Research on supernova explosion revealed

BRITISH FESTIVAL OF SCIENCE:THIS SUMMER we waited for final word that the Higgs particle exists. Now scientists have come up with yet another particle that may help solve one of the greatest mysteries of the universe.

This as yet unproven particle only exists on paper, the result of intense mathematical computations that describe its behaviour. And as with the discovery of the Higgs boson, Cern – Europe’s nuclear research centre – has stepped forward, offering help to prove that the particle exists.

Details of the work were presented yesterday on the opening day of the annual British Festival of Science, taking place in Aberdeen. University of Aberdeen physicist Prof Charles Wang said the work, in which he was a team member, relates to the universe’s single most dramatic event: a supernova stellar explosion.

Only the Big Bang that formed the universe was bigger than these explosions which occur only about once a year across the entire cosmos, he said. Yet so powerful are they that for a short time while exploding they throw off more light on their own than the rest of the stars in all of the galaxies combined.

There are two types: one where two stars collide, the other where a star collapses before exploding. “Why some of these explosions occur has been unresolved by astrophysicists for 50 years,” said Prof Wang.

The key issue is how these mighty supernovas get the energy to cause such a cataclysm. Scientists have a good idea what is inside stars as they age, possibly to become the next supernova. There is plenty of material in these massive nuclear furnaces to make a decent explosion but certainly not of the order of a supernova.

This led the research team to the conclusion that there must be a missing ingredient, something that could add that much more bang for the cosmological buck. Surprisingly, what they came up with in some ways looks like the Higgs, said Prof Wang. “The theory for the new particle has similarities to the Higgs boson.”

So far it has no name but Prof Wang called it a “gravitational scalar particle” and while the Higgs gives mass to particles with which it interacts, this new scalar seems to have an influence on gravity.

The special thing about the particle is that it can only exist in the huge heat and energy generated inside a star when it is about to supernova, he said.

Once formed they “act like a mechanical shock wave with 100 per cent efficiency”, he said. “They have a specific structure to enable the transfer of energy in the supernova.”

Once formed it seems to amplify the explosive capacity of the star up to the status of a supernova.

Details of their theory were published recently in the journal Physics Letters B, and Cern has intervened to help locate the particle using its Isolde experiment. This may be able to reach the huge energy levels needed by smashing together radioactive particles. It remained unclear whether it could also reach the energy densities needed to make the particle come to life, said Prof Wang.

Coverage of the festival continues daily in The Irish Times and irishtimes.com