Vincenzo Cavasinni & Paolo Rossi 
Three articles by Bruno Pontecorvo (1955-1956) [PDF ebook] 
The beginning of Particle Physics at the Dubna SynchroCyclotron

This volume presents three papers by Bruno Pontecorvo translated from the original Russian edition. The physics results discussed in the papers have been obtained by Pontecorvo in the years 1955-56 at the synchrocyclotron of Dubna, in USSR, a proton accelerator that, at that time, was the most powerful particle-machine in the world. Thanks to the large energy available, important results have been obtained using secondary beams of charged pions interacting with hydrogen and deuterium. A detailed analysis of the data collected is presented in terms of the theoretical models available at that time, based on “Partial Waves Analysis” of the interaction cross sections. Moreover, a reanalysis of the negative-pion- proton cross-sections presented in the introduction, proves the existence of the Δ0-baryon particle, a member of the baryonic decuplet of the SU(3) symmetry group. The Δ-baryon family (Δ++, Δ+, Δ0, Δ-) represented an important milestone for the following developments in particle physics: the Gell-Mann Zweig quark-model and the introduction of the “color”: the new quantum number of the strong interaction theory: the “Quantum Chromodynamics”.
Translated from Russian edition by Gil Pontecorvo, JINR, Dubna
Introduction by Vincenzo Cavasinni and Paolo Rossi, Universit´a di Pisa