  A search for heavy Majorana neutrinos in events containing a pair of
high-$p_{\mathrm{T}}$ leptons of the same charge and high-$p_{\mathrm{T}}$ jets
is presented. The search uses $20.3 \mathrm{fb}^{-1}$ of $pp$ collision data
collected with the ATLAS detector at the CERN Large Hadron Collider with a
centre-of-mass energy of $\sqrt{s} = 8$ TeV. The data are found to be
consistent with the background-only hypothesis based on the Standard Model
expectation. In the context of a Type-I seesaw mechanism, limits are set on the
production cross-section times branching ratio for production of heavy Majorana
neutrinos in the mass range between 100 and 500 GeV. The limits are
subsequently interpreted as limits on the mixing between the heavy Majorana
neutrinos and the Standard Model neutrinos. In the context of a left-right
symmetric model, limits on the production cross-section times branching ratio
are set with respect to the masses of heavy Majorana neutrinos and heavy gauge
bosons $W_{\mathrm{R}}$ and $Z'$.

High Energy Physics - Experiment