Deeply Virtual Compton Scattering at 12 GeV – E12-06-119

Deeply Virtual Compton Scattering at 12 GeV – E12-06-119

Qhard2 large t = Δ2

low -t process :

-t << Qhard2

Mueller, Ji, Radyushkin (94-96)

x + ξ x - ξ

P - Δ/2 P + Δ/2GPDs (x, ξ ,t)Mostly H for unpolarized proton target

Mostly H for polarized proton target~

The DVCS amplitude is expressed in terms of Compton Form Factors at LO:

(same for other GPDs)

The E12-06-119 proposal aims at measuring the Beam Spin and Target Spin Asymmetrieswith unprecedented accuracy over the wide CLAS12 kinematical range

using 80 (LH2) + 120 (polarized NH3) days of beam time

The E12-06-119 proposal aims at measuring the Beam Spin and Target Spin Asymmetrieswith unprecedented accuracy over the wide CLAS12 kinematical range

using 80 (LH2) + 120 (polarized NH3) days of beam time

Beam Spin Asymmetry

From 1% statistical error on extracted Twist-2 coefficient

to 10% statistical errorat high xB

IC in standard position – 80 days – 10^35 Lum – VGG model

Target Spin Asymmetry

IC in standard position – 120 days – 2x10^35 Lum – VGG model

Global fits by H. Moutarde, H only (PRD79, 094021 (2009)) CLAS12 pseudo data, 80 days of beam time

Global fits by H. Moutarde, H only (PRD79, 094021 (2009)) CLAS12 pseudo data, 80 days of beam time

Extracted Compton Form Factor – From 6 to 12 GeV

Projected results

Building a profile of the nucleon at different xB