HIBEAM & NNBAR

HIBEAM/NNBAR is a broad experimental programme in fundamental neutron physics at the European Spallation Source (ESS), designed to exploit the unprecedented intensity and unique time structure of the ESS neutron source to search for physics beyond the Standard Model.

The programme includes world-leading searches for neutron conversion processes, such as neutron-antineutron and neutron-to-sterile-neutron transitions. The observation of such processes would provide evidence for baryon number violation, one of the necessary conditions for baryogenesis, and could help explain the origin of the observed matter-antimatter asymmetry in the Universe.

In addition to neutron conversion searches, the HIBEAM programme is developing novel experiments to search for ultralight axion-like particles (ALPs) using neutron Ramsey interferometry, with the potential to improve existing laboratory limits by several orders of magnitude. Furthermore, the programme includes the development of a next-generation neutron electric dipole moment (nEDM) experiment, providing complementary probes of CP violation and new physics.

The HIBEAM programme combines advanced neutron optics, magnetic shielding and control, and state-of-the-art detector technologies. The ultimate NNBAR experiment aims to improve the sensitivity to free neutron-antineutron oscillations by up to three orders of magnitude compared with the previous world-leading search performed at the Institut Laue-Langevin (ILL) in the early 1990s.

For further information about research opportunities, degree projects, and collaboration activities, please contact:

Valentina Santoro: valentina [dot] santoro [at] fysik [dot] lu [dot] se (valentina[dot]santoro[at]fysik[dot]lu[dot]se)