The distinction between elementary particles and massive objects, such as dark matter, lies in the nature of their interactions with other particles and forces in the universe.
Elementary particles, as the name suggests, are considered fundamental building blocks of matter. These particles, such as electrons, quarks, and neutrinos, are not composed of smaller constituents and are considered point-like entities in our current understanding of physics. They have mass because they interact with the Higgs field, which permeates the universe. The Higgs field gives rise to the Higgs boson, a particle associated with the mechanism by which other particles acquire mass. The interaction between elementary particles and the Higgs field determines their mass.
On the other hand, dark matter is a term used to describe a form of matter that does not interact with light or other electromagnetic radiation, hence the term "dark." It does not emit, absorb, or reflect light, making it difficult to directly detect. The presence of dark matter is inferred through its gravitational effects on visible matter and the large-scale structure of the universe.
The nature of dark matter is still an active area of research, and its exact composition remains unknown. However, the leading candidates for dark matter include hypothetical particles that are much more massive than elementary particles. These particles, if they exist, would interact very weakly with ordinary matter, which makes them difficult to detect directly.
While elementary particles have mass due to their interactions with the Higgs field, the properties of dark matter particles, including their mass, are yet to be fully understood. The absence of direct evidence for massive objects or dark matter detection arises from the fact that dark matter particles, if they exist, do not interact strongly with electromagnetic radiation and interact weakly with ordinary matter, making them challenging to observe or detect through conventional means. Scientists continue to investigate dark matter through a variety of experimental approaches and theoretical models to better understand its properties and origin.