At CERN, the European Particle Physics Laboratory, the ATLAS and CMS experiments presented their latest results in the search for the Higgs particle. Both experiments see strong indications for the presence of a new particle in the mass region around 125-126 GeV and a 4.9-5 sigma signal.
When the results from the two experiments are combined, they should show a 5-sigma signal and be a discovery. If this is indeed a new particle, then it must be a boson and it would be the heaviest such particle ever found.
The results presented today are preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis. Publication of the analyses shown today is expected around the end of July. A more complete picture of today's observations will emerge later this year after the LHC provides the experiments with more data.
Positive identification of the new particle's characteristics will take considerable time and data. But whatever form the Higgs particle takes, our knowledge of the fundamental structure of matter is about to be enriched.
“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “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 experiment 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."
Professor Tom Kibble CBE FRS, Emeritus Professor of Theoretical Physics at Imperial University was one of the key people involved in proposing that the Higgs boson existed and said, "It is very exciting to find that work I was involved in nearly fifty years ago is once more at the centre of attention. At the time, the Higgs boson did not seem a very significant feature of the theory, but it has become so as the last missing piece of the 'standard model'. Its discovery will complete a chapter, but not the story -- the model is amazingly successful, but many features remain to be explained."
"We have reached a milestone in our understanding of nature,"said CERN Director General Rolf Heuer. "The observation 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."
The next step will be to determine the precise nature of the particle and its significance for our understanding of the universe. Are its properties just as expected for the Higgs boson predicted in 1964, the final missing ingredient in the Standard Model of particle physics? Or is it something more exotic? The Standard Model describes the fundamental particles from which we, and every visible thing in the universe, are made, and the forces acting between them. All the matter that we can see, however, appears to be no more than about 4% of the total. A more exotic version of the Higgs particle could be a bridge to understanding the 96% of the universe that remains obscure.
"It's hard not to get excited by these results,"said CERN Research Director Sergio Bertolucci. "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 indicates the path for the future towards a more detailed understanding of what we're seeing in the data"