Multi-Lepton Events at H1 and Search for Doubly-Charged Higgs Bosons

Events with two or more leptons (electrons or muons) with high transverse momentum are measured in electron-proton collisions at HERA using the data sample collected in the period 1994-2005. Multi-lepton events at high transverse momenta are of special interest as these signature might reveal new physics beyond the Standard Model. An example is the single production of doublycharged Higgs bosons HLplus/minus plus/minus L,R, which couple to leptons of the i'th and j th generation via Yukawa couplings hL,Rij. Results from a search for doubly-charged Higgs bosons in the decays into electrons, muons and taus are presented using data taken in the period 1994-2000. No evidence for doublycharged Higgs production is found and we derive limits on the h LRee and hLRem Yukawa couplings as a function of the HLplus/minus plus/minus LR mass.