The attraction between the positively charged protons and the nucleus in an atom is a result of the strong nuclear force, which is one of the fundamental forces of nature. While protons carry a positive charge, they are also subject to the strong nuclear force, which overcomes the electrostatic repulsion between protons and holds the nucleus together.
The strong nuclear force is responsible for binding the protons and neutrons within the atomic nucleus. It is an extremely powerful force, but it has a very short range, acting only at distances smaller than the size of an atomic nucleus. The strong force is mediated by particles called gluons, which carry the force between quarks (the elementary particles that make up protons and neutrons).
Within the nucleus, protons and neutrons are made up of three quarks each. The strong force acts between these quarks, holding them together and thus binding the protons and neutrons within the nucleus. The overall effect of the strong nuclear force is that it overcomes the electromagnetic repulsion between the positively charged protons, allowing them to be held together within the atomic nucleus.
It's important to note that the electromagnetic repulsion between protons does play a role in determining the size of the nucleus and the overall stability of atoms. The balance between the repulsive electromagnetic force and the attractive strong nuclear force is crucial for maintaining the integrity of atomic nuclei and the stability of matter as we know it.