Posted: Tuesday, August 23, 2011
Results from the ATLAS and CMS collaborations, presented at the biannual Lepton-Photon conference in Mumbai, India, today, show that the elusive Higgs particle, if it exists, is running out of places to hide. Proving or disproving the existence of the Higgs boson, which was postulated in the 1960s as part of a mechanism that would confer mass on fundamental particles, is among the main goals of the LHC scientific program. ATLAS and CMS have excluded the existence of a Higgs over most of the mass region 145 to 466 GeV with 95 percent certainty.
As well as the Higgs search results, the LHC experiments will be presenting new results across a wide range of physics. Thanks to the outstanding performance of the LHC, the experiments and the Worldwide LHC Computing Grid, some of the current analyses are based on roughly twice the data sample presented at the last major particle physics conference in July.
"These are exciting times for particle physics," said CERN*'s research director, Sergio Bertolucci. "Discoveries are almost assured within the next twelve months. If the Higgs exists, the LHC experiments will soon find it. If it does not, its absence will point the way to new physics."
The Standard Model Higgs mechanism is one of a range of ways that fundamental particles could acquire their masses. According to the Higgs mechanism, space is filled with a so-called Higgs field with which particles interact. Those that interact strongly with the field have more mass than those that interact weakly, rather like a streamlined racing car cuts through air more easily than a bus.
At the first major particle physics conference of 2011, the European Physical Society's High Energy Physics conference held in Grenoble, France, in July, both ATLAS and CMS were careful to stress that possible hints of a Higgs signal in their data could be explained by statistical fluctuations. Now, with additional data analyzed, the significance of those fluctuations has slightly decreased.
"Thanks to the superb performance of the LHC, we have recorded a huge amount of new data over the last month," said ATLAS spokesperson Fabiola Gianotti. "This has allowed us to make great strides in our understanding of the Standard Model and in the search for the Higgs boson and new physics."
CMS Spokesperson Guido Tonelli concurred, saying: "It's great that the LHC's fantastic performance this year has brought us this close to a region of possible discovery. Whatever the final verdict on Higgs, we're now living in very exciting times for all involved in the quest for new physics."
The Lepton-Photon conference runs until 27 August. There will be a press conference on 25 August at which CERN Director General, Rolf Heuer, will be one of the speakers. CERN's LHCb experiment will present its latest measurements on the Standard Model on Saturday 27 August. Following the Lepton Photon conference, the results from the LHC experiments will be available through the CERN website.
The LHC is on track to at least double the amount of data delivered so far to the experiments by the end of the year.
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*CERN, the European Organization for Nuclear Research, is the world's leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. One candidate for accession: Romania. India, Israel, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have Observer status.
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