Mesons and Antimesons

The known mesons and antimesons, eight in number, are listed in Table 20-2. The kaons are the antiparticles of the antikaons, and the two charged pions are antiparticles of one another. The neutral pion is its own antiparticle, and the eta particle is its own antiparticle. All of the mesons are unstable their decay reactions will be discussed in Section 20-8. 

The pions and kaons were discovered in experiments with cosmic rays, and their properties have been determined by use both of cosmic rays and of high-energy particles produced by particle accelerators. The pions were discovered by Powell and his collaborators, as mentioned in Section 20-3. The kaons were discovered about 1950 by many investigators. 

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