Gleb Wataghin and the research on penetrating showers of cosmic rays in São Paulo (1939–1949)

It is discussed the seminal experiment by Gleb Wataghin and his young assistants Marcelo Damy de Souza Santos and Paulus Aulus Pompéia, in which an unexpected component of very penetrating particles capable of crossing tens of centimeters of lead (the penetrating showers) was detected, exploring the connections between the Brazilian scenario at that time and the later developments of modern physics. Wataghin’s work at USP on cosmic rays in the period from 1939 to 1949 is also described, considering the reciprocal influence of Wataghin and Heisenberg in the search for a solution to the problem of divergences in Quantum Electrodynamics (QED), in the introduction of minimum universal length and, mainly, in the consolidation of the hypothesis of the multiple production of the particles generated in the collision of cosmic rays with the atmosphere.

Keywords:
Cosmic Showers; History of Physics; Physics in Brazil; QED