Yoichiro Nambu of America and Janpan's Makoto Kobayashi and Toshihide Maskawa won the 2008 Nobel Prize in physics for reaching on symmetry at the microscopic level, the Nobel committee announced Tuesday.

Yoichiro Nambu was awarded "for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics." Meanwhile, Kobayashi and Maskawa were honored "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature," said the committee.

"Nambu's theories permeate the standard model of elementary particle physics. The model unifies the smallest building blocks of all matter and three of nature's four forces in one single theory," said Royal Swedish Academy of Sciences in the citation, adding that Kobayashi and Maskawa "explained broken symmetry within the framework of the standard model but required that the model be extended to three families of quarks."

Yoichiro Nambu won half the award, while Makoto Kobayashi and Toshihide Maskawa shared the other half. The trio will together share the 10 million kronor (about 1.42 million U.S. dollars) purse, a diploma and an invitation to the prize ceremonies in Stockholm on Dec. 10.

On Monday, the Nobel Medicine Prize went to France's Francoise Barre-Sinoussi and Luc Montagnier, and Harald zur Hausen of Germany for their "discoveries of two viruses causing severe human diseases."

The winners of the Chemistry Prize will be announced Wednesday, to be followed by those for Literature Thursday, Peace Friday and Economics next Monday.

The annual Nobel Prizes are usually announced in October and are handed out on Dec. 10, the anniversary of the 1896 death of Alfred Nobel, a Swedish industrialist and the inventor of dynamite.

Nobel died childless and dedicated his vast fortune to create "prizes for those, who, during the preceding year, shall have conferred the greatest benefit on mankind."

The prizes have been awarded since 1901. Each prize consists of a medal, a personal diploma and a cash award of 10 million Swedish kronor(1.42 million U.S. dollars).

(Xinhua News Agency October 7, 2008)