PI: Chris Allton

FASTSUM continued its work on studies in QCD at non-zero temperature, non-zero chemical potential, analysis of the symmetry properties of QCD and studies of centre vortices

In addition to our previous results, we have broadened our investigation of QCD into several complementary directions. We have studied QCD at non-zero chemical potential, 𝜇≠0, obtaining new estimates of the curvature of the pseudo-critical temperature T_C with 𝜇 and thereby extending our understanding of the phase structure away from zero density. These studies provide further quantitative control over the behaviour of strongly interacting matter under extreme conditions.

We have also continued our detailed analysis of the heavy meson spectrum, focusing on bottomonium. By tracking modifications of bottomonium states across temperatures, we gain insight into in-medium effects and the persistence of bound. This forms a bridge between first-principles lattice calculations and experimental heavy-ion phenomenology.

Alongside these spectrum studies, we have pursued a series of symmetry-based investigations. In particular, we have examined the fate of the U(1)_A symmetry at finite temperature and its role in shaping the structure of the QCD transition. We have also explored the role of centre vortices in confinement, analysing how topological degrees of freedom contribute to non-perturbative phenomena. Complementary studies in lower-dimensional theories have provided additional theoretical control, allowing us to isolate and better understand the mechanisms at work in four-dimensional QCD.

Finally, we have generated our Generation 3 ensembles and have begun extracting physical observables from them. These new ensembles significantly enhance the systematic precision and temperature coverage of our programme.

The figure below, the curvature of the pseudo-critical temperature T_C with baryonic chemical potential, 𝜇_B, is shown.