sterile neutrinos

Sterile neutrinos are a hypothetical type of neutrino that do not interact with normal matter through the weak nuclear force, unlike the known active neutrinos. They are proposed to help explain certain phenomena in particle physics and cosmology, such as the observed imbalance between matter and antimatter in the universe. While active neutrinos come in three types associated with the known charged particles (like electrons), sterile neutrinos are like a hidden fourth type. Detecting them could provide insights into dark matter and the fundamental laws of physics, but as of now, there is no experimental evidence for their existence.