Photo from the Nobel Foundation archive.
The Nobel Prize in Physics 1949
Born: 23 January 1907, Tokyo, Japan
Died: 8 September 1981, Kyoto, Japan
Affiliation at the time of the award: Kyoto Imperial University, Kyoto, Japan, Columbia University, New York, NY, USA
Prize motivation: "for his prediction of the existence of mesons on the basis of theoretical work on nuclear forces."
Prize share: 1/1
Atomic nuclei consist of protons and neutrons held together by a strong force. Hideki Yukawa assumed that this force is borne by particles and that there is a relationship between the range of the force and the mass of the force-bearing particle. In 1934, Hideki Yukawa predicted that this particle should have a mass about 200 times that of an electron. He called this particle a "meson". Mesons' existence was verified in later experiments.