Dr Judd Harrison

Published: 16 November 2021

Theoretical b Quark Physics

Judd Harrison photo

Dr Judd Harrison
School of Physics & Astronomy

UKRI Stephen Hawking Fellowship, October 2021 – September 2025

Area of Research

Theoretical b Quark Physics


Why did you choose to pursue a fellowship in your research career?

After completing my PhD at the University of Cambridge, I moved to Glasgow for my first post-doc. Here, I was lucky to work within the world renowned HPQCD lattice collaboration and had the opportunity to develop my own ideas. I was encouraged to apply for early career fellowships in order to develop these ideas further, and so decided to pursue a Stephen Hawking Fellowship with the support of the University.

Why work at the University of Glasgow?

The Particle Physics Theory Group at the University of Glasgow is home to a thriving community of lattice theorists, producing world leading research in topics broadly aligned with my own. At Glasgow I have the opportunity to benefit from collaboration and shared expertise as part of this group, while also being supported in developing my own portfolio of independent world leading research. On top of this, I have secured supplementary LKAS funding from the University of Glasgow, which I will use to support a PhD student to work on my research programme and related topics. Stephen Hawking Fellowships also support public engagement activities – and the University of Glasgow, with its culture of public engagement and extensive ties to the local community, offers excellent support for this aspect of my project as well.

How would you describe your research in 20 words or less?

I am studying the decays of b quarks in order to find where our understanding of nature breaks down.

What is your research highlight?

So far, the achievement I am most proud of is my world first study of Bc to J/psi decay using full lattice QCD. Using new methods, I was able to investigate the full kinematic range of the decay, something which had not previously been tractable using lattice QCD for this or related processes.

What do you look for in a collaboration?

Collaborations are a great opportunity to develop new skills, gain experience in something unfamiliar, and make contacts in different research communities. As such I like to look for smaller collaborative projects, involving maybe only a handful of researchers, working on topics outside my own area of expertise, where I can bring something new and valuable to the table and learn a lot in the process.

How do you see your research impacting society?

There have been many recent hints from experiments such as the Large Hadron Collider that new physics might be detectable indirectly through its impact on the decays of b quarks. My research will provide the theory inputs needed to disentangle and identify possible new physics effects appearing in these decays, and ultimately help us to deepen our understanding of fundamental physics. My research also relies heavily on the use of high-performance computing (HPC) facilities here in the UK. Together with numerous other HPC projects, this drives the development of new computing technology, for example faster and more power efficient CPUs and storage, which then feed directly into devices such as phones and laptops.

What next?

Until very recently lattice QCD calculations of b quark decays have largely neglected the effects of electromagnetism, so incorporating these effects into my work is something I want to develop in the future. On top of this, I plan to extend the methods I have developed to include decays in which the final state is unstable – this poses additional theoretical challenges but would allow me to study a whole new set of decays which are very important experimentally.

First published: 16 November 2021