Abstract
The beam spin asymmetry of the exclusive pseudoscalar channel e→p→e′p′η was measured for the first time in the deep-inelastic regime (W>2 GeV/c2 and Q2>1 GeV2/c2) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q2, xB, −t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sinϕ moments is a clear indication of a substantial contribution to the polarized cross-section from transversely polarized virtual photons. In the framework of generalized parton distributions (GPDs) this contribution is expressed via longitudinal-transverse interference between chiral-even and chiral-odd GPDs. The experimental results are compared to the existing theoretical models demonstrating the sensitivity to the product of chiral-odd and chiral-even GPDs and provide new constraints to the existing GPD parameterizations.
| Original language | English |
|---|---|
| Pages (from-to) | 426-431 |
| Number of pages | 6 |
| Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
| Volume | 789 |
| DOIs | |
| State | Published - 10 Feb 2019 |
Keywords
- Chiral-odd generalized parton distributions
- CLAS collaboration
- Deeply Virtual Meson Production
- Nucleon structure