'God particle' breakthrough hailed
04/07/2012 - 15:23:19
Scientists may have finally tracked down the elusive “God particle” that gives matter mass and holds the physical fabric of the universe together.
Teams at the Large Hadron Collider (LHC), the £2.6bn “Big Bang” atom-smasher near Geneva, said they had found a new particle “consistent” with the Higgs boson.
The discovery was described today as “momentous” and “a milestone”. But the results are preliminary and more work is needed before the scientists can be sure about what they have captured.
Observations so far show it looks and acts like the long-sought particle that has eluded them for 50 years.
Finding the Higgs is vital to the Standard Model, the theory that describes the web of particles, forces and interactions that make up the universe.
Without the Higgs boson to give matter mass and weight, there could be no Standard Model universe. If it was proven not to exist, scientists would have to rip up the theory and go back to the drawing board.
Professor Peter Higgs, the retired British physicist from Edinburgh University who lent his name to the particle, heard the announcement with other scientists at a packed seminar in Geneva.
The 83-year-old professor hit on the concept of the Higgs mechanism in 1964 while walking in the Cairngorms.
Known for his unassuming nature and shunning the limelight, he wiped away a tear as the historic significance of the findings became apparent.
“I am astounded at the amazing speed with which these results have emerged,” he said. “I never expected this to happen in my lifetime and shall be asking my family to put some champagne in the fridge.”
Prof Higgs could now be eligible for a Nobel Prize.
The announcement came at the Geneva headquarters of Cern, the European Organisation for Nuclear Research, where a tense audience heard the latest progress report from the LHC.
In December last year, LHC scientists revealed they had caught the first tantalising glimpses of the particle.
But the process of proving a new piece of the universe is real is a slow and careful one, similar to getting closer to a familiar face seen from afar.
Since the initial excitement the scientists have sifted through vast quantities of data from billions of high energy collisions in an effort to reduce the chances of being wrong.
Today they confirmed that two of the LHC’s giant detectors, CMS and Atlas, had delivered results achieving the definitive “five sigma” level of proof.
A sigma is a measure of how likely it is that a finding is down to chance. At five sigma, the likelihood of a statistical fluke is one in a million.
Cern director general Rolf Heuer said: “We have reached a milestone in our understanding of nature.”
The LHC, the largest scientific instrument ever built, lies in an underground tunnel with a circumference of 17 miles which straddles the French-Swiss border near Geneva.
Protons, the “hearts” of atoms, are fired around the ring in opposite directions at almost the speed of light. When they smash together, huge amounts of energy are converted into mass and new particles created which then decay into lighter particles.
When scientists cry
Higgs bosons emerge from the maelstrom but only very fleetingly – for less than a trillionth of a second – before decaying. By tracing the decay patterns, the scientists were able to find the “fingerprint” of the Higgs.
Prof Higgs was not the only scientist to be overcome with emotion by today’s news.
Dr Kristian Harder, a CMS scientist from the Rutherford Appleton Laboratory at Didcot, Oxfordshire, said: “To be honest, I was listening to the transmission from Cern and I shed a tear.
“It may seem strange to someone not involved in particle physics that this is so important for us. This search has gone on since 10 years before I was born.”
Professor Jon Butterworth, from University College London, a member of the Atlas team, said: “We don’t know exactly what we’ve discovered but it’s fundamental, new and exciting, and it looks like the Higgs boson.
“I think it’s something so like the Standard Model Higgs that any differences will be incidental. We still need to see that it does the job the Higgs is there for, which is to give particles mass.”
Both the Atlas and CMS detectors found the new particle at a mass region of around 126 GeV (gigaelectrovolts) – exactly where the Higgs was expected to be.
In particle physics, energy and mass are interchangeable, and the mass of particles is described in terms of energy.
Finding the particle only marks the start of a new era of discovery at the frontiers of physics.
Future research may uncover more than one Higgs boson, or find better ways of describing the universe than the Standard Model.
One theory, called “supersymmetry”, calls for more than five Higgs-like particles with completely different properties.
No one can yet say whether the discovery will ever have a direct practical application. Manipulating the Higgs boson, and its associated force field, raises the futuristic prospect of controlling weight – that is, making heavy objects light and vice versa. But at present such notions are fantasy.
However, scientists believe the enormous multibillion-pound cost of searching for the Higgs can already be justified by spin-offs in areas as diverse as medicine, computing, electronics and manufacturing.
One of the most significant was the internet’s World Wide Web, which was invented at Cern to aid communication between particle physicists across the globe.
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