Here is a factfile on the Higgs boson, which unlocked the 2013 Nobel Prize on Tuesday for physicists Peter Higgs of Britain and Francois Englert of Belgium:
What is it?
The Higgs boson is a sub-atomic particle that confers mass on matter. Without it, the Universe would have no substance and life would not exist.
It was theorised 48 years ago to explain a nagging scientific anomaly -- why some particles have mass and others, like photons (light particles), have none.
The boson is thought to act like a fork dipped in syrup and held up in dusty air. While some dust slips through cleanly, most becomes sticky -- effectively acquiring mass. With mass comes gravity, which pulls particles together even as the Higgs bosons themselves decay into other particles.
The bosons are believed to exist in a molasses-like, invisible field that was created in the first fractions of a second after the "Big Bang" 13.7 billion years ago and pervades the Universe.
Why is it so important?
Finding the Higgs boson vindicates the so-called Standard Model of physics, developed in the early 1970s and the most accepted theory of how the known Universe works.
It says that all matter in the Universe is made from 12 building-block particles -- six leptons and six quarks with exotic names like "strange," "up", "tau" and "charm."
These are governed by four fundamental forces: the strong force, the weak force and the electromagnetic force and gravity.
Bosons are non-matter particles and force carriers.
The Standard Theory cannot work without the Higgs conferring mass on matter as the fundamental particles by their very nature are not supposed to have mass of their own.
Why is it called the Higgs Boson?
The name comes from Higgs, today aged 84, who first published the idea of a field of mass-conferring particles in 1964.
But vital theoretical work was also done separately by Belgian physicists Robert Brout, who died in 2011, and by Francois Englert, 80, who is Higgs' co-Nobel laureate.
A month or two after Higgs' own paper, Americans Dick Hagen and Gerry Guralnik and Briton Tom Kibble proposed that the field interacted with fundamental particles such as bosons, quarks and electrons. The stronger the interaction was, the more massive the particles appeared to be.
How has the Higgs been hunted?
The quest for the Higgs has been carried out in giant collider machines that smash particles together and sift through the sub-atomic debris.
The biggest of these is the Large Hadron Collider (LHC), operated by the European Organisation for Nuclear Research (CERN) in a ring-shaped tunnel deep 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, albeit on a miniature scale.
On July 4 last year, CERN scientists said they had found a new particle that was "consistent" with the Higgs.
New data since then has been pointing to increasing certainty that the particle was indeed the Higgs. In March, CERN said two key characteristics of the particle, "spin" and "parity", matched with what a Higgs should look like.
Why "The God Particle"?
The Higgs has become known as the "God particle": like the deity it is said to be extremely powerful, exist everywhere but impossible to pin down.
In fact, the origin of the name is less poetic.
It comes from 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 changed to "The God Particle" by his publisher to avoid giving offence.