Measurement of ep -> ep pi(0) beam spin asymmetries above the resonance region
The beam spin asymmetry (BSA) in the exclusive reaction ep -> epπ 0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The XB,Q 2 ,t, and O dependences of the π° BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin if) 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 nonzero 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.