Editing Elementary particle (section)

==== Higgs boson ====
{{Main|Higgs boson}}

Although the weak and electromagnetic forces appear quite different to us at everyday energies, the two forces are theorized to unify as a single [[electroweak force]] at high energies. This prediction was clearly confirmed by measurements of cross-sections for high-energy electron-proton scattering at the [[Hadron Elektron Ring Anlage|HERA]] collider at [[DESY]]. The differences at low energies is a consequence of the high masses of the W and Z bosons, which in turn are a consequence of the [[Higgs mechanism]]. Through the process of [[spontaneous symmetry breaking]], the Higgs selects a special direction in electroweak space that causes three electroweak particles to become very heavy (the weak bosons) and one to remain with an undefined rest mass as it is always in motion (the photon). On 4 July 2012, after many years of experimentally searching for evidence of its existence, the [[Higgs boson]] was announced to have been observed at CERN's Large Hadron Collider. [[Peter Higgs]] who first posited the existence of the Higgs boson was present at the announcement.<ref>
{{cite news
 |first=Lizzy |last=Davies
 |date=4 July 2014
 |title=Higgs boson announcement live: CERN scientists discover subatomic particle
 |url=https://www.theguardian.com/science/blog/2012/jul/04/higgs-boson-discovered-live-coverage-cern
 |newspaper=[[The Guardian]]
 |access-date=2012-07-06 |df=dmy-all
}}</ref> The Higgs boson is believed to have a mass of approximately {{val|125|u=GeV/c2}}.<ref>
{{cite web
 |first=Lucas |last=Taylor
 |date=4 Jul 2014
 |title=Observation of a new particle with a mass of 125 GeV
 |url=http://cms.web.cern.ch/news/observation-new-particle-mass-125-gev
 |publisher=[[Compact Muon Solenoid|CMS]]
 |access-date=2012-07-06 |df=dmy-all
}}</ref> The [[statistical significance]] of this discovery was reported as 5&nbsp;sigma, which implies a certainty of roughly 99.99994%. In particle physics, this is the level of significance required to officially label experimental observations as a [[Discovery (observation)|discovery]]. Research into the properties of the newly discovered particle continues.