Target and Double Spin Asymmetries of Deeply Virtual ${\pi }^0$ Production with a Longitudinally Polarized Proton Target and CLAS

Abstract

The target and double spin asymmetries of the exclusive pseudoscalar channel $\vec{e}\vec{p}\to ep{\pi }^0$ 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 $Q^2$, $x_B$, $-t$ and $\varphi$. 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 ${\tilde{H}}_T$ and $E_T$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $H_T$ and ${\bar{E}}_T$. These data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.

References in corpus (8)

• Nucleon Electromagnetic Form Factors
• Transverse spin structure of the nucleon from lattice QCD simulations
• Nucleon Tensor Charge from Exclusive ${\pi }^o$ Electroproduction
• Measurement of Exclusive ${\pi }^0$ Electroproduction Structure Functions and their Relationship to Transversity GPDs
• Rosenbluth separation of the ${\pi }^0$ electroproduction cross section
• Exclusive ${\pi }^0$ electroproduction at $W>2$ GeV with CLAS
• Hard exclusive pion leptoproduction
• The Boer-Mulders Function: Models and Universality

Cited by in corpus (8)

• Electron-Ion Collider in China
• The Spin Structure of the Nucleon
• Selected Science Opportunities for the EicC
• Measurement of the cross section for hard exclusive ${\pi }^0$ leptoproduction
• Extraction of beam-spin asymmetries from the hard exclusive ${\pi }^{+}$ channel off protons in a wide range of kinematics
• Deep exclusive electroproduction of ${\pi }^0$ at high $Q^2$ in the quark valence regime
• Semi-Inclusive ${\pi }_0$ target and beam-target asymmetries from 6 GeV electron scattering with CLAS
• Wide-angle photo- and electroproduction of pions to twist-3 accuracy