  Many Standard Model extensions predict doubly-charged scalars; in particular,
all models with resonances in charged lepton-pair channels with non-vanishing
lepton number; if these are pair produced at the LHC, the observation of their
decay into $l^\pm l^\pm W^\mp W^\mp$ will be necessary in order to establish
their lepton-number violating character, which is generally not
straightforward. Nonetheless, the analysis of events containing four charged
leptons (including scalar decays into one or two taus as well as into W bosons)
makes it possible to determine whether the doubly-charged excitation belongs to
a multiplet with weak isospin T = 0, 1/2, 1, 3/2 or 2 (assuming there are no
excitations with charge > 2); though discriminating between the isosinglet and
isodoublet cases is possible only if charged-current events cannot produce the
doubly-charged isosinglet.
