Chen Ning Yang, Weak Interactions, and Parity Violation

Resources with Additional Information · Yang Honored

C.N. Yang
Courtesy of
National Laboratory

Chen Ning Yang shared the 1957 Nobel Prize for Physics with Tsung Dao Lee "for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles".  “Yang and Lee made a fundamental theoretical breakthrough of non-conservation of parity. Because of the their work, all science theories based on parity had to be reexamined.”1

Lee and “Yang, then of Brookhaven [National Laboratory (BNL)], interpreted results of particle decay experiments at Brookhaven's Cosmotron particle accelerator and discovered that the fundamental and supposedly absolute law of parity conservation had been violated.” 2

“Yang overturned Paul … Dirac's deceptively natural assumption that the best know [sic] elementary particle possessed no feature, which would permit a distinction between right and left. Yang's revision of the question of right and left symmetry in element particle reactions began with the discovery of a new kind of particle, called a meson. He explained that symmetry laws generate the law of conservation. The law of right-left symmetry contributed to the formulation of the law of conservation of parity in 1924. Eventually, this law of conservation was extended to other aspect of physics. After the discovery of a fundamental problem with the law of parity, Yang and Lee wrote a paper titled "Question of Parity Conservation in Weak Interactions." In this paper, they suggested a series of experiments that would test their hypothesis that there were certain decay paths in weak particle interactions that were preferred and that remained constant despite the reversal of other relevant parameters. They also reexamined the consequences of removing the parity law for radioactive disintegration of nuclei and particles.” 1

1 Edited excerpts from Chen Ning Yang
2 Edited excerpts from Parity Violation


Resources with Additional Information

Additional information about C. N. Yang, weak interactions, and parity violation is available in electronic documents and on the Web.



Additional Web pages:


Yang Honored:


Some links on this page may take you to non-federal websites. Their policies may differ from this site.