Search for doubly and singly charged Higgs bosons decaying into vector bosons in multi-lepton final states with the ATLAS detector using proton-proton collisions at 13 TeV

This poster presents a search for charged Higgs bosons decaying into 𝑊+-𝑊+- or 𝑊+-𝑍 bosons, involving experimental signatures with two leptons of the same charge, or three or four leptons with a variety of charge combinations, missing transverse momentum and jets. Some focus will be given on the same-charge leptons channel signature in which I have been closely involved. A data sample of proton–proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb−1. The search is guided by a type-II seesaw model that extends the scalar sector of the Standard Model with a scalar triplet, leading to a phenomenology that includes doubly and singly charged Higgs bosons. Two scenarios are explored, corresponding to the pair production of doubly charged 𝐻++/-- bosons, or the associated production of a doubly charged 𝐻++/-- boson and a singly charged 𝐻+/- boson. No significant deviations from the Standard Model predictions are observed. 𝐻++/-- bosons are excluded at 95% confidence level up to 350 GeV and 230 GeV for the pair and associated production modes, respectively.