Leif Jönsson
Professor emeritus
Deeply virtual Compton scattering and its beam charge asymmetry in e(+/-)p collisions at HERA
Author
Summary, in English
A measurement of elastic deeply virtual Compton scattering gamma*p --> gamma p using e(+) p and e(-) p collision data recorded with the HI detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb(-1), almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q(2) of the exchanged photon and the centre-of-mass energy W of the gamma*p system in the kinematic domain 6.5 < Q(2) < 80 GeV2, 30 < W < 140 GeV and |t| < 1 GeV2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q(2) and W values and exponential t-slope parameters are derived. Using e(+) p and e(-) p data samples, a beam charge asymmetry is extracted for the first time in the low Biorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe-Heitler and deeply virtual Compton scattering processes. Experimental results are discussed in the context of two different models, one based on generalised parton distributions and one based on the dipole approach. (C) 2009 Elsevier B.V. All rights reserved.
Department/s
- Particle and nuclear physics
Publishing year
2009
Language
English
Pages
391-399
Publication/Series
Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume
681
Issue
5
Document type
Journal article
Publisher
Elsevier
Topic
- Subatomic Physics
Status
Published
ISBN/ISSN/Other
- ISSN: 0370-2693