The Higgs boson is a fundamental subatomic particle whose existence was predicted in a series of papers in 1964 by a group of theoretical physicists including Robert Brout, François Englert, Peter Higgs and Tom Kibble. The prediction was made partly on aesthetic grounds – by which I mean it was introduced to make the equations that describe how subatomic particles interact with each other more elegant. (...)
Its job is to give mass to the other fundamental particles, including the electrons and quarks out of which we are made. It does this by interacting with them, and the strength of the interaction determines the mass of the particle; electrons are less massive than top quarks because they interact more weakly with Higgs particles. The Higgs particles fill all of space. Every cubic meter of the room in front of you is crammed with Higgs particles. They occupy all of the space inside your body, outside your body, and throughout and between every galaxy in the observable universe.
How did the Higgs particles get there? The answer is not yet known but it is thought that they “condensed out” into the universe less than a billionth of a second after the Big Bang as the universe expanded and cooled. This is a process not dissimilar to ice crystals forming on a cold window on a frosty morning. Water vapour in the air undergoes what physicists call a phase transition when it comes into contact with the cool glass. The symmetry of the vapour state is broken and the intricate structural forms of ice crystals spontaneously emerge. This happens because it is energetically favourable; at low enough temperatures, water molecules can release energy by bonding together into clumps, rolling down a metaphorical hill and settling into a valley floor. Similarly, the “empty” vacuum of space has a lower energy when filled with a condensate of Higgs particles, which is ultimately the explanation for why there is any large-scale structure in the universe at all.
This sounds odd and it gets odder. If we naively calculate the energy locked up in the Higgs condensate, it is bordering on the absurd. In every cubic meter of space the condensate stores 1037 joules, which is more energy than the sun outputs in 1,000 years. This should blow the universe apart but it doesn’t, for reasons that nobody understands.
The discovery of the Higgs is more than a profound vindication of advanced mathematics and its application in theoretical physics. It is also a surprising engineering and political achievement. No single nation is prepared to invest in a project as technically difficult and high-risk as the Large Hadron Collider. The machine itself is 27 kilometres in circumference and is constructed from 9,300 superconducting electromagnets operating at -271.3°C. There is no known place in the universe that cold outside laboratories on earth; in the 13.75 billion years since the Big Bang occurred, the universe is still roughly 1° warmer than the LHC. This makes it by far the largest refrigerator in the world; it contains almost 120 tonnes of liquid helium.
Buried inside the magnets are two beam pipes, which, at ultra-high vacuum, contain circulating beams of protons travelling at 99.9999991 per cent the speed of light, circumnavigating the ring 11,245 times every second. Up to 600 million protons are brought into collision every second, and in each of these tiny explosions, the conditions that were present less than a billionth of a second after the Big Bang are re-created. Four giant detectors, known as ATLAS, CMS, LHCb and ALICE, diligently observe each collision, searching for new physical phenomena such as the Higgs, searching for a needle in a thousand haystacks.
In order to construct and operate this group of complex, interdependent machines, more than 10,000 physicists and engineers from 608 institutes in 113 countries collaborate with each other for the sole purpose of enhancing our knowledge of the universe.
by Brian Cox, New Statesman | Read more:
Illustration by Ralph Steadman
Buried inside the magnets are two beam pipes, which, at ultra-high vacuum, contain circulating beams of protons travelling at 99.9999991 per cent the speed of light, circumnavigating the ring 11,245 times every second. Up to 600 million protons are brought into collision every second, and in each of these tiny explosions, the conditions that were present less than a billionth of a second after the Big Bang are re-created. Four giant detectors, known as ATLAS, CMS, LHCb and ALICE, diligently observe each collision, searching for new physical phenomena such as the Higgs, searching for a needle in a thousand haystacks.
In order to construct and operate this group of complex, interdependent machines, more than 10,000 physicists and engineers from 608 institutes in 113 countries collaborate with each other for the sole purpose of enhancing our knowledge of the universe.
by Brian Cox, New Statesman | Read more:
Illustration by Ralph Steadman
