A New Approach to Hadron Structure from Lattice QCD

by Andrea Shindler

Wednesday 28 Oct 2026, 14:00 → 16:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Parton distribution functions (PDFs) describe how the momentum of a hadron is distributed among its constituent quarks and gluons and are essential ingredients in the interpretation of high-energy scattering experiments. While PDFs are primarily determined through global analyses of experimental data, lattice QCD offers a complementary, first-principles approach through the calculation of their moments.

For decades, however, the calculation of higher PDF moments on the lattice has been obstructed by severe renormalization and operator-mixing problems, as well as by the deterioration of the signal-to-noise ratio as the moment order increases. These difficulties have severely limited the information that can be obtained using conventional methods.

In this colloquium, I will introduce a new approach based on the gradient flow that overcomes the longstanding renormalization and mixing problems while also improving the statistical signal. By defining local operators at positive flow time, one can avoid power-divergent mixing and establish a systematic connection between lattice observables and physical PDF moments through perturbative matching in the continuum. In principle, this framework makes moments of arbitrarily high order accessible to lattice QCD.

I will present recent numerical results for pion and nucleon structure, illustrating both the progress achieved and the challenges that remain. I will compare the lattice results with moments obtained from global PDF analyses and discuss the precision that could be achieved with current state-of-the-art statistics in lattice QCD simulations.