[Clascomment] OPT-IN: Measurement of the Sigma Pi Photoproduction Line Shapes Near the Lambda(1405)

[Reinhard Schumacher]

Hello Elton,

	Thank you for your comments on the paper.  We have taken them into 
account as we create the final version of the paper.  It should be ready 
in a few days.

Cheers,
Reinhard

___________________________________________________________________
Reinhard Schumacher         Department of Physics, 5000 Forbes Ave.
Carnegie Mellon University, Pittsburgh, PA 15213, U.S.A.
phone: 412-268-5177         web: www-meg.phys.cmu.edu/~schumach
___________________________________________________________________

On 01/07/2013 05:42 PM, Elton Smith wrote:
> Hi Kei and Reinhard,
>
> This is a very interesting paper and well written. I do have a few comments/suggestions:
>
> p. 6, Eq. 2. the variable m_calc is a poor choice, since the mass is not calculated, but assumed (just use m?). Also the units in Eq 2 do not match due to the "c" in the numerator. Either add more c's in the square root or drop.
DONE.

>

> p. 8 Fig 4 caption, third line.
> You should be clear that the pi- and pi- and pi+ are additional particles in the event (i.e. other than the K+ plotted in the figure. For example, "... rejection cut; after requiring an additional negative particle identified as a pi- as shown in Fig 3; and after requiring two additional tracks identified as pi- and pi+..."
DONE.
>
> p. 12, line 195. I seem to recall that the trigger inefficiency for g11 was on the order of 15%, but can't seem to find a reference. Is my memory failing?
You are remembering the issue with the "extra" deadtime correction. 
That was about 15%.  Here we are talking about something else.
>
>
> p. 16, line 259 "only relative heights" ->  normalization?
DONE.

>
> p. 16, line 269-275. This is a very important paragraph. I have a few questions/suggestions
> I assume that the subtraction of the contributions from the S(1385), L(1520), K* were all assuming incoherent sums.
You should probably state this explicitly.
DONE.
To what extent can this assumption weaken your argument (later in the 
paper) that the effects of these states have been eliminated?
This is addressed in Section VII.B on K* removal.  We studied this a lot.

> line 271-272. "...we apply to it the acceptance correction." ->  "to obtain the true line shape, we divide the residual distribution by the acceptance based on the Monte Carlo simulation...."
various things changed in this area.
>
> p. 17 Fig 15. and paragraph 276-285.
> It is stated that the total fit is "now close to the actual data, and we see how the iteration of templates converted to stable line shapes..." While it visually appears that the fits in Fig (a) are somewhat worse than those in Fig (b) in the region around 1400, it might be good to give some quantitative estimates of this, e.g. chi2/dof. Of course many distributions have been obtained this way, so you might be able to give average improvements in chi2 for a given number of degrees of freedom. The chi2 also gives the reader a quantitative number for the agreement of the fits to the data.
It is hard and probably not helpful to summarize this with a single 
number.  We actually deal with this at some length by introducing the 
point-to-point systematic estimates that are stated in the (previous 
version) lines 339+ and shown in Fig. 17.
>
> p. 19 fig 16. Two comments/questions
> Comment: the contrast of colors is poor. The change from light magenta to red is invisible.
We've not found a great alternative for this.  The point is that the 
data lie close together, hence by construction hard to tell apart.
> Question on the systematic estimates. They do not seem quite consistent with the figure. Look at (b), for M=1.41 GeV. This is the largest difference between magenta and blue, but the histogram looks almost constant in that region. Am I missing something?
The histogram is a 3-bin average, which easy to spot in several places 
where there is an isolated discrepant pair.  We added a word to alert 
the reader about this.
>
> p 21 line 350 "....whatever coherent admixture OF ISOSPIN STATES is working..."
DONE.

>
> Figs 17, 18, question. How are the BW curves normalized? Do the models predict an absolute cross section? If not, you could add the normalization assumption in the caption(s).
Fixed caption for Fig 17; Fig 18 is discussed in the text.
>
> p. 30 lines 542-561. You may wish to have a single paragraph and preface the sentence in 546 with "We remind the reader that our fit..."
Fixed.
>
> p. 33 line 569, suggestion: "...contribution also APPEARS TO BE REQUIRED."
Changed.
>
> P. 34. Conclusions ->  Summary and Outlook?
> You may wish to go over this critical section carefully. For example
> line 619 "...some sigantureS OF a two-pole picture..."
DONE.

> line 620 last word complication ->  complexity?
DONE.

> line 621 "....the choice OF  a one..."
> Interchange paragraphs 624-626 with last one?
No, we want the final message to be strong.

> line 628 "The present work has, HOWEVER, provided..."
Changed.
>