[Clascomment] OPT-IN:Precision measurement of g1 of the proton and the deuteron with 6 GeV electrons

[Michel Garçon]

Here are some comments on the g1 paper from eg1-dvcs data (Yelena et al.) :
•	Abstract:
-	Is the mention “2.5 % r.l.” necessary/useful here? If yes, do not use this abbreviation in the abstract.
-	“lab” -> “laboratory”
-	“For DIS kinematics” -> “For usual DIS kinematics”, in order not to be in contradiction with the following sentence.
•	Intro:
-	1st sentence: “including…in particular” -> “including in particular…”
-	RHIC-spin: is it not pi0 production, and not photon production? Also there are three underlying partonic processes: qq, qg, gg, and all three enter the analysis to extract Delta_G.
•	II-A: “a more careful treatment” -> “an improved treatment”
•	“gm” -> “g”
•	Just before Fig.1: azimuthal -> polar
•	Fig.1: use an event display relevant to this experiment and paper: add solenoid, IC, upstream target, and put only one in-bending track.
•	P.5: the 0.12 GeV offset is not explained, understood, here.
•	Fig.6: NH2, ND2 !!
•	P.12: y not defined here, but 2 pages later.
•	Fig. 9-12: somewhere the choice of binning in W and in x should be discussed, since there are many more bins in W than in x.
•	Eq. 27: since gamma is not used anywhere else, why not replacing gamma^2 with 1/tau ?
•	Conclusion: would you be comfortable with suggesting a cut at 2.35, instead of 2.4 (which cuts a lot of the data !).
•	Tables of results: why not used CLAS data base and refer to it ?.
Best regards, 
Michel Garçon