How is it that a particle, such as a fermion, can have 1/2 spin? Why do bosons have integral spin? Also why are up, down, charm, strange, top, and bottom quarks named the way they are?

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anonymous · Answer

Truth be told know one knows why this should be, and until we do, it will just be one of those things.  String Theorists would like to believe that all particle properties are determined by the vibrational modes of one dimensional strings vibrating through a multidimensional landscape. Thus the spin state of a fermion or boson will be froma  specific vibrational mode of that string.

The quark names were just a convention at first.  Originally, when there were only two known quarks (the up and down), they were named after the components of their isospin (which are opposite to each other).  The strange quark was named because it was discovered to be a component of "strange" particles (Which at the time had unexplainable or strange properties, having been discovered before the quark model was created).  The charm quark was called charm, because it brought symmetry back into the theory (the charm being a partner of the strange), and hence was named the "charmed particle" by its proposers.  Finally the top and bottom names were not very imaginative, and chosen as logical compliments to the up and down.  They do have other (more imaginative) names though which have fallen out of use (which is a shame).  These two quarks are also known as Truth and Beauty.