No, we cannot see individual quarks within protons and neutrons directly. The reason is that quarks are confined within particles due to a phenomenon called color confinement, which is a fundamental aspect of the strong nuclear force.
The strong nuclear force is responsible for holding quarks together inside protons and neutrons. This force is extremely strong, but it has a peculiar property known as asymptotic freedom. Asymptotic freedom means that at very high energies or short distances, the strong force weakens, allowing quarks to behave almost as free particles. However, as they move apart, the strong force between them increases rapidly.
Because of this behavior, when scientists attempt to separate individual quarks from protons or neutrons by providing high-energy inputs, they instead create additional quark-antiquark pairs due to the strong force. This results in new particles forming, making it impossible to isolate an individual quark.
Additionally, quarks are always found in combinations that satisfy a property called color neutrality. Quarks come in three "colors" known as red, green, and blue, and combinations of quarks must result in an overall color-neutral state. For example, a proton consists of three quarks—two "up" quarks and one "down" quark—which combine to form a color-neutral particle. The strong force ensures that quarks always remain in color-neutral combinations.
Although we cannot observe individual quarks directly, scientists have inferred their existence and properties through indirect methods, such as high-energy particle collisions and scattering experiments. These experiments provide insights into the behavior of quarks and the strong force, contributing to our understanding of particle physics and the Standard Model.