Researchers at the European Organization of Nuclear Research (CERN) working with the Large Hadron Collider (LHC) say they now have strong evidence of existence of the long sought after "God particle" or Higgs boson.
The Higgs boson is a subatomic particle believed to give mass to matter. In combination with gravity, it determines an object's weight.
According to The Los Angeles Times, the Higgs boson is the only particle predicted by the widely accepted Standard Model of particle physics that has not been observed.
AP reports that scientists will make a formal announcement of the results of their work on Wednesday. According to the Daily Mail, news that five of the original scientists, including Edinburgh emeritus professor Peter Higgs, who proposed the existence of the Higgs, were invited to the Wednesday event sparked speculations that the particle has been discovered.
AP reports CERN scientists say they have compiled data that shows "the footprint and shadow of the particle" even though they have not actually "seen" the particle itself. While the scientists believe that the evidence they have is sufficient for confidence that the "God particle" exists, they are being cautious about saying they have "discovered" the particle.
The standard for declaring a "discovery" in the field of particle physics is very high. It must be shown that there is a less than 1 in 1.7 million chance that the results are mistaken before the evidence can be declared a "discovery." Two independent experiments have confirmed that there is only 1 in 16,000 chance of being wrong, AP reports. This is high enough for a significant degree of confidence physicists say. But the results by two teams working independently on the problem will have to be combined for a higher level of certainty about the find. AP reports that CERN spokesman James Gillies, said on Monday, "Combining the data from two experiments is a complex task, which is why it takes time, and why no combination will be presented on Wednesday."
Theoretical physicist and professor at King's College London, John Ellis, said: "I agree that any reasonable outside observer would say, 'It looks like a discovery,'We've discovered something which is consistent with being a Higgs."
Rob Roser, who led the team searching for the Higgs boson at the Fermilab in Chicago, said scientists are stopping short of saying they have "found" the Higgs boson because, "Particle physicists have a very high standard for what it takes to be a discovery."
Roser said the evidence scientists have at the moment may be compared to a paleontologist finding the fossilized footprints of a dinosaur and concluding that the dinosaur that left the footprint must have existed. He said: "You see the footprints and the shadow of the object, but you don't actually see it."
The Los Angeles Times reports that looking for the "footprints" of a subatomic "dinosaur" involves high-energy collision experiments in which exotic particles are created that break down almost as soon as they are formed. Scientists then look for the products of the breakdown or decay as "footprints" or signature of the particle they are really looking for.
According to The Los Angeles Times, scientists working at the Fermilab Tevatron accelerator near Batavia, Illinois, reported their final results on Monday. They said while their data is not conclusive about the Higgs boson, it has come very close to it.
The Telegraph reports that results from the US Tevatron also strongly indicated the existence of the Higgs boson. The Telegraph points out that many scientists consider the fact that the results of the US Tevatron and the LHC that use different methods for searching for the Higgs boson converge, strong evidence that that their results are not just a statistical fluke. Professor Dan Tovey at the University of Sheffield said: "These intriguing hints from the Tevatron appear to support the results from the LHC shown at CERN in December. This gives us more confidence that what we are seeing is really evidence of new physics rather than just a statistical fluke. We will need to wait until Wednesday and the latest results from the LHC before getting the full picture however."
The Telegraph reports that the Tevatron results give a signal of the Higgs boson at a mass range between 115 and 135 Gigaelectronvolts (GeV). The signal has a statistical strength of 2.9 sigma, which means that there is about one in 550 chance that the result is only a statistical fluke.
According to University of Paris physicist Gregoria Bernardi, who was involved in the work at Fermilab, there were "strong indications of the production and decay of Higgs bosons" in some of the observations.
The Los Angeles Times reports the scientists seek a 99.99994% level of certainty, a benchmark known as 5-sigma. The best results using the LHC have surpassed the 4-sigma level (at about 99.994% chance).
The physicist Peter Higgs and his colleagues postulated the Higgs boson in the 1960s to explain how subatomic particles such as electrons, protons and neutrons acquired mass. The Los Angeles Times reports that physicist Joseph Lykken, Fermilab theoretical physicist, said the Higgs boson "gets at the center for some physicists, of why the universe is here in the first place." Lykken describes the Higgs field as an energy field that spreads out in the whole universe. He explained that particles moving in the Higgs field experience it as a kind of sticky molasses that slows them down and keeps them from moving at the speed of light. According to the Daily Mail, without the slowing down effect of the Higgs field, particles would travel through space at the speed of light and would, therefore, be unable to bind together to form atoms that make up material objects in the universe.
According to AP, some experts use the analogy of a snowfield to explain how the Higgs confers mass on particles. The Higgs boson is conceived of as associated with an energy field through which particles travel.The effect of the Higgs field on particles is likened to the effect on persons passing through a "snowfield" depending on whether they are wearing "skis, snowshoes or just shoes."
AP reports that the term "God particle," popular among laymen, was first coined by Nobel Prize-winning physicist Leon Lederman.
CERN said in a press release that the official announcement of the results will come on Wednesday at a physics conference in Australia. The scientists will be announcing results obtained by two teams, known as the ATLAS and CMS teams.