Search for doubly charged Higgs boson production in multi-lepton final states with the ATLAS detector using proton-proton collisions at $\sqrt{s}$ = 13 TeV (1710.09748v2)
Abstract: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton-proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 $\mathrm{fb}{-1}$ of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC. This analysis focuses on the decays $H{\pm\pm}\rightarrow e{\pm}e{\pm}$, $H{\pm\pm}\rightarrow e{\pm}\mu{\pm}$ and $H{\pm\pm}\rightarrow \mu{\pm}\mu{\pm}$, fitting the dilepton mass spectra in several exclusive signal regions. No significant evidence of a signal is observed and corresponding limits on the production cross-section are derived at 95% confidence level. The observed lower limit on the mass of a doubly charged Higgs boson only coupling to left-handed leptons ($e$,$\mu$) varies from 770 GeV to 870 GeV (850 GeV expected) for $B(H{\pm\pm}\rightarrow \ell{\pm}\ell{\pm})$ = 100% and both the expected and observed mass limits are above 450 GeV for $B(H{\pm\pm}\rightarrow \ell{\pm}\ell{\pm})$ = 10% and any combination of partial branching ratios.