Münster 2017 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 46: Hadron Structure and Spectroscopy VI
HK 46.1: Group Report
Thursday, March 30, 2017, 16:45–17:15, F 5
The t-dependence of the pure DVCS cross-section at COMPASS — Horst Fischer, Simon Gerstner, Matthias Gorzellik, Pirmin Hofmeier, •Philipp Jörg, Christopher Regali, and Tobias Szameitat — Albert-Ludwigs-Universität Freiburg
A major part of the COMPASS-II program will be dedicated to the investigation of Generalized Parton Distributions (GPDs), which aim for the most complete description of the partonic structure of the nucleon. GPDs are experimentally accessible via lepton-induced exclusive reactions, in particular the Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP). At COMPASS, those processes are investigated using a high intensity muon beam with a momentum of 160 GeV/c and a 2.5 m-long liquid hydrogen target. In order to optimize the selection of exclusive reactions at those energies, the target is surrounded by a new barrel-shaped time-of-flight system to detect the recoiling particles.
COMPASS-II covers the up to now unexplored xBj domain ranging from 0.01 to 0.15. From the sum of cross-sections measured with positive and negative beam polarities, the pure DVCS cross-section and its t-dependence can be extracted.
Pilot measurements for the COMPASS II program allow for an extraction of the t-dependence in a single xBj bin,
thus providing first information on the nucleon transverse size in an up to now uncharted xBj regime.
* Supported by BMBF and the DFG Research Training Group Programme 2044.