China has joined the hunt for antimatter with a pair of anti-neutrino detectors deep in a hillside near Hong Kong, particle physicists said.

Twin detectors installed for the Daya Bay Reactor Neutrino Experiment are recording interactions of anti-neutrino particles produced by powerful reactors at the China Guangdong Nuclear Power Group power plant located about 35 miles from Hong Kong.

The experiments is part of an international effort to study basic properties of matter and why matter predominates over antimatter in the universe, says a U.S. researcher involved in the search.

Theories say equal portions of matter and antimatter should have been created during the big bang, University of Wisconsin-Madison physics Professor Karsten Heeger says, but matter now predominates.

"Right now there is not a good understanding of what causes the matter-antimatter imbalance in the universe," he says. "We live in a world of matter and don't know where all the antimatter went."

The large size and sensitivity of the detectors at Daya Bay will provide the best opportunity to date to collect enough anti-neutrinos to help solve the conundrum, a UWM release said Monday.

"This is a remarkable achievement after eight years of effort -- four years of planning and four years of construction -- by hundreds of physicists and engineers from around the globe," Yifang Wang of the Institute of High Energy Physics of the Chinese Academy of Sciences said in the statement.