[Clascomment] OPT-IN: Photoproduction of pi0 on Hydrogen using e+e-(gamma) detection mode with CLAS

[Sebastian Kuhn]

A few comments:
1) Abstract line 6: "where as" -> "whereas"
2) Abstract: I'm not sure what you are trying to say with "...quadrupled the world bremsstrahlung database..." - does "bremsstrahlung" refer to the initial photons? In that case I would just call it the photo production database or some such. On the other hand, neither the unobserved photon nor the e+e- should be referred to as "bremsstrahlung" (=braking radiation).
3) Fig. 1 and surrounding discussion confuses me: Is "M_E(pe+e-)" the MISSING energy (then why not "E_X") or the INVARIANT mass? Also, if I understand correctly, you are cutting out events with this quantity being LESS than 75 MeV - so you should call it (e.g. in the caption) the "M_E(pe+e-) > 75 MeV condition". If I'm wrong, it just shows that this explanation needs to be made clearer.
4) I may have missed it, but I didn't find an explanation how you go from (gamma,e+,e-) yield to pi0 cross section. In particular, you don't explain where the e+e- comes from and how you can extrapolate from that particular final state to the overall pi0 production cross section.
5) The caption for Fig. 3 has a non-syntactically complete sentence starting with "While"