For 10 points, name this quantum number introduced to explain the difference between a proton and a neutron.
In a single J shell, for even values of the angular momentum this quantity is equal to one, while for odd angular momentum it is zero. For light nuclei and negligible Coulombic effects, the square of its quantum number approximately commutes with the Hamiltonian. One projection of this quantity is equal to the charge minus half the sum of strangeness and baryon number. Because strong interactions are invariant under rotations within the space defined by this property, it follows by Noether's theorem in that it is conserved in strong interactions. Its symmetry, like the symmetry of a similar property, is approximated by the SU(2) group and that symmetry follows from up and down quarks having almost the same mass. For 10 points, name this quantum number introduced to explain the difference between a proton and a neutron.
In a single J shell, for even values of the angular momentum this quantity is equal to one, while for odd angular momentum it is zero.
isospin