The Higgs boson is one of the final puzzle pieces required for a complete understanding of the standard model of physics—the so-far successful theory that explains how fundamental particles interact with the elementary forces of nature.
The so-called God particle was proposed in the 1960s by physicist Peter Higgs to explain why some particles, such as quarks—building blocks of protons, among other things—and electrons have mass while others, such as the light-carrying photon particle, do not. Higgs's idea was that the universe is bathed in an invisible field similar to a magnetic field. Every particle feels this field—now known as the Higgs field—but to varying degrees.
If a particle can move through this field with little or no interaction, there will be no drag, and that particle will have little or no mass. Alternatively, if a particle interacts significantly with the Higgs field, it will have a higher mass. The idea of the Higgs field requires the acceptance of a related particle: the Higgs boson. According to the standard model, if the Higgs field didn't exist, the universe would be a very different place, said SLAC's Peskin, who isn't involved in the LHC experiments.
Buried beneath the French-Swiss border, the Large Hadron Collider is essentially a 17-mile-long (27-kilometer-long) oval tunnel. Inside, counter-rotating beams of protons are boosted to nearly the speed of light using an electric field before being steered into collisions. Exotic fundamental particles—some of which likely haven't existed since the early moments after the big bang—are created in the high-energy crashes. But the odd particles hang around for only fractions of a second before decaying into other particles.
Theory predicts that the Higgs boson's existence is too fleeting to be recorded by LHC instruments, but physicists think they can confirm its creation if they can spot the particles it decays into. If, based on these observations, the Higgs does turn out to have a mass of around 125 GeV, as previous evidence suggested, the result would help explain why the God particle has avoided detection for so long.
This mass is just high enough to be out of reach of earlier, lower-energy particle accelerators, such as the LHC's predecessor, the Large Electron-Positron Collider, which could probe to only about 115 GeV. At the same time 125 GeV is not so massive that it produces decay products so unusual that their detection would be clear proof of the Higgs's existence. In reality the Higgs appears to transform into relatively commonplace decay products such as quarks, which are produced by the millions at the LHC.
To detect the Higgs's signal amid this high background noise, scientists must calculate very precisely what the distribution of a particular decay particle for a collision will be at a given energy, and how many extras of that particle they'd expect to see if a Higgs boson has been created. Additionally, to ensure that a signal is not a statistical fluke, LHC physicists require lots of collisions—the atom smasher can produce about 800 million per second—to generate enough Higgs-creating collisions.
.Source : http://news.nationalgeographic.com/news/2012/07/120703-higgs-boson-god-particle-cern-science/
http://atlasexperiment.org/atlas_photos/lhc/lhc.html
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