The HIBEAM Instrument at the European Spallation Source

TL;DR

The paper presents the design and scientific goals of the HIBEAM instrument at the European Spallation Source, aiming to explore fundamental particle physics phenomena with a dedicated neutron beamline.

Contribution

It introduces a novel neutron instrument at ESS with capabilities for rare particle physics searches and detailed descriptions of its design and scientific potential.

Findings

Design of a dedicated beamline and neutron optical system

Potential to search for free neutron to antineutron conversion

Capability to investigate sterile neutrons and dark matter candidates

Abstract

The European Spallation Source (ESS) will be the world's brightest neutron source and will open a new intensity frontier in particle physics. The HIBEAM collaboration aims to exploit the unique potential of the ESS with a dedicated ESS instrument for particle physics which offers world-leading capability in a number of areas. The HIBEAM program includes the first search in thirty years for free neutrons converting to antineutrons and searches for sterile neutrons, ultralight axion dark matter and nonzero neutron electric charge. This paper outlines the capabilities, design, infrastructure, and scientific potential of the HIBEAM program, including its dedicated beamline, neutron optical system, magnetic shielding and control, and detectors for neutrons and antineutrons. Additionally, we discuss the long-term scientific exploitation of HIBEAM, which may include measurements of the neutron electric dipole moment and precision studies of neutron decays.