Speaker
Description
Generalized Parton Distributions are studied in exclusive reactions
like Deeply Virtual Compton Scattering (DVCS). In 2016 and 2017
DVCS was measured at COMPASS using 160 GeV positively and negatively
charged polarized muon beams provided by the M2 beamline of the SPS at CERN and
which was scattered off a 2.5 m long liquid hydrogen target. To perform an
exclusive measurement the target
was surrounded by a barrel-shaped time-of-flight system to detect
the recoiling target protons. The scattered muons and the produced real
photons were detected by the COMPASS spectrometer, which was supplemented by an additional electromagnetic calorimeter for the detection of large-angle photons.
The DVCS cross section is extracted separately for each beam charge and polarization to calculate the so called charge-spin cross section sum. Its dependence on the squared four-momentum transfer to the proton
is related to the transverse extension of partons in the proton covering the Bjorken $x$ domain of sea quarks. The talk will present the analysis method and preliminary
results of the 2016 run.
| Submitted on behalf of a Collaboration? | Yes |
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