Target and double spin asymmetries of deeply virtual π 0 production with a longitudinally polarized proton target and CLAS
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 $$\phi$$. 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 $$\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); George Washington Univ., Washington, DC (United States); Mississippi State Univ., Mississippi State, MS (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- Contributing Organization:
- CLAS Collaboration
- Grant/Contract Number:
- SC0016583; FG02-07ER41528; AC05-06OR23177
- OSTI ID:
- 1344582
- Alternate ID(s):
- OSTI ID: 1351109; OSTI ID: 1439852
- Report Number(s):
- JLAB-PHY-17-2440; DOE/OR/23177-4111; arXiv:1511.03338; S037026931730134X; PII: S037026931730134X
- Journal Information:
- Physics Letters. B, Journal Name: Physics Letters. B Vol. 768 Journal Issue: C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
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