When two particles get close enough to each other, they don’t actually touch, because they don’t actually have surfaces. Instead, you can think of their quantum mechanical features as merging and the two particles as disappearing into another form of energy, in most cases a photon. From this energy, other kinds of particles can emerge, depending on the amount of energy you smooshed together. This is exactly what happens when we smash particles at the Large Hadron Collider to create new kinds of particles from ordinary everyday particles.
