Could the Higgs mass be very light (< 1ev)?

[johne1618]

Has a very light (less than 1eV) Higgs mass been excluded by theory and/or experiment?

[CompuChip]

Yes. Masses up to at least some 90 GeV have been excluded by existing experiments, see for example HIGGS BOSONS: THEORY AND SEARCHES; Bernardi, Carena, Junk (http://pdg.lbl.gov/2010/reviews/rpp2010-rev-higgs-boson.pdf).

[fermi]

Has a very light (less than 1eV) Higgs mass been excluded by theory and/or experiment?

An extremely light Higgs (less than < 1ev) would be a catastrophe in astrophysics. Top amongst many other problems, it would destabilize stars like our own Sun.