eg1-dvcs

Spokesperson

A. Kim

Year

2009

Abstract

The target and double spin asymmetries of the exclusive pseudoscalar channel ep → epπ 0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2 , xB , −t and φ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs HT and ET , and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and ET . These data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.

Publication

1. A. Kim et al. (CLAS Collaboration) Target and Double Spin Asymmetries of Deeply Virtual π0 Production with a Longitudinally Polarized Proton Target and CLAS // arXiv:1511.03338, submitted to Phys. Lett. B (2016)

Quantities

A_UL   A_LL   A_LL^const   A_UL^sin φ   A_UL^sin 2φ   A_LL^cos φ

Measurements