  This letter presents the results of a search for a heavy particle decaying
into an e mu, e tau, or mu tau final state in pp collisions at sqrt(s) = 7 TeV.
The data were recorded with the ATLAS detector at the LHC during 2011 and
correspond to an integrated luminosity of 4.6/fb. No significant excess above
the Standard Model expectation is observed, and exclusions at 95% confidence
level are placed on the cross section times branching ratio for the production
of an R-parity-violating supersymmetric tau sneutrino. These results
considerably extend constraints from Tevatron experiments.
