas Detector

Abstract

This paper presents a search for exotic decays of the Higgs boson into a pair of new pseudoscalar particles, H -> aa, where one pseudoscalar decays into a b-quark pair and the other decays into a tau-lepton pair, in the mass range 12 <= m(a) <= 60 GeV. The analysis uses pp collision data at root s = 13 TeV collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 140 fb(-1). No significant excess above the Standard Model ( SM) prediction is observed. Assuming the SM Higgs boson production cross section, the search sets upper limits at 95% confidence level on the branching ratio of Higgs bosons decaying into b (b) over bar tau(+)tau(-), B(H -> aa -> b (b) over bar tau(+)tau(-)), between 2.2% and 3.9% depending on the pseudoscalar mass.