Nuclear Physics Consolidated Grant 21-24 - University of York

The York Nuclear Physics Group is firmly positioned as one of the leading groups worldwide having recently expanded to a full complement of 14 academics with broad and connected research programmes encompassing hadron physics, nuclear structure, nuclear astrophysics, nuclear theory and applications-focussed work. Nuclear physics is one of the principal areas of research in the Department of Physics at York, where the group represents about 25% of the academic staff, and enjoys the strong support of the Department and the University in its continued development. The group carries out research in theoretical nuclear physics, as well as experimental nuclear physics which it conducts at leading facilities in Europe, North America and Japan. This consolidated grant will support the group's activities in the period 2021-2024.

To explain the context of our research, we have to describe the system we are working on - the atomic nucleus. The atoms forming our visible universe each contain an atomic nucleus, comprised of light (up, down) quarks which manifest as the familiar three-quark groupings of protons and neutrons (together known as nucleons) in a many-body quantum mechanical system. There are many open questions regarding how these nucleons arrange themselves in the nucleus: What happens when the nucleons overlap in violent collisions? Are the strong forces between nucleons the same for different combinations (pn and pp)? What is the role of three-nucleon forces? Do heavy nuclei have a "neutron skin"? These are all topics that our research will address through theoretical developments and an ambitious experimental programme at a wide range of facilities worldwide.

The range of nuclei we observe today, from light to heavy elements, was created by nuclear reactions within stars and by the violent collisions of dense stellar objects such as neutron stars. Our research addresses fundamental gaps in our knowledge of the nuclear reactions forming these nuclei in stars by reproducing these reactions here on earth, in the laboratory. We are also probing the underlying nuclear science of neutron stars. There is a lot to learn about neutron stars, it is not even established what is inside! Our group will lead investigations into the exciting possibility that a new form of matter, a hexaquark containing six quarks, could play a pivotal role.

At even smaller distance scales, we will also challenge the question of where the mass of the nucleus comes from. We know this arises from the masses of the constituent protons and neutrons. However only ~2% of this comes from the mass of the three quarks making up the nucleon. Exploring this murky quantum world through experiments at world-leading facilities will cast more light on the origins of mass.

Our nuclear physics group has a strong record in generating impact in two main areas: developing detectors for societal applications and in public engagement. This is explained more fully in the Pathways to Impact document forming part of this grant application. We expect our impact to grow strongly under the next consolidated grant. The areas we can generate impact are broad and wide-ranging:

- For homeland security, we have developed a hand-held gamma-ray detector which our industrial partner, Kromek, transformed into a wearable device called the D3S. This has been an extremely important produce for Kromek and received an order for 10,000 units from the US government. We continue to develop and improve the underlying technology.
- In medical imaging, we have developed a new (patented) approach to PET imaging, which we call quantum-entangled PET imaging (or QET). This has the potential to revolutionise PET imaging in the future and to make it easier and more affordable. We are working (under a GCRF project) with two historically-disadvantaged universities in South Africa to investigate how this could be realised to the benefit of people in developing countries.
- For nuclear decommissioning, we developed a pipeline inspection probe based on flexible silicon detector technology which we have patented and are exploiting with relevant industry.
- We work on a whole range of other application areas focussing on our key skills in radiation detection in areas including: borehole logging, mining, PET isotope production and PET isotope assay.
- In public engagement, we have achieved strong recognition for our "Binding blocks" project which engages with schoolchildren and the general public, to build a Table of the Isotopes to scale out of lego bricks. This has reached large numbers of KS5 pupils already with great success and in the next consolidated grant, we have a well-developed plan to translate this impact to the earlier KS3 and KS4.