OPT-IN:Target and Double Spin Asymmetries of Deeply Virtual Ï0 Production with a Longitudinally Polarized Proton Target and CLAS

[Michel Garçon]

Overall, the article reads well and the message is clear. Nice work ! I have some detailed remarks and corrections though:
Abstract l. 9 : Large VALUES, not amplitudes. The word amplitude is rightly used at the end of the same sentence.
l. 32: Insert  after “processes.” The sentence 
“The conventional ETbar = 2HTtilde+ET will be used as well hereafter. These GPDs can be accessed….” 
with optional reference to M. Burkardt, PRD 72, 094020 (2005). 
Eq. 1: F depends on Q2 as well (evolution)
l. 76: if I am not mistaken, eqs 2 and 3 are quite general, model independent. They only suppose one photon exchange. Then bar “at the leading twist”. Same applies to l. 243.
l. 82: unpolarized structure functions. Bar “spin”.
l. 93: [12] only deals with chiral even GPDs and DVCS. It is not the best place to introduce the GGL model  in this context. I would just use ref [17]. Same remark for caption of Fig. 4.
l. 136: “emitted” instead of “scattered” photons.
l. 147: “additional” instead of “extra”
Fig.1 x-label and line 156: use the same notation for missing mass.
l. 184 “polarization dependent” instead of “asymmetrical”
l. 198: “corresponding beam charge” instead of “total charge”
l. 206: [15] is not enough to calculate the ep spin asymmetry. It gives the formula, but you need a form factor parameterization to get a number. You should quote also the form factor parameterization which you used.
l. 209: remove \simeq .
l. 215: “were modified from 3sigma to 2.5…..”
l. 218: I’d rather see a range quoted here: “The corresponding variations of asymmetries ranged from ?? to ??% in all kinematical bins”. The average in l. 225, including all sources of bin to bin syst. errors, is fine there.
l. 249: full stop after “asymmetries” and then “This observable is important…”
l. 276: GGL
l. 293-295:  3 articles missing. the target spin asymmetry….the beam beam asymmetry… A more….
l. 307: “real part of the even-odd product …” instead of “real part of chiral-even and chiral-odd GPDs product…” since the quantities in brackets are not the GPDs themselves.
l. 308: The overall…
Ref [17]: the second author is J. O. Gonzales Hernandez (hence the GGL).