In 2016/2017 the COMPASS experiment collected a significant amount of data using a muon beam and a liquid hydrogen target equipped with a recoil proton detector. The data collected will allow studying several exclusive reactions, namely Deep Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP).
The most significant HEMP process is the pi0 production which represents also the highest source of background for the DVCS process. The exclusive reactions provide a unique way to study proton structure in terms of Generalized Parton Distribution functions (GPDs).
With the additional information of the parton position in the transverse plane, the GDPs can provide a 3D tomography of the proton. GPDs are also linked to the orbital angular momentum of partons and hence they can give us a deeper understanding of the dynamics inside the proton.