Physicists claim to have found the reason for missing antimatter in universe

March 19th, 2008 - 2:27 pm ICT by admin  

London, March 19 (ANI): A team of physicists claims to have found the first ever hint as to where did all the missing antimatter in the universe disappear to, attributing the reason to a flipping particle.

According to a report in New Scientist, the cosmos was a cauldron of radiation and equal amounts of matter and antimatter in its early days. As it cooled, all the antimatter annihilated in collisions with matter - but for some reason the proportions ended up lopsided, leaving some of the matter intact.

Physicists think that the explanation for this lies with the weak nuclear force, which differs from the other fundamental forces in that it does not act equally on matter and antimatter. This asymmetry, called CP violation, could have allowed the matter to survive to form the elements, stars and galaxies we see today.

But this standard model, which is the best effort to describe the universe’s structure, fails to fully explain CP violation.

Many alternative theories claim to have the answer, such as those incorporating supersymmetry, extra dimensions and hitherto unseen forces. However, they often invoke new particles, and experiments have yet to turn up evidence of these.

Particle physicists have long thought that they might find such evidence in a particle called the Bs meson, which comprises a bottom antiquark bound to a strange quark.

The Bs is one of a handful of mesons that transforms into its own antiparticle and back again 3 trillion times per second before decaying into other particles.

These oscillations between matter and antimatter make it a good place to look for evidence that CP violation goes beyond the standard model.

At the Tevatron particle accelerator at Fermilab in Batavia, Illinois, two groups of scientists running the rival CDF and D-Zero experiments have been studying several properties of Bs mesons and their oscillations by picking through the debris created when protons and antiprotons collide.

While each experiment on its own has found faint hints of CP violation above and beyond the standard model, the experimental uncertainties have been too large to make a definitive claim.

Now, Luca Silvestrini at Italy’s National Institute of Nuclear Physics (INFN) in Rome and colleagues in Italy, France and Switzerland have managed to reduce these uncertainties. By combining the published results of the CDF and D-Zero teams, they have shown there seems to be much more CP violation than the standard model permits.

“We can say with greater than 99.7 per cent probability that CP violation is there,” said Silvestrini. (ANI)

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