Back to Search
Start Over
Beam-helicity asymmetry in photon and pion electroproduction in the Δ(1232)-resonance region at Q2 = 0.35(GeV/c)2
- Source :
- European Physical Journal A, European Physical Journal A, 2007, 32, pp.69-75. ⟨10.1140/epja/i2006-10277-3⟩, European Physical Journal A, EDP Sciences, 2007, 32, pp.69-75. ⟨10.1140/epja/i2006-10277-3⟩
- Publication Year :
- 2007
- Publisher :
- Springer Science and Business Media LLC, 2007.
-
Abstract
- The beam-helicity asymmetry has been measured simultaneously for the reactions (e p \to e p \gamma) and (e p \to e p \pi^0) in the $\Delta (1232)$ resonance region at $Q^2=$ 0.35 (GeV/c)$^2$. The experiment was performed at MAMI with a longitudinally polarized beam and an out-of-plane detection of the proton. The results are compared with calculations based on Dispersion Relations for virtual Compton scattering and with the MAID model for pion electroproduction. There is an overall good agreement between experiment and theoretical calculations. The remaining discrepancies may be ascribed to an imperfect parametrization of some $\gamma^{(*)} N \to \pi N$ multipoles, mainly contributing to the non-resonant background. The beam-helicity asymmetry in both channels ($\gamma$ and $\pi^0$) shows a good sensitivity to these multipoles and should allow future improvement in their parametrization.<br />Comment: 7 pages, 8 figures, version to appear in EPJA
- Subjects :
- Nuclear and High Energy Physics
Particle physics
Photon
Proton
media_common.quotation_subject
FOS: Physical sciences
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
01 natural sciences
7. Clean energy
Asymmetry
Resonance (particle physics)
High Energy Physics - Experiment
High Energy Physics - Experiment (hep-ex)
High Energy Physics - Phenomenology (hep-ph)
Pion
Dispersion relation
0103 physical sciences
[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
Nuclear Experiment
010306 general physics
media_common
Physics
010308 nuclear & particles physics
Compton scattering
Helicity
High Energy Physics - Phenomenology
[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]
Electromagnetic processes and properties
Elastic and Compton scattering
Meson production
Baryon resonances
Subjects
Details
- ISSN :
- 1434601X and 14346001
- Volume :
- 32
- Database :
- OpenAIRE
- Journal :
- The European Physical Journal A
- Accession number :
- edsair.doi.dedup.....55559aec4dcb92e56322870bbfe7f6dc
- Full Text :
- https://doi.org/10.1140/epja/i2006-10277-3