One-loop flavor change in Little Higgs models

The Little Higgs (LH) idea attempts to cure the little amount of fine-tuning necessary to bridge the gap between the Higgs mass (electroweak scale) and the new physics scale suggested by electroweak precision tests (~10 TeV). However, we show that LH models do not survive the confrontation with experimental limits on lepton flavor mixing, assuming the same naturalness arguments that motivate their introduction. Two different LH models are analyzed and several aspects of their one-loop predictions for lepton flavor-changing processes are discussed.