To be honest I am rather skeptical that a fundamental Standard Model Higgs boson will exist. Even before the Tevatron started producing exclusion limits, the searches from an older collider called LEP said it must have a mass of more than 114 GeV (1 GeV is approximately the proton mass). On the other hand, a variety of precision data about the Standard Model said the best fit would be at about 90 GeV, which was already excluded by LEP. This does not rule out the Higgs, but does make it slightly surprising.
Since then, the Tevatron have produced results on limits to the Higgs production rate, such as this plot here: . To interpret that plot you want to concentrate on the black “V” shaped line – that is the predicted Standard model production rate for a Higgs, and any time it is above the horizontal line at 1 it means they should have seen a Higgs if it were there. So the only mass range left is between perhaps about 150-180. The yellow and green bands say what happens if the production rate is a little bit different, so you might say it could be between 140-190-ish GeV.
In addition to that, the Higgs mechanism has some theoretical issues caused by the hierarchy problem (the large difference in strength between gravity and all of the other forces).
So I don’t think it looks good for the Higgs boson, but it is not ruled out yet. If I were a betting man I would have my money on it not existing. We will only know for sure in a couple of years when the LHC has taken enough data.
If I were a betting man, I would propose a bet to James 🙂
I think a Higgs boson exists and will be found at the LHC. It is very hard to explain the properties of weak nuclear forces without a particle that would have the characteristics of the Higgs boson. This is the case even if the standard model of particle physics wasn’t exactly correct.