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The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (e⃗ p→epγ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (xB from 0.11 to 0.58, Q2 from 1 to 4.8  GeV2, −t from 0.09 to 1.8  GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A~asinϕ/(1+ccosϕ). This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.


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Physical Review Letters

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F. X. Girod et al. [CLAS Collaboration], "Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries," Physical Review Letters 100.16 (2008) DOI: 10.1103/PhysRevLett.100.162002



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