Neutrinos from Diffuse Supernova Background

Neutrinos are the second most abundant particles in the universe according to the Standard Model, yet they are the least likely to interact. This feature implies that detecting a neutrino can reveal valuable insights into its source. Among the known sources of neutrinos, core-collapse supernovae are one of the most efficient factories. On average, a single collapse occurs every second in the observable universe, emitting approximately $10^{58}$ neutrinos. The total flux of neutrinos reaching Earth from all core-collapse supernovae across the universe is the diffuse supernova neutrino background (DSNB). Detection of the DSNB is just around the corner. This guaranteed flux of astrophysical neutrinos encodes information about the whole supernova population, including an answer to a currently unsolved question about the rate at which black holes form from massive stars. This chapter discusses the ingredients entering the DSNB calculation as well as current experimental limits and hints.