In a series of approximatley 30 papers starting in 1991, it has been claimed that the Higgs field should be heavier than its now-measured value. To reconcile this idea with reality, it was modified to the assertion that the Higgs field describes two physical degrees of freedom, one of which corresponds to a second Higgs particle with mass 690 GeV. Here the lack of theoretical and experimental evidence for these claims is summarized.
James M. Cline (Fri,) studied this question.