[Clascomment] OPT-IN: Measurement of two-photon exchange effect by comparing elastic e± p cross sections

[Stepan Stepanyan]

Brian,

Thanks for the reply and taking into account my comments. I agree
if you can go by without Fig. 10 you should do it, otherwise in the
paper it is better to have a proper fit. As for Fig. 18, I do not have
strong feeling, if you think it is clear as is or some clarifying words
are needed, I am fine with that.

Regards, Stepan

On 2/17/16 5:23 PM, Brian Raue wrote:
> Stepan,
> Thanks for your feedback.  Answers below.
>
> Brian
> ________________________________________
> From: Stepan Stepanyan <stepanya at jlab.org>
> Sent: Monday, February 15, 2016 11:33 AM
> To: clasmbr at jlab.org; clascomment at jlab.org; brooksw at jlab.org; Brian Raue; weinstei at jlab.org; mikewood at jlab.org; johna at anl.gov; fersch at jlab.org; akalh001 at odu.edu; contalbrigo at fe.infn.it; drima001 at fiu.edu
> Subject: OPT-IN:    Measurement of two-photon exchange effect by comparing elastic e± p cross sections
>
> line 260 - should be "... toroidal magnetic FIELD …"
> fixed
>
> line 316 - is "a" needed before "TPE collimator"?
> probably should be "the"
>
> line 343 - should it be "... to each OTHER …"?
> fixed
>
> line 391 - "d" is missing, should be "distribution"
> previously fixed
>
> Fig. 10 - fit looks really ugly, the peak position of the red histogram is shifted left compare to
> Gaussian function. The correct way os to fit with some background function or limit upper edge
> of the fit to lower W.
> Yes, it is not a great fit but it isn't intended to be.  We aren't pulling yields out of the fit but simply showing that after corrections the proton peak is about where it is expected to be.  A fit with a reasonable background would have shifted the Gaussian peak to slightly lower values. We have previously shown (in analysis reviews) that our analysis is pretty insensitive to momentum corrections.  Perhaps the figure isn't even necessary and even raises irrelevant  issues.  If my collaborators agree I will cut it and adjust wording accordingly.
>
> line 567 - how you deal with non-gaussian form of E- for +/- 3\sigma cut
> Fig. 18 of E- for low eps and high Q^2 shows that the background is pretty big but that the signal is pretty much Gaussian.  The non-Gaussian-ness of the distribution in Fig. 12 is because we are summing over all kinematics and the widths of the distributions and the level of background are kinematic dependent. The 3-sigma cut is also kinematic dependent.   Should I put a sentence in the caption to clarify?
>
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