A new physics, or a statistical error: Round-up of news from Fermilab

Last week, JArmstrong posted to the Submitterator about the big news out of Fermilab last week. Shorter version: An analysis of 10,000 proton-antiproton collisions made in the lab's Tevatron particle accelerator turned up an anomaly that may, or may not, end up representing a very important discovery. Adding to the excitement, the Tevatron is scheduled to be shut down later this year—partly because the Large Hadron Collider is now up and running, and partly because the Tevatron program is out of money.

The response to this news has varied, with some people jumping feet-first into speculation about whether Fermilab has spotted a completely new force of nature and others expressing what might charitably be called a high level of skepticism. On Twitter, science journalist Charles Seife summed up the arched-eyebrow perspective: "My theory: #Fermilab 'discovery' is a 'budgeton': a particle that always appears -- at 3 sigma levels -- just before a machine gets shut down."

So what's it all mean? Here's what I've gleaned from reading several different accounts of the story:

• The anomaly is reported as being at "3 sigma levels", which is a way of describing the likelihood that it represents an important finding, compared to the likelihood that it's actually just showing an error in the data. This is a fairly high level of certainty, but that doesn't mean the finding is certain. In fact, findings at 3 sigma levels turn out to be nothing often enough that many physicists and physics bloggers are urging the public to not get too excited about this one. Even the people who made the discovery are a little surprised that it's getting this much attention.

• If something really has been found, it's not the Higgs Boson.

• It's going to be weeks before you hear anything more definitive. Other teams will have to run their own analysis of the Fermilab data, and see if the same anomaly turns up. Meanwhile, data from other particle accelerators will be studied to see if the anomaly shows up there, as well. Until there's confirmation that the anomaly shows up everywhere, there's not much more news to report.

• Nobody seems to be seriously speculating that a new discovery could save the Tevatron. Even if this anomaly turns out to be something that changes our understanding of particle physics, it's being discussed as a swan song, not something that could reinvigorate the program.

For more information, and a deeper understanding of the science, check out these stories:

arXiv — The full pre-press paper reporting the finding.


New York Times — The article that touched off the excitement. There's plenty of "if/then" hedging here, but a lot of that careful language is getting lost as the story circulates through other non-science-centric news sources.


LA Times — Does a nice job of explaining the odds that this anomaly will actually turn out to be something important.


Science News — There's something weird here, but don't be surprised if it turns out to be nothing.


• Discover's Cosmic Variance blog — Nice explanation of what the anomaly is, and what it could represent. Includes charts.


Physics and Physicists blog — Rumor has it that the LHC isn't seeing this anomaly in their results.


Cocktail Party Physics blog — Skeptical analysis, including some discussion about "3 sigma" results.


New Scientist — More good discussion of "3 sigma" + some context explaining how this anomaly would fit into the broader scheme of theoretical physics IF it were actually an important discovery.