BACKGROUND:Higgs and others have worked for decades to explain how inherently massless particles could have mass
A GOOD idea is a good idea, even if it takes almost 50 years and €4 billion to prove it.
It took this level of commitment to demonstrate beyond doubt that a theory devised by British physicist Peter Higgs back in 1964 was true, in the process filling in the last puzzle piece in our understanding of how atoms, the universe and just about everything else works.
This jigsaw piece, a subatomic particle called the Higgs boson, but much better known as the so-called “God particle”, was declared discovered yesterday by physicists around the world.
Those at Cern, however, the European research centre on the French/Swiss border where the research was done, remained doggedly conservative. They insisted further proof was needed to demonstrate beyond all doubt it was the Higgs despite being 99.999 per cent sure the missing particle had finally been found.
Prof Higgs, an emeritus professor at the University of Edinburgh, was guest of honour yesterday at the meeting at Cern convened to announce the new particle.
He was one of a number of scientists credited with developing complex mathematical theories relating to parts of what is known as the Standard Theory. This grand statement in particle physics attempts to explain all of the interactions seen in the natural world. It attempts to include everything, from electromagnetism to the forces that make atoms stick together so well.
Pieces of this elaborate puzzle have been assembled bit by bit over the past century. It was revised and revised again as physicists used bigger and more powerful particle accelerators to probe the depths of the atomic nucleus. With each new generation of accelerator, new discoveries were made.
Long before it was finished, theoretical physicists began to realise all of the calculations kept saying that in their native state most of the found or theorised particles in the puzzle had no mass. Yet how could that be given the evidence all around us that everything had mass?
Born in 1929, Higgs was a theorist who as a youngster could not decide whether to do maths or physics, as he said in an interview with The Irish Times back in 2009. Happily he chose physics.
He and others began working on theories that could explain how inherently massless particles could be made to have mass, in effect defining the shape of this missing puzzle piece even as the design of the overall puzzle was still under construction.
He proposed a particle, a boson, whose presence was first felt a trillionth of a second after the Big Bang that formed the universe. Its existence forms a field, which in turn imparts mass on other particle types existing within it.
“The initial reaction was fairly negative,” Prof Higgs admitted. “They didn’t believe me.”
The numbers came out the same time and time again, however, and eventually the reliability of the figures began to bring people around.
By 1982 his boson and field had become the Higgs boson and the Higgs field. His theory had stood the test of time, but what to do about proving it in experiments?
By then the rate of particle discovery had slowed as it became more challenging to reach accelerator energies high enough to find new things. By the mid-1990s the last of the “quarks” were discovered, leaving just one piece missing, the gap where the Higgs should be.
But, also in the 1990s, planning and construction got under way to build a new collider at Cern, one that on paper should easily be able to reach the energies at which collisions would reveal the elusive Higgs boson. By 2011 and into 2012 it routinely reached the energies where the Higgs could be produced, capturing data that delivered yesterday’s remarkable announcement – the Higgs, or something exactly like it, had finally been found.
Prof Higgs marvelled at how his theory remained largely intact. “In a way I am surprised it survived in that form. People on the whole have stuck with the theory.”
