A search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

TL;DR

This paper reports a search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states using 13 TeV proton-proton collision data from the ATLAS detector, setting limits on production cross-sections and couplings.

Contribution

It introduces a search strategy for heavy Higgs bosons in same-sign dilepton channels and interprets results within an effective field theory framework, extending previous mass and coupling constraints.

Findings

No significant excess over Standard Model background observed.

Excluded heavy Higgs boson masses up to 900 GeV for certain couplings.

Set upper limits on production cross-section and coupling strengths.

Abstract

A search for heavy Higgs bosons produced in association with a vector boson and decaying into a pair of vector bosons is performed in final states with two leptons (electrons or muons) of the same electric charge, missing transverse momentum and jets. 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 observed data are in agreement with Standard Model background expectations. The results are interpreted using higher-dimensional operators in an effective field theory. Upper limits on the production cross-section are calculated at 95% confidence level as a function of the heavy Higgs boson's mass and coupling strengths to vector bosons. Limits are set in the Higgs boson mass range from 300 to 1500 GeV, and depend on the assumed couplings. The highest excluded mass for a heavy Higgs boson with the coupling combinations explored is 900 GeV. Limits on coupling strengths are also provided.