Protons and neutrons do not "touch" each other in the sense of direct physical contact within the atomic nucleus. Instead, they are bound together by the strong nuclear force, which is one of the fundamental forces in nature.
The atomic nucleus is a densely packed region at the center of an atom where protons and neutrons are located. The strong nuclear force, also known as the strong interaction or strong force, is responsible for holding the nucleus together. It is an extremely powerful force that overcomes the electromagnetic repulsion between protons, which would otherwise cause the nucleus to disintegrate.
The strong nuclear force acts between quarks, which are the elementary particles that make up protons and neutrons. Protons and neutrons are each composed of three quarks. In a proton, the quarks consist of two up quarks and one down quark, while in a neutron, there are two down quarks and one up quark.
The strong nuclear force binds the quarks together within each proton and neutron, creating a stable structure. Additionally, the force acts between neighboring protons and neutrons, helping to hold the nucleus together as a cohesive unit.
It's important to note that the strong nuclear force has a very short range, which means it only operates effectively within the atomic nucleus. Beyond the nucleus, other forces, such as electromagnetic forces, dominate the interactions between particles.