[Clascomment] OPT-IN: First CLAS12 measurement of DVCS beam-spin asymmetries in the extended valence region

[Sebastian Kuhn]

Greetings! Overall a very nice result and a nice paper. I have only one major concern: The section "Results" does not show much in terms of actual data and spends too much space (imho) on an explanation of ANN and reweighing. I would prefer a kinematic plot that shows all the bins in x and Q2 (and perhaps even t) for which we have new data, with older data kinematic coverage indicated. Fig. 4 does show that we improve the precision of our knowledge of CFFs in the region where we already measured with CLAS6, but maybe it could be "de-emphasized" relative to the large new kinematic coverage. Another option would be to increase Fig. 5 by showing the same x/Q2 bins, but for several t-bins (e.g., 3 rows with 3-4 plots each). I realize that the complete data will be in the Supplemental Material, but my preference is to show more of our data in the Results section.

Here are some minor comments (with line numbers):
16 - ...nucleon structure, including THE composition of [leave out "its"] spin and pressure distributions within [leave out "it"].
21 - ...and a change in the nucleon's momentum after reabsorption of the parton expressed in the Mandelstam variable t.
36 - ...leading order in PERTURBATIVE Quantum Chromodynamics (pQCD)..."
38 - In the experimentally indistinguishable Bethe-Heitler (BH) process, ..
47 - ... interference term BETWEEN THE AMPLITUDES FOR both processes.
50- remove "a", and at the beginning of line 51, "from it".
84 - Pavel Alekseyevich Cherenkov is Russian and not written with a Czech letter.
89 -: Seems a bit redundant with the previous sentences. Maybe instead: "Scattered electrons are detected in the forward part of CLAS12. About 80%..."
158ff: I am a bit confused by the discussion of pi0 contamination. In line 163 you quote sigma_pi = 10% - of what? (percentage must be relative to something). Is it the relative uncertainty on "f"? Shouldn't it then be "sigma_f"? In any case, Eq. 2 needs to be consistent with how you define these quantities. You might also want to FIRST state that the following is a discussion of systematic uncertainties, before you introduce sigma_pi.
Fig. 4: If you keep it this way, maybe the caption could be a bit clearer that only the ANNs are reweighed, not KM15. Maybe "...and PARTONS ANNs. The latter are shown both before and after..."

Other than that, full speed ahead.