The Higgs boson (sometimes nicknamed the "God particle" in popular media) is a hypothetical massive elementary particle that is predicted to exist by the Standard Model (SM) of particle physics. The Higgs boson is an integral part of the theoretical Higgs mechanism. If shown to exist, it would help explain why other particles can have mass. It is the only predicted elementary particle that has not yet been observed in particle physics experiments. Theories that do not need the Higgs boson also exist and would be considered if the existence of the Higgs Boson was ruled out. They are described as Higgsless models.
If shown to exist, the Higgs mechanism would also explain why the W and Z bosons, which mediate weak interactions, are massive whereas the related photon, which mediates electromagnetism, is massless. The Higgs boson is expected to be in a class of particles known asscalar bosons. (Bosons are particles with integer spin, and scalar bosons have spin 0.)
Experiments attempting to find the particle are currently being performed using the Large Hadron Collider (LHC) at CERN, and were performed at Fermilab's Tevatron until its closure in late 2011. Some theories suggest that any mechanism capable of generating the masses of elementary particles must be visible at energies below 1.4 TeV; therefore, the LHC is expected to be able to provide experimental evidence of the existence or non-existence of the Higgs boson.
Watch those videos that explains the Higgs Boson: