The difference between a hadron and a dark energy particle lies in their fundamental properties and roles in the universe:
Hadron: A hadron is a type of particle that experiences the strong nuclear force, which is one of the fundamental forces in nature. Hadrons are composed of quarks, which are elementary particles that come in different flavors (such as up, down, strange, charm, bottom, and top). Protons and neutrons, which are the building blocks of atomic nuclei, are examples of hadrons. Hadrons can be further classified into two categories: baryons, which consist of three quarks (e.g., protons and neutrons), and mesons, which are quark-antiquark pairs (e.g., pions and kaons). Hadrons are influenced by all fundamental forces except gravity.
Dark Energy Particle: Dark energy is a concept in cosmology that describes the mysterious force driving the accelerated expansion of the universe. It is believed to constitute a significant fraction of the total energy density of the universe. However, the nature of dark energy is still largely unknown. Dark energy is not associated with particles in the same way as hadrons are. Instead, it is often treated as a property of spacetime itself or as an energy associated with vacuum fluctuations.
While hadrons are familiar particles within the framework of the Standard Model of particle physics, dark energy particles, if they exist, would be outside the realm of this model. Dark energy is hypothesized to have a negative pressure, driving the expansion of the universe, but its precise nature and the possible existence of particles associated with it are subjects of ongoing research and exploration.
In summary, hadrons are particles composed of quarks that experience the strong nuclear force, while dark energy refers to an unknown form of energy driving the accelerated expansion of the universe and does not have a well-established particle description.