The main importance of isospin in physics is that, when particles collide or decay under the influence of the strong nuclear force, their isospin is conserved.

What is isospin of elementary particles?

Isospin. Isospin is a term introduced to describe groups of particles which have nearly the same mass, such as the proton and neutron. This doublet of particles is said to have isospin 1/2, with projection +1/2 for the proton and -1/2 for the neutron.

What is isospin formalism?

Within the MF approximation, the isospin symmetry breaking has two sources. The spontaneous breaking of isospin associated with the MF approximation itself [36,26,29] is, in this theory, intertwined with the explicit symmetry breaking due to the Coulomb interaction.