The pion
El pion (mesón pi)
- Date
- 1947 · confidence high
- Place
- University of Bristol, England, United Kingdom (emulsions exposed at Pic du Midi)
- Credited to
- Cecil Powell; César Lattes; Giuseppe Occhialini
- People
- 👤 Cecil Frank Powell1903–1969👤 César Lattes1924–2005👤 Giuseppe Occhialini1907–1993
- Field
- Cosmos & Earth
What was discovered
In photographic emulsions exposed at high altitude, a particle is observed that decays into a muon: Yukawa's meson that mediates the nuclear force. It resolves the confusion with the muon and inaugurates hadron physics.
Lattes carried out the key exposures in Chacaltaya (Bolivia); Nobel Prize awarded only to Powell in 1950.
What it led to
- Hadron physics and meson accelerators
- Confirmation of Yukawa's theory
- Strange particles (kaons, 1947) and the 'particle zoo'
- Quark model
Built on
- Yukawa's meson theory and the discovery of the muon1935-1937
- Yukawa's theory
- Nuclear emulsion technique
Made possible
- Pion therapy (experimental)
- Meson factories (LAMPF, TRIUMF)