31. But every theorist and his uncle knew that these particles had an isospin , or number, of {. 32. These nucleons are acted upon equally by the strong interaction, which is invariant under rotation in isospin space. 33. Isospin is defined in the SU ( 2 ) model while the SU ( 3 ) model defines hypercharge.34. Isospin symmetry is a subset of the flavour symmetry seen more broadly in the interactions of baryons and mesons.35. The electric charge, third component of weak isospin ( also called or ) and weak hypercharge are related by 36. Given that charge conjugation and isospin are preserved by strong interactions, so is " G ". 37. In isospin space, neutrons can be transformed into protons via SU ( 2 ) symmetries, and vice versa. 38. For example, a proton-neutron pair can be coupled in a state of total isospin 1 or 0. 39. Similar to a spin particle, which has two states, protons and neutrons were said to be of isospin . 40. By assuming that isospin was conserved by nuclear interactions, the new mesons were more easily accommodated by nuclear theory.
