Higgs discovery further explained

Let’s be clearer on the meaning of the claims made earlier this month:

“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...

“The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela.

CMS is, of course, the Compact Muon Solenoid experiment at CERN’s LHC. They’ve issued their own press statement, which illuminates further:

CMS observes an excess of events at a mass of approximately 125 GeV with a statistical significance of five standard deviations (5 sigma) above background expectations. The probability of the background alone fluctuating up by this amount or more is about one in three million.

And the ATLAS particle physics experiment at LHC, in its own press statement,

...puts the significance of the signal at 5 sigma, meaning that only one experiment in three million would see an apparent signal this strong in a universe without a Higgs.

Now, pardon me while I warp over to a universe without a Higgs to confirm that. (I may be some time.)