Monday, July 4, marks 10 years since one of the most celebrated scientific breakthroughs of the 21st century: the discovery of the Higgs boson, a particle that is key to understanding the universe.
What is the Higgs boson?
A tiny particle that explains how things get their mass.
British physicist Peter Higgs theorised in 1964 that particles whizzing around the universe pick up their mass by travelling through an invisible field — a bit like a vehicle ploughing through snow.
But there was a missing piece of the puzzle. If the Higgs field existed, there should be a special particle — or boson — associated with it: the Higgs boson.
In 2012, physicists found it, completing one of science’s most important jigsaws and proving the existence of the Higgs field.
Why is it called the Higgs boson?
Peter Higgs, now 93, is the scientist whose theories sparked the 48-year search for the particle.
Bosons are named after SN Bose, an Indian physicist who corresponded with Albert Einstein.
It has also been labelled the “God particle”, although many scientists are said to dislike the term.
When was it discovered and when is the 10th anniversary?
The breakthrough was declared on July 4, 2012, by scientists at Cern, the vast physics laboratory in Switzerland where Tim Berners-Lee invented the World Wide Web in 1989.
In a cautious but excited statement, Cern scientists said they had found a new particle consistent with the properties they would expect of Higgs.
The following March, they announced that it was indeed believed to be a Higgs boson, based on further data analysed since the initial discovery.
But Cern regards the particle’s initial discovery in 2012 as the defining moment, meaning the anniversary falls on Monday, July 4, 2022.
Peter Higgs and fellow physicist Francois Englert were awarded the Nobel Prize in 2013 for their work on the mass theory.
How was it discovered?
Cern is home to the Large Hadron Collider, the 27-kilometre pipe in which particles are flung at each other at nearly the speed of light.
It started up in 2008 and was the first of its kind powerful enough to generate enough evidence for the Higgs — which is produced in about one in every billion of these collisions.
A forerunner, the Large Electron-Positron Collider, had run throughout the 1990s without finding the Higgs boson.
The LHC had a false start after a magnet failure put its operations back by a year.
The Higgs particle has a lifespan of less than a billionth of a trillionth of a second, but decays into other particles such as photons which give the game away.
It took more than two years for enough clues to be gathered, but a key statistical threshold was reached on July 4, 2012, that made it virtually impossible that the results indicating the Higgs were coming about by chance.
How has the discovery helped us?
The discovery of the Higgs boson was a milestone in our understanding of the world around us, opening up new areas of research for physicists at Cern.
More broadly, Cern credits the push for the Higgs boson with generating spin-off benefits in cancer treatment and aerospace.
It says further benefits to humanity might materialise in future, like how the discovery of electricity had seismic effects that could hardly have been predicted at the time.
What is being done to mark the anniversary?
Scientists have been invited to Cern on Monday to reflect on the work done since Higgs and consider the future of physics.
A day later, the LHC will whirr back into life after more than three years of upgrades and maintenance, in what is known as its third run.
Intended to run for almost four years, the latest experiments will probe deeper into the nature of the Higgs boson, while also probing other mysteries of the universe such as dark matter.