OPT-IN: The Beam-Target E asymmetry for vec gamma vec n -> pi- p in the Nâ resonance region

[David Ireland]

Dear Andy, et al.

Congratulations on getting this analysis to the submission stage. Looks like a nice set of results, which have the power to improve the theoretical models.

I have a couple of comments:
1. In our paper last year on KY observables, we provided Bonn-Gatchina bands for the calculations similar to what you have done with SAID, where in our case the bands indicated the spread in the event-weighted observable calculation. However, for the comparison between SAID and BnGa calculations to be meaningful they should either both be single lines or both bands. 

2. In para 1 of the RHS of page 3 you say "A weighted average of the results from the three analyses has been used as the best estimate of the $\pi^- p$ E asymmetries." I may have interpreted this incorrectly, but with three different analyses you can only compare them with each other to establish consistency. You must then pick one method for final results; using an average amounts to using the data three times over, which is not usually allowed in statistical analyses.

Best wishes,

Dave