Text Box: Reviewed 9 November 2007 Requests for clarifications to eugenesittampalam (at) gmail.com – most welcome!
Text Box: The quantity referred to, in quantum mechanics, as 'spin' is sometimes regarded as the most 'quantum-mechanical' of all physical quantities, so we shall be wise to pay some attention to it. … For an electron, proton, or neutron, the amount of spin is always ħ/2, that is just one-half of the smallest possible value that Bohr originally allowed for his quantized angular momenta of atoms... and, in a sense, ħ/2 is itself the more fundamental basic unit. Roger Penrose (Professor of Mathematics, University of Oxford), The Emperor's New Mind, Oxford University Press, NY, 1990; p 341
Text Box: In 1987 the European Muon Collaboration, which had been scattering muons off polarized protons at CERN, shocked the particles physics community with the announcement [J. Ashman et al., Phys. Lett. B 206, 364 (1988); Nucl. Phys. B 328, 1 (1989)] that little or none of the proton's spin can be attributed to the spins of its three constituent quarks... That report precipitated what became known as "the spin crisis." ... WHERE DOES THE PROTON REALLY GET ITS SPIN? Robert L. Jaffe (Professor of Physics, Center for Theoretical Physics, MIT), Physics Today, September 1995; pp 24-30