Quarks and electrons are considered elementary particles in the Standard Model of particle physics, which means they are believed to be point-like particles with no internal structure or size. According to our current understanding, quarks and electrons are indivisible and have no spatial extent.
The concept of "size" in particle physics is related to the spatial distribution of a particle's charge or energy density. For composite particles like protons and neutrons, which are made up of quarks, one can talk about their size based on the spatial distribution of the quarks within them. However, for fundamental particles like quarks and electrons, the notion of size becomes less meaningful since they are considered to be point particles.
Mass, on the other hand, is a fundamental property of particles and is not directly related to their size. In the context of elementary particles, mass is a measure of the amount of intrinsic energy a particle possesses. The Higgs mechanism in the Standard Model is responsible for giving mass to elementary particles like quarks and electrons. The Higgs field interacts with these particles and provides them with mass, but this mass is not directly tied to their size in terms of spatial extent.
It's important to note that the concept of size can become more complicated in the context of quantum field theory, where particles are described as excitations of underlying fields. These fields can exhibit certain properties that are analogous to size, such as their spatial extent or correlation lengths, but these properties are not the same as the size of a classical object.