[Clascomment] OPT-IN:Multidimensional Measurements of Beam Single Spin Asymmetries in Semi-inclusive Deep-inelastic Charged Kaon Electroproduction off Protons in the Valence Region

[Sebastian Kuhn]

Nice paper - here are some comments:

1) While I understand the "wish for prestige" (PRL), I don't think it'll be easy to get the paper published there (not enough general interest, no "earth-shattering" results). With that in mind, I would prefer a somewhat more detailed explanation of the EXPERIMENTAL aspects, including Kaon PID (supported by figures), contamination, systematic uncertainties etc. in the MAIN text.

2) The discussion of the results is a bit at odds with what I can see in the figures. E.g., line 246-8 claim that "the ratio is rising or constant up to z = 0.4. For higher z it starts to fall rapidly in all bins." - I don't see this as a good description for all 9 bins shown. This claim is repeated in line 300-301. 

3) The Fig. 3-4 captions should explicitly state that the 3 rows correspond to the 3 different bins in x-Q2.