Speaker
Description
The internal structure of hadrons can be described in terms of structure functions that encode, for example, the momentum and spin distributions of their constituents. Parton distribution functions (PDFs) and Transverse Momentum Distributions (TMDs), for example, describe the quark and gluon momentum distributions inside a hadron. These distribution functions are, however, not easy to calculate, because they are defined on the light front, whereas most hadron calculations are performed in a Euclidean metric.
To address this, we are developing a new method to compute PDFs and TMDs from hadronic matrix elements within a non-perturbative functional framework based on Dyson–Schwinger and Bethe–Salpeter equations (DSE/BSE). As a first step, we illustrate the method in a simplified model consisting of two interacting scalar particles of equal mass.
Within this setup, we employ a handbag approximation for the matrix element. The calculation incorporates both the two-body Bethe–Salpeter amplitude—obtained from its corresponding equation—and the four-scalar scattering amplitude, computed from its scattering equation. This framework allows us to access both valence and sea contributions in a unified manner.