In particle physics, SU(2) symmetry refers to the special unitary group of degree 2. This symmetry is associated with the electroweak interaction, which unifies the electromagnetic and weak forces.
The electroweak theory is based on the principle of gauge symmetry, where gauge fields are introduced to describe the forces between particles. In the case of the electroweak theory, the gauge symmetry group is SU(2) × U(1), where SU(2) corresponds to the weak force and U(1) corresponds to the electromagnetic force.
In SU(2) symmetry, particles are organized into doublets, which are pairs of particle states that transform under the SU(2) group. These doublets typically consist of a particle with a certain electric charge and its corresponding neutrino. The electroweak theory predicts that the weak force is mediated by three gauge bosons: the W+, W-, and Z^0 bosons.
The dynamics of the SU(2) symmetry involve the exchange of these gauge bosons. When particles interact through the weak force, they can change from one member of the doublet to another. This process is called "flavor oscillation" or "flavor changing." However, it is important to note that the exchange of the gauge bosons does not represent a change in the vibration direction of a fundamental quantum field itself. Rather, it describes the exchange of virtual particles that mediate the interactions between particles.
In summary, SU(2) symmetry in particle physics is a mathematical framework that describes the behavior of particles under the weak force. It involves the exchange of gauge bosons to account for processes like flavor oscillation, where particles within a doublet can transition between different states.