In experimental particle physics, missing energy refers to energy that is not detected in a particle detector, but is expected due to the laws of conservation of energy and conservation of momentum. Missing energy is carried by particles that do not interact with the electromagnetic or strong forces and thus are not easily detectable, most notably neutrinos. In general, missing energy is used to infer the presence of non-detectable particles and is expected to be a signature of many theories of physics beyond the Standard Model.