Speaker
Description
Exotic Higgs decays are among the most promising areas to be explored at the High Luminosity Large Hadron Collider, given the unprecedentedly large amount of the Standard Model-like Higgs bosons that will be produced. In this context, we introduce a new search channel where a Higgs boson with a mass of 125 GeV decays to a Z boson and a light pseudoscalar (a), in the final state with two muons and two $\tau$ leptons ($ h\to Z a\to \mu\mu\tau\tau $). In the preliminary analysis, performed at a center-of-mass energy of $\sqrt{s}=$13 TeV, masses of the pseudoscalar boson between 3.5 and 30 GeV are probed, focusing on the kinematic region where the $ h\to Z a$ decay is on-shell. We analyze several collider variables to propose a suitable signal region and consider the different decay channels for the di-tau system, as sensitivity is strongly influenced by the $\tau\tau$ reconstruction efficiency. Model-independent limits are set at the 95$\%$ confidence level as a function of $m_a$. Upper limits are also established within the Axion-Like Particle (ALP) framework, based on a specific model motivated by the anomalous $g-2$ measurement.
