scmp: Daya Bay shines light on dark matter

Daya Bay shines light on dark matter

Stephen Chen Updated on Mar 09, 2012 http://tinyurl.com/86xvrwa

An international team led by mainland scientists announced in Beijing yesterday that it had discovered a new form of elementary particle behaviour at Guangdong's Daya Bay nuclear power plant. Scientists said the observation had led to the determination of an elusive scientific constant that may eventually shed light on the whereabouts of dark matter, the invisible hypothetical matter thought to account for a large part of the total mass of the universe. The breakthrough at Daya Bay showcases China's scientific muscle in the frontiers of research and has Nobel Prize-winning potential, according to some commentators. Professor Wang Yifang , spokesman for the Daya Bay Reactor Neutrino Experiment, told a press conference at the Chinese Academy of Sciences' Institute of High Energy Physics in Beijing yesterday that they won a neck-and-neck race with France and South Korea to discover a new type of neutrino transformation. And they had also determined the crucial scientific constant behind the behaviour. The neutrino, an electrically neutral and weakly interacting subatomic particle, is known to oscillate from one state of existence to another. But the latest observed transformation happens to only about 10 per cent of neutrinos. Professor Cao Jun, a researcher with the institute and a key member of the team, said the discovery cleared one of the biggest remaining obstacles in the search for dark matter. Scientists could now confidently put up affordable experiments to verify CP violation, a theory that explains why most of the dark matter vanished after the Big Bang that created the universe, he said. "It is a scientific milestone for China," Cao said. About 250 scientists from six countries including the United States and Russia have been involved in the project. Starting in 2007, the researchers dug underground tunnels near the reactor and set up some of the world's most sensitive detectors. Hong Kong scientists from Chinese University and the University of Hong Kong designed and built subsystems for detector monitoring, background measurement and data acquisition, among other contributions. binglin.chen@scmp.com