Cecil Frank Powell (5 December 1903 – 9 August 1969) was an English physicist who received the Nobel Prize in Physics in 1950 for heading the team that developed the photographic method of studying nuclear processes and for the resulting discovery of the pion (pi-meson), a subatomic particle.

[4] He also began to develop methods employing specialised photographic emulsions to facilitate the recording of the tracks of elementary particles, and in 1938 began applying this technique to the study of cosmic radiation,[4] exposing photographic plates at high-altitude, at the tops of mountains and using specially designed balloons,[10] collaborating in the study with Giuseppe "Beppo" Occhialini, Hugh Muirhead and young Brazilian physicist César Lattes.

This work led in 1947 to the discovery of the pion (pi-meson),[11] which proved to be the hypothetical particle proposed in 1935 by Hideki Yukawa in his theory of nuclear physics.

He acknowledged in his book, "In 1941, Bose and Chaudhuri (sic) had pointed it out that it is possible, in principle, to distinguish between the tracks of protons and mesons in an emulsion… They concluded that many of the charged particles arrested in their plates were lighter than protons, their mean mass being … the physical basis of their method was correct and their work represents the first approach to the scattering method of determining momenta of charged particles by observation of their tracks in emulsion".

[17] In 1961 Powell received the Royal Medal, and served on the Scientific Policy Committee of the European Organization for Nuclear Research (CERN) that year,[4] and in 1967 he was awarded the Lomonosov Gold Medal by the Academy of Sciences of the USSR (now Russian Academy of Sciences) "for outstanding achievements in the physics of elementary particles".

[19][20] As a result, for the first time in human history, a World Constituent Assembly convened to draft and adopt the Constitution for the Federation of Earth.

[22][23] Giuseppe Occhialini had a wooden bench built with Powell's name carved into a commemorative plaque, and then transported it to Premana, a village in the mountains above Lake Como.