Archive of historical materials
Note by Shoichi Sakata: Interaction among Heavy Quanta and Heavy Particles
OU1937-A5 (8 pages) Date: None
Yukawa and his co-researcher, Shoichi Sakata, were preparing the paper, “On the Interaction of Elementary Particles II.” This note is a draft of the main section of that paper and it was written by Shoichi Sakata. (The contents of this note correspond with the sections 2 through 4 in the final version of the paper.) Sakata used note paper printed with “Osaka Imperial University, Department of Physics.” It is interesting to note that Sakata wrote the paper in Japanese and Yukawa produced the English manuscript based on Sakata’s paper. The English text on pages 2 and 4 was written by Yukawa. Sakata wrote Japanese in block letters. He wrote each character carefully so the note is very easy to read. Sakata’s handwriting contrasts sharply with Yukawa’s cursive writing.
Sakata’s manuscript was a lecture manuscript, but it was so logically consistent that it alone served as an excellent review. Yukawa must have valued Sakata’s skill to write well-organized papers. Based on the interaction Hamiltonian of heavy particles (protons, neutrons) and heavy quanta (mesons), Sakata determined the matrix elements that described a variety of processes and then used them to derive the exchange force between a neutron and proton (Yukawa potential). Furthermore, he calculated the force between protons, force between a proton and a neutron, and force between neutrons as high-order (4th-order) quantum effects. Yukawa and Sakata assumed that heavy quanta (mesons) had either a positive or negative charge. They were not aware of the existence of heavy quanta (mesons) with zero charge at that time. (Written by Yutaka Hosotani)
