Monday, 29 December 2014

Revamped Hadron Collider targets mysteries of universe

ex the oz page 6,  29.12.14

Revamped Hadron Collider targets mysteries of universe

SCIENTISTS have begun the process of restarting the Large Hadron Collider, the world’s most powerful particle accelerator, after a $185 million upgrade that could help to solve some of the universe’s greatest mysteries.
The improvements to the LHC, based at Cern, Europe’s particle physics centre near Gen­eva in Switzerland, mean its two proton beams — each with a diameter less than a third that of a human hair — will now contain energy equivalent to the detonation of 154 tons of TNT.
Experts hope the additional power will allow them to explore aspects of high-energy physics — such as dark matter, the suspected existence of new fundamental particles and an explanation of gravity.
It may even be possible to produce microscopic black holes.
Two years ago, a less powerful version of the LHC discovered the Higgs boson, the elusive “God particle” that is a part of the process that is believed to give matter its mass.
Confirmation of the particle’s existence led to Peter Higgs — emeritus professor of physics at Edinburgh University, who first suggested its existence in 1964 — being jointly awarded last year’s Nobel Prize for Physics.
The old machine’s limitations prevented physicists from investigating all of the Higgs boson’s properties, or exploring other aspects such as the cause of the Big Bang — the explosion of energy 13.7 billion years ago that is thought to have given birth to the universe.
The LHC, which has a circumference of 27km, was shut down in February last year for upgrade work.
“We have unfinished business with understanding the universe,” said Tara Shears of Liverpool University, who leads a team working on the LHC to investigate antimatter, thought to have been created in equal amounts to matter in the Big Bang, but which largely ­disappeared.
“We want to see what the new data shows us about antimatter and why there’s so little of it. We want to chase the hints we’ve seen in previous measurements at lower energies, whose behaviour didn’t match our expectations, in case these turn into discoveries.”
For non-scientists, the power of the improved LHC, which uses magnets to accelerate bunches of subatomic particles — protons — to near-light speed, is hard to comprehend.
Each proton has the energy of a mosquito, but each bunch contains 115 billion protons and has as much energy as a 150kg motorbike moving at 150km/h.
The aim is to smash the beams together to recreate conditions similar to those existing billionths of a second after the Big Bang.
There is a possibility that these high energies could see the LHC making its own dark matter — the invisible particles of which 27 per cent of the mass of the universe is believed to comprise.
For Cern, perhaps the most sensitive issue is the suggestion, backed by some scientists, that the upgraded LHC could produce destructive new forms of matter, such as microscopic black holes.
It commissioned a study showing that although this was theoretically possible, any black holes created under Geneva would have no resemblance to those popularised by films such as Interstellar, which depicts them bending time and space. Instead they would instantly disintegrate, leaving Switzerland mercifully unscathed.
The opportunity to test such theories will come in March when the beams are switched back on, but scientists are ­already testing other parts of the LHC and the smaller particle ­accelerators linked to it.
The most radical change for the male-dominated Cern is not the LHC upgrade, however. It is the decision to appoint the first female director-general in its 60-year history. Fabiola Gianotti will start in the role in 2016.
The Sunday Times

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