Search for a New Scalar Decaying Into New Spin-1 Bosons in Four-Lepton Final States With the ATLAS Detector

Abstract

A search is conducted for a new scalar boson S, with a mass distinct from that of the Higgs boson, decaying promptly into four leptons (l = e, mu) via an intermediate state containing two on-shell, promptly decaying new spin-1 bosons Z(d): S -> Z(d)Z(d) -> 4l, where the Z(d) boson has a mass between 15 and 300 GeV, and the S boson has a mass between either 30 and 115 GeV or 130 and 800 GeV. The search uses proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider with an integrated luminosity of 139 fb(-1) at a centre-of-mass energy of root s = 13 TeV. No significant excess above the Standard Model background expectation is observed. Upper limits at 95% confidence level are set on the production cross-section times branching ratio, sigma(gg -> S) x B(S -> Z(d)Z(d) -> 4l), as a function of the mass of both particles, m(S) and m(Zd).