Over a month ago, experimenters at Fermilab's DZero collaboration discovered an unusual asymmetry between the annihilation of matter and anti-matter in their experiment. It was clear, just on the surface of it, that there had to be some unusual mechanism at work here beyond what the Standard Model of particle physics outlines, but it takes some time to go from new experimental evidence to a full-blown theoretical explanation.
But in this world, "some time" grows shorter and shorter. In fact, it took very little time for Bogdan A. Dobrescu, Patrick J. Fox, and Adam Martin to come up with a theoretical explanation. They submitted their paper to the arXiv on May 23, just 9 days after the May 14 announcement by Fermilab of the DZero results. (If their theory holds up, this may someday be described as a very exciting 9 days!)
And their explanation has certainly caught on, because it represents some substantial changes from the existing theory. Right now, the Standard Model has been confirmed in almost all of its particulars ... except for the elusive Higgs Boson, which is the particle which explains how objects gain mass. But according to this explanation, the DZero results can be explained if you apply supersymmetry to the situation, but it yields some unexpected results ... namely that there could be 5 different variations of the Higgs Boson, and they would interact with the known particles more strongly than physicists had previously anticipated. (The supersymmetry angle is explained in some depth by Lubos Motl, surprisingly clearly, over at The Reference Frame blog.)
In a way, linking this asymmetry to the Higgs Boson makes perfect sense. As Adam Martin of Fermilab told the BBC, "What's difficult is to have those large effects without damaging anything else we've already measured. The Standard Model fits just about every test we've thrown at it. To fit in a new effect in one particular place is not easy." But since the Higgs is the one aspect of the Standard Model that hasn't been observed yet, I guess it's the natural place to look for some new physics hiding out.
There's a lot of great coverage on this, but of them my favorite is the radio interview with an experimenter from DZero and also the two theoretical physicists who came up with this multiple Higgs interpretation. It does an excellent job of showing how scientists really think about their work, and cutting through all of the hype. The interview is an hour long, though, so not everyone may be able to devote the time to it ... but I certainly found it worthwhile.
- Higgs Boson
- Fermilab and Anti-matter Asymmetry
- ArXiv.org - CP violation in B_s mixing from heavy Higgs exchange, June 18 (latest draft at the time of this writing)
- Radio interview with researchers
- Symmetry Breaking - Could DZero result point to multiple Higgses?, June 4
- BBC - US experiment hints at 'multiple God particles', June 14
- Discover magazine - Fermilab Particle Physicists Wonder: Are There 5 Higgs Bosons?, June 15
- The Telegraph - The 'God particle' may exist in five forms, Large Hadron Collider's rival project finds, June 15
- Not Even Wrong blog - God Particles Breeding Like Bosons, June 15
- National Geographic - "God Particle" May Be Five Distinct Particles, New Evidence Shows, June 16
- Discovery News - The Higgs Boson May Have 'Five Faces', June 21
- The Reference Frame - Five Faces of the Higgs, June 21
- Symmetry Breaking - Possible multiple Higgs role in matter-antimatter balance gets a blessing, June 22