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2001: Scientists discover why we are here

A Californian University has thrown more light on why the Big Bang works after nearly 40 years of world-wide research.

Most scientists accept that the universe began with the Big Bang and the existence - in equal amounts - of matter and anti-matter.

The theory has been complicated by the fact that if matter and anti-matter were present in equal amounts they would cancel each other out and there would not be a universe.

Experiments by Stanford University's international team of physicists have provided the most substantial proof yet that matter and anti-matter decay at different rates and this explains the continued predominance of matter.

Charge-parity explained

This process is called charge-parity (CP) violation and derives from research in the 1950s and 1960s by theorists like Andrei Sakharov.

The evidence for CP has rested solely on - increasingly accurate - measurements of the different decay rates of the sub-atomic particle, neutral K meson and its anti-particle.

Now the team working at the Stanford Linear Accelerator Center (Slac) has observed CP violation in a heavier particle/anti-particle pair related to B meson.

They made their discovery using a 1,200 tonne detector called Babar, designed, built and operated by 600 scientists and engineers, many from the UK.

Babar forces particles to crash into each other and simulate the effects of the Big Bang deep under the Californian landscape.

The findings of the Slac team will be published in the journal Physical Review Letters.

Facts of the anti-matter


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