A supersymmetric SpL​(6)×UY​(1) model (SUSY Sp(6)) is proposed
as an extension of the standard electroweak model. The model is applied in a
phenomenological study of Bd0​Bˉd0​ mixing. It is found that
the supersymmetric (SUSY) partner z~′ of the extra
Z′ can significantly cancel the other contributions to bring the
mixing parameter xd​ within the experimentally allowed range 0.57∼<xd​∼<0.77 for a top mass of 158∼<mt​∼<194 Gev. Other interesting and
possibly novel features of flavor changing neutral currents (FCNC) in SUSY
theories with horizontal gauge symmetries are pointed out.Comment: to be published at the Il Nuovo Cimento A; uses FEYNMAN.tex; hard
copy available from G. G. Blado ([email protected]) by regular mail
upon e-mail request