CANCELLED DUE TO COVID
Baryon number violation is considered a necessary condition to explain matter-antimatter asymmetry and may also play a role in accessing a hidden sector and addressing the question of dark matter. The construction of the European Spallation Source (ESS) provides a unique opportunity to exploit a high intensity beam of cold neutrons to perform searches for baryon number violation. The NNbar experiment will search for neutron-antineutron and neutron-sterile neutron oscillations with an improvement in sensitivity of several orders of magnitude compared to previous searches. An overview of the experiment and developments towards a prototype detector at Stockholm University are presented in this talk.