The concept of size becomes quite complex when we delve into the subatomic realm. The Higgs boson, a fundamental particle associated with the Higgs field, is indeed very small; however, in the quantum world, there are particles that can be considered ‘smaller’ in a different sense.
One category of particles that could be described as smaller than the Higgs boson includes the various types of quarks and leptons, which are the fundamental building blocks of matter. For instance, the up and down quarks, which combine to form protons and neutrons, are considered to be point-like particles. These quarks are constituents of protons and neutrons, which make up atomic nuclei, and they are smaller than composite particles such as the Higgs boson.
Moreover, particles like neutrinos are incredibly light and elusive. Their masses are much smaller than that of the Higgs boson, making them significant when discussing the mass hierarchy of fundamental particles.
Ultimately, defining ‘smaller’ in the world of particles can often refer to mass or the scale at which they exist rather than physical size. In the quantum field, what matters more is the interactions and properties of these particles rather than their size in the conventional sense.