Brief comment on electro-weak breaking in superstring inspired model

Abstract

We reconsider Kalyniak and Sundaresan's (KS's) criticism about the models obtained by Breit et al. totally from a more phenomenological point of view. We study which fields inN _f (27) must acquire the vacuum expectation value (vev) rather than ones in$\delta (27 + \overline {27} )$ in order to break down toSU(3) _c ×U(1)_em symmetry without any extraU(1) at weak scale and endow quarks and leptons with masses. General sets of fields to acquire the vev are obtained. Further utilizing maximally the light components of$\delta (27 + \overline {27} )$, minimal sets of fields inN _f (27) to acquire the vev is listed up in each case of Breit et al. Also applying the conditions given there to more general cases, we find that there is only model free from KS's criticism.