Vector-like quarks in a "composite" Higgs model

Abstract

Vector-like quarks are a common feature of ''composite'' Higgs models, where they intervene in cutting off the top-loop contribution to the Higgs boson mass and may, at the same time, affect the Electroweak Precision Tests (EWPT). A model based on SO(5)/SO(4) is here analyzed. In a specific non minimal version, vector-like quarks of mass as low as 300-500 GeV are allowed in a thin region of its parameter space. Other models fail to be consistent with the EWPT. © 2008 SISSA.