[Clascomment] OPT-IN:Longitudinal target-spin asymmetries for deeply virtual Compton scattering

[Michel Garçon]

Note added concering the relative contributions of H_tilde and H to AUL:

at leading-twist, they are in the ratio
F1*H_tilde :: (xB/(2-xB))(F1+F2)H

In the factorized ansatz (just for an order of magnitude):
H_tilde = delta_q(x) * gA(t)
H       = q(x)       * (F1+F2)

At t = 0, F1 = 1, F2 = mu_p -1 = 2.8 -1, gA = 1.3

Then the contributions are in the ratio
(2/xB) * (Delta_q/q) * (gA/mu_p) ~ (5-10) * 1/4 * 1/2 ~ 1

So the contributions are comparable. This will probably be confirmed by VGG.

Cheers,
Michel.