[Clascomment] OPT-IN: Exclusive pi-0 electroproduction at W > 2 GeV with CLAS

[Jean-Marc Laget]

Dear Paul, Valery, Ivan and Silvia,

I read the draft paper on pi_zero electro-production. It is well balanced and provides a fair discussion/presentation of the available physical interpretations available on the market (besides, of course, the description of the experimental method and the data reduction procedure).

I have a few comments/ corrections on the way the Regge model is presented:

I- Reference [30] is misplaced. It is a general review that describes the state of the art in the seventies'. On page 19 and Figure 20, only the results of ref. [20] are discussed and presented. So I suggest to move ref. [30] from page 19 and Fig. 20 to the introduction page 3, column 1, paragraph 2, line 6:

"....insights into the nature of hadrons and their interactions [30]."

2- Page 19, Column 1, paragraph 2, line 7: replace "fits" by "predictions". If I had performed a fit the agreement would have been perfect!!

3- Page 19, column 1, paragraph 1, line 1: "rho_minus-p" should be written "rho_zero-p"

4- Page 15, column 2, paragraph 1 (A-Regge model), rephrase the first sentence:

The Regge model with charge exchange and pi+- final state interactions ",besides pole terms and elastic pi_zero rescattering," had been successfully.....

It is the interplay between  the pole terms and the elastic and charge exchange FSI that allows to obtain a good representation of the Desy data.

5- The Regge predictions have already been compared to beam and target asymmetries (Figures 11 and 12 in ref.[20])

6- Conclusion, page 20, column 2, paragraph 2, line 4, add:

....rescattering "amplitudes" (Fig. 22) to the original "pole terms and" pseudoscalar rescattering "amplitudes"...