We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q(2). The helicity-independent cross section is also measured at Q(2)=2.3 GeV(2). We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.

Camacho, C Muñoz

Camsonne, A

Mazouz, M

Ferdi, C

Gavalian, G

Kuchina, E

Amarian, M

Aniol, KA

Beaumel, M

Benaoum, H

Bertin, P

Brossard, M

Chen, J-P

Chudakov, E

Craver, B

Cusanno, F

de Jager, CW

Deur, A

Feuerbach, R

Fieschi, J-M

Frullani, S

Garçon, M

Garibaldi, F

Gayou, O

Gilman, R

Gomez, J

Gueye, P

Guichon, PAM

Guillon, B

Hansen, O

Hayes, D

Higinbotham, D

Holmstrom, T

Hyde-Wright, CE

Ibrahim, H

Igarashi, R

Jiang, X

Jo, HS

Kaufman, LJ

Kelleher, A

Kolarkar, A

Kumbartzki, G

Laveissière, G

Lerose, JJ

Lindgren, R

Liyanage, N

Lu, H-J

Margaziotis, DJ

Meziani, Z-E

McCormick, K

Michaels, R

Michel, B

Moffit, B

Monaghan, P

Nanda, S

Nelyubin, V

Potokar, M

Qiang, Y

Ransome, RD

Réal, J-S

Reitz, B

Roblin, Y

Roche, J

Sabatié, F

Saha, A

Sirca, S

Slifer, Karl

Solvignon, P

Subedi, R

Sulkosky, V

Ulmer, PE

Voutier, E

Wang, K

Weinstein, LB

Wojtsekhowski, B

Zheng, X

Zhu, L

Jefferson Lab Hall A Collaboration

published 

December 31, 2006

General Physics

Physical Review Letters  Journal