A new particle consistent with the long-sought Higgs boson has been observed by the ATLAS and CMS experiments at CERN.
Both ATLAS and CMS see a strong indication for the presence of a new particle in the mass region around 125-126 GeV. Both experiments gave the level of significance of the result as 5-sigma on the scale that particle physicists use to describe the certainty of a discovery – a 5-sigma result is considered a discovery.
“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 outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage but a little more time is needed to prepare these results for publication.”
“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 spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”
The results are based on data collected in 2011 and 2012, with 2012 data still under analysis –publication of the analysis is not expected until the end of July. A more complete picture of the observations will emerge later this year after the LHC provides the experiments with more data.
CERN Research Director Sergio Bertolucci said: “It’s hard not to get excited by these results. We stated last year that in 2012 we would either find a new Higgs-like particle or exclude the existence of the Standard Model Higgs. With all the necessary caution, it looks to me that we are at a branching point; the observation of this new particle indicated the path for the future towards a more detailed understanding of what we’re seeing in the data.”
The next step is to determine the precise nature of the particle and its significance for our understanding of the universe. Positive identification of the characteristics will take considerable time and data – but whatever form the Higgs takes, our knowledge of the fundamental structure of matter is about to change.
The Standard Model describes the fundamental particles from which every visible thing in the universe is made of and the forces acting between them – but this makes up only 4% of the total. A more exotic version of the Higgs particle could be a bridge to understanding the remaining 96%.
“We have reached a milestone in our understanding of nature,” said Rolf Heuer, CERN Director General. “The discovery of a particle consistent with the Higgs boson opens the way to more detailed studies requiring larger statistics, which will pin down the new particle’s properties, and is likely to shed light on other mysteries of our universe.”