A Sino-US matter of great import

PUBLISHED : Monday, 29 August, 2011, 12:00am
UPDATED : Monday, 29 August, 2011, 12:00am


Why is there something rather than nothing, the great 17th-century philosopher and mathematician Leibniz famously asked. Physicists may be close to getting an answer from experiments being performed at the Daya Bay nuclear power plant.

An international team of physicists and engineers, led by American and Chinese scientists and which includes Hong Kong academics, is trying to measure a mystery feature of neutrinos, a fundamental building block of matter, and their evil twin, antineutrinos. The neutrinos are by-products of nuclear reactions, hence the need to perform the experiments at the Daya Bay nuclear plant.

In an example of Sino-US co-operation, the US Department of Energy has provided US$68 million to finance half the cost of the Daya Bay study, with China paying the rest.

Results from the experiments, which began this month, may explain why in a universe full of antimatter, matter exists at all, or, as Leibniz might put it, why the universe is biased towards having something instead of nothing.

This involves an arcane concept called broken symmetry. According to the Big Bang Theory, the early universe was so hot that it was just energy. As it expanded and cooled, the energy was converted into matter and antimatter. But this symmetry had to be broken in order for matter to predominate.

The Daya Bay experiments will complement those being performed at the large hadron collider at Cern, near Geneva. Cern scientists are looking for what is called the Higgs boson, a hypothetical elementary particle that gives matter mass.

One of the finest creations of the human intellect, particle physics is driving humankind towards answering its deepest questions.