Doubly-charged Higgs searches by ATLAS

A search for new physics in dilepton final states with same electric charge, $e^{\pm}e^{\pm}$, $e^{\pm}\mu^{\pm}$ and $\mu^{\pm}\mu^{\pm}$, with the ATLAS detector at LHC, is presented. No significant contribution from beyond the Standard Model physics is observed in 4.7$~$fb$^{-1}$ of $\sqrt{s}= 7~$TeV proton-proton collisions. An upper limit at 95% Confidence Level$~$(CL) on the fiducial cross section for new physics processes is derived, ranging between 1.7$~$fb and 64$~$fb depending on the dilepton invariant mass and the lepton flavour combination. A 95% CL limit is also set on the cross section for pair production of doubly-charged Higgs as a function of its mass, varying between 25$~$fb and 0.6$~$fb. Lower limits on the mass of doubly-charged Higgs bosons in the Left-Right symmetric models and in the Zee-Babu models are obtained.