New physics at future linear electron-positron colliders

Future high energy linear electron positron colliders with centre-of-mass energies between 500 and 1000 GeV offer a unique opportunity to precisely study phenomena from new physics processes. Most important, the mechanism of electroweak symmetry breaking can be established in full depth if one or more Higgs bosons are observed. If supersymmetric particles are found within the kinematical reach of the machine, their properties can be studied with high precision allowing to obtain information about the breaking mechanism of supersymmetry and thus about energy scales far above the available centre-of-mass energy. Alternative scenarios including large extra space dimensions, leptoquarks and lepton flavour violation decays can also be studied. (author)