Neutrons and protons do not "touch" each other in the atomic nucleus in the way macroscopic objects do. Instead, they interact through the strong nuclear force, which is one of the fundamental forces in nature.
The strong nuclear force is responsible for holding the nucleus together despite the repulsive forces between protons. It is a short-range force that acts within the nucleus and is much stronger than the electromagnetic force, which is responsible for the repulsion between protons.
The strong nuclear force binds protons and neutrons together in the nucleus. It is a force between particles called nucleons (protons and neutrons) and is mediated by particles called mesons. The strong force acts equally on protons and neutrons, but it is slightly more attractive for neutrons due to their lack of electric charge.
The strong nuclear force overcomes the electrostatic repulsion between protons by effectively "gluing" the nucleons together. It binds the protons and neutrons so that they are contained within the nucleus.
Although the strong nuclear force is incredibly powerful at short distances, it rapidly decreases with increasing distance. As a result, it is negligible outside the nucleus and does not directly influence the behavior of electrons or their interactions with other atoms.
In summary, neutrons and protons in the atomic nucleus do not collide in the classical sense. Instead, they interact through the strong nuclear force, which binds them together despite the electrostatic repulsion between protons. The strong force acts at very short distances and is responsible for the stability of the nucleus.