Explain the spin property of quarks?

Question

Please explain in good detail to help me understand the spin property of quarks.

Answer 1

The spin property of any subatomic particle is a quantum phenomena. It is linked, to some degree, to the intrinsic angular momentum of of a particle, but as we don't consider particles to have any physical extent, the analogy can only go so far.

Essentially, spin is a purely quantum effect. We measure its influence in a number of different ways, including interactions with the system's angular momentum, magnetic fields, and even Pauli's Exclusion Principle.

Quarks are fermions, and as such would have all the above interactions (if you could isolate them). In terms of spin, they really aren't anything special. They are like electrons and protons in having a total spin of 1/2. Because of their spin, like electrons in the valence shells, quarks are also required to have antisymmetric combinations (this is the Pauli Exclusion Principle).

Its kind of a mishmash of facts, so feel free to as more directed questions.

Answer 2

See the site below

Since quarks are fermions with spin 1/2, they must obey the Pauli exclusion principle and cannot exist in identical states.

In experiments at Jefferson National Accelerator Facility in Virginia, a multinational research team has found that the spins of the proton's two up quarks (u) are aligned parallel to the overall spin of the proton, but the same is not true for the proton's down quark (d).

In order to make the experimental data on quark spin agree with theory, researchers had to take into account the once-neglected orbital motions of quarks inside the proton. Therefore, these experiments provide many new details on the behavior of quarks in the proton.