## Physics: Principles with Applications (7th Edition)

Quarks and antiquarks have spin $\frac{1}{2}$, and these can be aligned or anti-aligned. A combination of 3 quarks and antiquarks gives a spin magnitude of either $\frac{1}{2}$ or $\frac{3}{2}$. A combination of a quark and an antiquark gives a spin magnitude of either 0 or 1.