OPT-IN: Differential cross sections and polarization observables from the CLAS Kâ photoproduction and search for new Nâ states

[Barry Ritchie]

An interesting and useful paper. I have a couple questions regarding the Legendre polynomial fit to the differential cross sections, though.

1. Total cross sections are presented, but we also know there are regions of phase space missing because CLAS can't completely cover those regions. Thus, some extrapolation is likely needed. Are the total cross sections provided in the paper derived from the coefficient on the zeroth term of the Legendre polynomial fit to the differential cross sections? While perhaps that is implicit, I still would suggest that point should be specifically mentioned in the run-up to Figure 6. Of course, if a different method was used to extract the total cross section, then that should be explicitly stated. 

2. Also, particularly given the discussion of the resonance search, what was the highest-order Legendre coefficient you used? I assume there was a statistical metric that truncated the number of terms for the fit, so perhaps a different cut-off was used for each set of differential cross sections, but it would still be useful to know how many terms were used (again, given the BnGa search). 

Again, this is a nice paper. Congratulations on reaching this stage.

Sincerely yours,

Barry