Speaker
Description
The Weinberg model is a Z_2\times Z_2-symmetric
three-Higgs-doublet model (3HDM)} designed to accommodate CP violation in the
scalar sector within a gauge theory, while at the same time allowing for natural
flavour conservation. In this model the coefficients of the potential are taken to be
complex and therefore CP is explicitly violated. With coefficients chosen to be real,
CP can be spontaneously violated via complex vacuum expectation values (vevs).
In the absence of the terms leading to the possibility of CP-violation either explicit
or induced by complex vevs, the potential has two U(1) symmetries. In this case,
spontaneous symmetry breaking would in general give rise to massless states. In a
realistic implementation, those terms must be included, thus preventing the
existence of Goldstone bosons. A scan over parameters, imposing the existence of
a neutral state at 125 GeV that is nearly CP-even, typically results in the existence
of one or two states with masses below 125 GeV that have a significant CP-odd
component. These light states would have a low production rate via the Bjorken
process and could thus have escaped detection at LEP.
