Work Package 8
The second ESS source will generate very cold neutrons with 1000 times the intensity of any other facility on Earth. This has great importance for fundamental physics, which is often reliant on detecting incredibly rare particle behaviour in support of new theories: the greater the particle intensity, the greater the chance of spotting such behaviour. Led by Stockholm University in Sweden, this work package will provide a conceptual design for an experiment called NNBAR that will search for neutron–antineutron conversions. These conversions would provide the first experimental evidence for the violation of so-called baryon number. Baryon number violation is needed to explain the universe today is dominated by matter, with very little antimatter.
The experiment probes mass scales beyond those available at any collider and, in addition to addressing the matter-antimatter problem, could provide evidence for topical theories of new physics such as supersymmetry and extra dimensions. NNBAR is an international collaboration. The fundamental experimental goal is to provide a sensitivity to neutron to antineutron conversions with a sensitivity improvement of three orders of magnitude compared with earlier work. The unique nature of the Large Beam Port at the ESS together with advances in neutronics drive this improvement.