  An inclusive search is presented for new physics in events with two isolated
leptons (electron or muon) having the same electric charge. The data are
selected from events collected from pp collisions at sqrt(s) = 7 TeV by the
ATLAS detector and correspond to an integrated luminosity of 34 inverse
picobarns. The spectra in dilepton invariant mass, missing transverse momentum
and jet multiplicity are presented and compared to Standard Model predictions.
In this event sample, no evidence is found for contributions beyond those of
the Standard Model. Limits are set on the cross-section in a fiducial region
for new sources of same-sign high-mass dilepton events in the di-electron,
di-muon and electron-muon channels. Four models predicting same-sign dilepton
signals are constrained: two descriptions of Majorana neutrinos, a cascade
topology similar to supersymmetry or universal extra dimensions, and fourth
generation down-type quarks. Assuming a new physics scale of 1 TeV, Majorana
neutrinos produced by an effective operator V with masses below 460 GeV are
excluded at 95% confidence level. A lower limit of 290 GeV is set at 95%
confidence level on the mass of fourth generation down type quarks.
