Pre-studies for the HIBEAM Beamline

Research Project, 2025 – 2026

The European Spallation Source (ESS) will open a unique new discovery window for fundamental particle physics. This application is for the continued design and costing of the HIBEAM instrument for the ESS. HIBEAM is led by a consortium of scientists from four Swedish institutions working with the international HIBEAM collaboration. Building on a preliminary design that already enables key experiments, such as the world´s first high-sensitivity search for free neutrons converting to antineutrons for thirty years, the physics program of HIBEAM will be broadened. This includes design modifications for a high-sensitivity neutron electric dipole moment search and quantification of the discovery potentials for a range of phenomena such as anomalous forces. A key feature of HIBEAM is the annihilation detector for a neutron-antineutron search. Detector prototypes have been constructed and will be tested at low-energy particle facilities and at the ESS for detector performance and spallation background estimations. This is symbiotic with work on the further development of detector simulation and data analysis techniques. Additional key aims of the grant are continued collaboration growth and development of links with Swedish industry. The overarching goal of this work is a design report to enable a fully costed and competitive proposal for a instrument under Swedish leadership for the ESS.