The Higgs boson is otherwise known as the God particle.
Find out what the theory behind the Higgs particle is and what role it is thought to play in the universe.
What is it?
The Higgs boson is a theorised sub-atomic particle that is believed to confer mass.
It is conceived as existing in a treacly, invisible field that stretches across the Universe. Higgs bosons "stick" to fundamental particles of matter, dragging on them.
Some of these particles interact more with the Higgs than others and thus have greater mass. But particles of light, also called photons, are impervious to it and have no mass.
Why is it important?
The origin of mass (meaning the resistance of an object to being moved) has been fiercely debated for decades.
Finding the Higgs boson would vindicate the so-called Standard Model of physics, a theory that developed in the early 1970s, which says the universe is made from 12 particles which provide the building blocks for all matter.
These fundamental particles are divided into a bestiary comprising six leptons and six quarks, which have exotic names such as "strange," "up", "tau" and "charm."
Why is it called the Higgs boson?
The name comes from a British physicist, Peter Higgs, who conceived of a field of mass-confering particles while walking in Scotland's Cairngorm Mountains in 1964.
Important theoretical work was also done by Belgian physicists Robert Brout and Francois Englert.
Bosons are non-matter particles which are force carriers, or messengers that act between matter particles.
The interaction gives rise to three fundamental forces - the strong force, the weak force and the electromagnetic force. There is a fourth force, gravity, which is suspected to be caused by a still-to-be found boson named the graviton.
How has the Higgs been hunted?
The quest to prove, or disprove, the Higgs has been carried out at particle colliders: giant machines that smash protons together and sift through the sub-atomic debris that tumbles out.
The biggest of these is the Large Hadron Collider (LHC), operated by the European Organisation for Nuclear Research (CERN) in a ring-shaped tunnel underground near Geneva.
Smash ups generated at the LHC briefly generate temperatures 100,000 times hotter than the Sun, replicating the conditions that occurred just after the universe's creation in the Big Bang nearly 14 billion years ago.
But these concentrations of energy, while violent, occur only at a tiny scale.
Evidence to support the existence of the Higgs is indirect.
In the same way that we can cannot see the wind, we infer its existence and strength from leaves or flags or other objects that it moves.
Why the "God Particle"?
The Higgs has become known as the "God particle," the quip being that, like God, it is everywhere but hard to find.
In fact, the origin of the name is rather less poetic.
It comes from the title of a book by Nobel physicist Leon Lederman whose draft title was The Goddamn Particle, to describe the frustrations of trying to nail the Higgs.
The title was cut back to The God Particle by his publisher, apparently fearful that "Goddamn" could be offensive.