OPT-IN:Extraction of A^sin(Ï)_LU moments from the hard exclusive Ï^+ channel off the unpolarized hydrogen target in a wide range of kinematics

[Mikhail Osipenko]

Dear Authors of pi+n BSA paper,

I have one question:

1) I believe that cos(phi) and cos(2*phi) moments in pi+n were published by CLAS already, how those published numbers compare to the values you get from 3-parameter fit using Eq.3? Do they agree point-by-point in entire kinematics? Is deviation below your systematic error?

2) why the BSA shall go to zero at t_min and t_max endpoints?

3) the "approximate Bjorken scaling" claimed in page 5 confuses me a little, do I remember well that the studied BSA has no leading twist term? If this is correct I would suggest to change your statement. Perhaps, the observed flat behavior is due to varying x-domain of integration (as well as t-range) which compensates the expected 60% change of asymmetry (~sqrt(Q2)).
In the backward region instead the result is compatible with sqrt(Q2) behavior, but errors are large.

4) the sign change around 90 deg. in CM is very intriguing, I hope you excluded all possible mistakes, like sign change in Lorentz boost etc. I just observe that the last point before the sign change at t=-2.5 GeV^2 and the first negative point at t=-3.4 GeV^2 agree in magnitude... have you tried to extract the BSA in this interval in smaller bins to see the transition (even with big errors).

Best Regards,
                  Mikhail.