What is the significance of the conservation of lepton number in particle physics?

The conservation of lepton number in particle physics is important because it helps to explain why certain particles exist and why certain interactions occur. Lepton number conservation ensures that the total number of leptons (such as electrons and neutrinos) remains constant in a given reaction, which helps to maintain the stability and balance of fundamental particles in the universe. Violations of lepton number conservation could lead to new discoveries and insights into the nature of particle interactions.