# Measurement of ep->ep $\pi^0$ beam spin asymmetries above the resonance region

Abstract : The beam spin asymmetry (BSA) in the exclusive reaction ep->ep pi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer(CLAS). The xB, Q2, t and phi dependences of the pi0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin(phi) function and their amplitudes are extracted. Overall, they are of the order of 0.04 - 0.11 and roughly independent of t. This is the signature of a non-zero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00192985
Contributor : Dominique Girod <>
Submitted on : Friday, November 30, 2007 - 10:44:32 AM
Last modification on : Thursday, November 19, 2020 - 12:58:54 PM

### Citation

R. de Masi, M. Garcon, B. Zhao, M.J. Amaryan, P. Ambrozewicz, et al.. Measurement of ep->ep $\pi^0$ beam spin asymmetries above the resonance region. Physical Review C, American Physical Society, 2008, 77, pp.042201. ⟨10.1103/PhysRevC.77.042201⟩. ⟨in2p3-00192985⟩

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