Wait, what? New Higgs boson results? Did you think it was over? Oh hell no.
A post today from physicist Matt Strassler discussing the newest Higgs findings puts it well, “Knowledge about nature does not come easy.” We’ll be learning about the Higgs boson for decades. First off, there’s still all kinds of very basic questions to be answered about the particle. Like, well, what is it? At first, it looked to be something in the ballpark of the Standard Model Higgs boson, but not exactly what was predicted by our current dominant particle map. Some expected decay products were missing in the July results.
And is there more than one variety of Higgs particle? Not much is pointing to a solitary Higgs boson, but that could well change. This week’s data shows a slight inclination toward that idea.
So, happening right now is the Hadron Collider Physics Symposium in Kyoto, where the new results are being announced. Researchers at the LHC have roughly doubled the amount of data they have to analyze, and the main finding is that the Higgs might not be as weird as it looked in July. Researchers seem to have found some previously missing decay products: tau leptons and b-particles. If the new data had shown that these were still missing, we might be looking at a Higgs boson showing some unexpected favoritism in how it interacts with the two main classes of particle, fermions and bosons.
Here’s Strassler’s summation. Note the inclusion of the Tevetron collider, which may be turned off, but still has plenty of data analysis fun left to go.
ATLAS, CMS and the Tevatron have updated some of their measurements (though a few updates are noticeably missing). The main new result that there is now considerable evidence that the new particle is not a pseudoscalar (i.e. negative parity) particle, which means it remains consistent with a Standard Model-like Higgs particle. Meanwhile there are no significant deviations from the expectations for a Standard Model-like Higgs particle — the ones that were hinted at before have either evaporated (for now) or remain unchanged. Also, there is now increasing evidence that the strengths with which this particle interacts with W and with Z particles are in just the ratio one would expect for a Higgs particle of some type; this is a crucial test of whether it is a Higgs or not.
It will be years before we have the precision to really put a nail in the Higgs. And note that a Standard Model Higgs boson — fitting in with our current scheme of particles and particle relationships — is maybe not such a good thing. That is, we have a lot of mysteries in the universe (dark energy, say, or supersymmetry) that don’t appear to fit with that Standard Model. In a sense, we’re looking for a way out of that model. A weird Higgs boson would be just that.
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