[Clascomment] OPT-IN: Coherent photoproduction of pi+ from 3He

[Marco Mirazita]

page 3 end of section II
You should move the definition of Q^2 from page 8 to here

page 5 fig. 6 and page 6 fig. 9
You should extend the distributions of MM_t^2 to some negative value to fully show the peak of the missing pion

page 7 last row before eq. (2)
The target lenght here cannot be 155 cm.

page 7 and 8, systematic uncertainties 
You estimated the CLAS acceptance systematic uncertainty by looking at the sector-by-sector difference in the cross section, but what if there is some additional overall systematic uncertainty, common to all the 6 sectors?
Also, you take as systematic uncertainty the mean values of the sector-by-sector difference and the RMS of the differences due to different selection cuts. Why? I\'m afraid that taking the RMS you just double count the statistic error. You can check this by looking at the distribution of the difference divided by the nominal result, if statistical fluctuations are the main contribution you should see a gaussian with mean zero and sigma one.

page 8, section IV.A.
I\'m not sure about the shift of the main peak of the cross section with increasing energy, because the limited forward acceptance doesn\'t allow the full measurement of the peak.