Speaker
Description
The parton structure of the proton can be studied mainly using two types of hard scattering processes: exclusive processes, giving access to Generalised Parton Distributions (GPDs), and semi-inclusive processes, described in terms of Transverse Momentum Dependent parton distributions (TMDs). In full QCD no relations exist between GPDs and TMDs. However, a connection between T-odd effects related to TMDs and GPDs was found in simple models [1].
In this talk, I will discuss the general features of model calculations that allow to establish this so-called lensing relation [2]. I will also discuss two specific examples in the framework of light-front quantisation: the pion, as a prototype of a two-body bound system where the lensing relation holds, and the proton, viewed as a three-body bound system, where the relation is broken.
[1] M. Burkardt, Phys. Rev. D66 (2002) 114005
[2] B. Pasquini, S. Rodini, A. Bacchetta, arXiv:1907.06950
