Weak isospin projection

In particle physics, weak isospin is a quantum number relating to the weak interaction, and parallels the idea of isospin under the strong interaction. Weak isospin is usually given the symbol T or I with the third component written as ${\displaystyle T_{\mathrm {z} }}$, ${\displaystyle T_{3}}$, ${\displaystyle I_{\mathrm {z} }}$ or ${\displaystyle I_{3}}$. It can be understood as the eigenvalue of a charge operator.

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