Yy. Liu et al., CHIRAL EXTENSION OF THE STANDARD MODEL, Nuovo cimento della Società Italiana di Fisica. A. Nuclei, particles and fields, 108(2), 1995, pp. 167-174
The chiral extension of the minimal standard model makes quarks with t
wo chiralities present parallely. Some interesting questions, such as
the possibility that leptons are made of additional leptonic quarks an
d the proton decay are discussed.