CERN Accelerating science

Theses
Title	Proton structure studies using hard exclusive processes at COMPASS experiment
Author(s)	Pešková, Markéta (Charles U.)
Publication	2024 - 199.
Thesis note	PhD : Charles U., Prague (main) : 2024
Thesis supervisor(s)	Matoušek, Jan
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN SPS ; NA58
Keywords	Hadron structure ; COMPASS experiment ; SPS CERN ; Generalised parton distribution ; exclusive pi0 production
Abstract	The exclusive processes, such as hard exclusive meson production (HEMP) and deeply virtual Compton scattering (DVCS) are an excellent tool for studying generalised parton distributions (GPD). GPDs provide a novel and relatively unexplored view into the structure of nucleon and expand the knowledge given from parton distribution functions (PDF) and parton densities to a more com- plex, three-dimensional picture. While the golden channel of GPD parametri- sation is DVCS, the exclusive meson production gives access to complementary GPDs, provides information of flavour dependence of GPDs, and in case of exclusive π0 production in particular, also represents the main background pro- cess of DVCS, hence it is essential to constrain it. The theoretical formalism of GPD and HEMP description is outlined in the first part of the thesis. The mea- surement of exclusive processes represents an important part of COMPASS-II programme. The dedicated GPD programme commenced with a 4-weeks-long pilot run in 2012, followed by the main data taking in 2016-2017, using 160 GeV/c muon beams and a liquid hydrogen target, equipped with a recoil pro- ton detector. The COMPASS spectrometre and its configuration for the GPD programme is described in the second section. The exclusive processes require a perfect performance of...

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