Anomaly Free Gauged $SU(4)_L\times U(1)_X$ Models with Little Higgs

Abstract

We present an analysis showing how anomaly free fermionic spectra with consistent embeddings of the Standard Model spectrum under $SU(3)_C\times SU(2)_L\times U(1)_Y \subset SU(3)_C\times SU(N)_L\times U(1)_X$ for any $N>2$ can be obtained, with special focus on the $N=3 {and} 4$ cases. The construction is motivated by the little Higgs mechanism. We discuss the relevancy of the fermionic spectra to the latter, concentrating on two N=4 models, without fermions of exotic charges. Such models hold the promise to address and solve all the major theoretical as well as phenomenological problems of the Standard Model at the TeV scale.