Weak isospin, also known as weak isospin quantum number, is a fundamental property of subatomic particles that describes their weak interactions. T3 is the third component of the weak isospin, which determines the strength of a particle's interaction with the weak nuclear force.
Particles that have fixed weak isospin and T3 include the W and Z bosons, which are responsible for the weak nuclear force, and the left-handed fermions (quarks and leptons) in the Standard Model of particle physics.
Weak isospin and T3 are measured using experiments such as scattering experiments and particle accelerators. The values of weak isospin and T3 can also be predicted and calculated using mathematical models and equations in the Standard Model.
Particles having fixed weak isospin and T3 play a crucial role in the Standard Model as they are responsible for the weak nuclear force, one of the four fundamental forces in nature. Understanding the properties of these particles helps us to better understand the workings of the universe at the subatomic level.
Yes, weak isospin and T3 can change for a particle through weak interactions. For example, in beta decay, a neutron (T3 = -1/2) can change into a proton (T3 = +1/2) by emitting a W- boson (T3 = -1) and a beta particle (T3 = +1/2).