Chung-Yao Chao (Chinese: 赵忠尧; pinyin: Zhào Zhōngyáo; 27 June 1902 – 28 May 1998) was a Chinese theoretical physicist. He studied the scattering of gamma rays in lead by pair production in 1930, without knowing that positrons were involved in the anomalously high scattering cross-section. When the positron was discovered by Carl David Anderson in 1932, confirming the existence of Paul Dirac's "antimatter", it became clear that positrons could explain Chung-Yao Chao's earlier experiments, with the gamma rays being emitted from electron-positron annihilation.