Robert Marshak

"The year 1950 saw tremendous advances in the laboratory study of mesons. It was the first year in which the accelerator physicists outdistanced the cosmic ray physicists in so far as their contributions to our understanding of the properties of mesons, the character of their production, and the nature of their interactions with nucleons are concerned. ... The cyclotron and synchrotron at Berkeley still led the procession, but Rochester and Columbia with their cyclotrons, Cornell and the Massachusetts Institute of Technology with their synchrotrons, and Illinois with its betatron were rapidly catching up."

"Dirac's argument for electric charge quantization (ECQ) is not to be taken lightly because it is the first "topological conservation law" uncovered in Abelian gauge theory. Since Dirac's two papers on the magnetic monopole were published, other potential physical examples of "topological conservation laws" have been identified in non-Abelian gauge theories (e.g. instantons, 't Hooft-Polyakov magnetic monopoles, etc.) which have revealed the rich topological structure of QCD ... Moreover, with regard to Dirac's ECQ argument, it is likely that — within the framework of the standard model — ECQ is well explained by the chiral gauge anomaly-free constraints, which, to some extent, contain topological information ..."