The Atlas and CMS teams presented their data separately in Melbourne on Wednesday, but both concluded they've discovered a new particle consistent with what they think to be a Higgs boson at a sensitivity level of sigma 5, the "gold standard" for discoveries.
"The new particle found at CERN is in the mass range of 125-126 GeV, or gigaelectronvolts, which means its mass is 125-126 times greater than the mass of a proton," explains the Wall Street Journal's Gautim Naik. Today's information is largely consistent with what CERN announced in December when they said they first glimpsed a Higgs boson.
The two team's presentations announced very similar results that are consistent with initial expectations of what a Higgs boson would look like. Just like in Tuesday's leaked video, CERN scientists seemed hesitant to call it an outright discovery on stage just yet. "We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV," said ATLAS experiment spokesperson Fabiola Gianotti, but he cautioned that more time was needed to prepare the official results. The evidence presented was enough for prominent physics bloggers Thommaso Dorigo and Matt Strassler to say it's a discovery. So, too, did Rolf Heuer, CERN's general director. He only decided to call it a discovery on Tuesday, but he was still confident in his team's findings. "I know the science, and as director general I can stick out my neck," he said according to the New York Times.
"I think we have it. Do you agree?" Heuer asked the crowd at the end of the presentation. CERN scientist Thommaso Dorigo has live blogs of the Atlas presentation and the CMS presentation that are both thorough looks at the data presented, if a little heavy on science language. Strassler's summery has a list of questions about the boson and the corresponding answers from both presentations that works as a nice side by side comparison of the two.
Reuters has a good plain language explainer of the Higgs Boson that includes a George Clooney metaphor, in case you need to be caught up. So where do we go from here? CERN is expected to publish their results by the end of the month, and they'll continue running experiments relating to the Higgs with the Large Hadron Collider until the end of the year before shutting it down until 2014 for repairs. There are still plenty of questions left unanswered, like explaining the existence of dark matter, or if there are more than one Higgs bosons. "The whole world thinks there is one Higgs, but there could be many of them," said Joe Incandela, the spokesman for the CMS team.