[Clas_cascades] Comments to normalization note

[Elton Smith]

Dear Lewis,

Here are some comments to your normalization note:

page 1. abstract

The abstract could be made crisper, but can wait till the document is
complete to revisit.

page 1 introduction

The introduction should add a brief description of the g11 data set (new
cross section analysis) and motivation for selection of this cross section
over others. Some of the material for this is contained in Section 3.1
(Kinematic binning). But this discussion should back up the entire document.

page 1 introduction last paragraph

It states that the only cut on the data is the neutron missing mass.
However, the basis for the data is a skimmed set for two pions (some
description of this is in Section 3.2. Therefore, many selection cuts were
made before the analysis stage. Therefore the skimmed data set should be
described early on. I would suggest to move the last paragraph from the
introduction into Section 2 (Experiment), perhaps adding a new section 2.2
Data selection (and/or reduction).

page 1 Sec 2.1 first paragraph

There should be a reference to Exp 04-010 (or equivalent eg3).

page 2 Sec 3.1 last paragraph, suggestion

"The acceptance-corrected yields were computed by weighing individual events
with the inverse of the acceptance.

page 2 Sec 3.2 second sentence, unclear

What about the pi-?

p. 4 first sentence, clarify terms

The three particle vertex time must be described. Is it the average of the
three particle's tof time extrapolated back to the vertex?

The TOF difference of photon and average particle time of 2 ns. Is this the
difference between the photon time at the target relative to the average of
the three particle's TOF times extrapolated back to the vertex?

p 4 Figure 2,

Can you make comparable plots for eg3 and g11? eg. neutron MM for both?

p. 5 Sec 4.2, I believe instead of uncertainties you probably mean shifts?

"...still exist systematic SHIFTS in the particle momentum determined from
CLAS using the standard reconstruction software. These SHIFTS are likely due
to the residual effect of imperfect knowledge of the magnetic field. These
SHIFTS can lead to CHANGES in the masses...."

p. 5 Sec 4.3, paragraph, questions, suggestions

What are proper cuts?

Add reference to GSIM.

Next to last sentence suggestion: "The fiducial volume cuts are a function
of the momentum and the charge of the particle only since the curvature...of
the field. (the torus was run at a constant field throughout eg3).

p. 6 Sec. 4.4, first sentence

What is p+ ? should this be p pi+ mass bin?

p. 6 Sec. 4.4 second sentence, suggestion

The yields were extracted from fits to the one-dimensional histograms of the
p pi+ mass.

p. 6 Sec 4.4, replace sentence starting with "For all. the energy bins..."

Replace with "The fitting ranges were adjusted for each energy bin in order
to properly fit the background under the peak with a 3rd order polynomial."

p. 6 bottom paragraph, first sentence:

To check the systematics of this fitting procedure, we also performed...

p. 7 first paragraph, unclear

I'm not sure what you mean by "this procedure was too crude..."

p. 7 second paragraph, I believe you want to say something like

"The fitted range was chosen to be able to accurately reproduce the
background shape under the peak without developing a full description of the
p pi+ mass to very high masses...."

p. 8 second paragraph

How many events were generated for each t-slope?

Do you have a plot that confirms that your choice of t=4 is valid?

p. 7 last sentence before Fig 5, suggestion:

"The acceptance was obtained by passing the simulated events through the
same reconstruction program used for experimental data, in comparison to the
number generated.

p. 7 bottom sentence, description of Fig. 5 does not agree with the caption.

p. 8 top sentence, ditto for caption of Fig. 6

p.8 middle second sentence, reword "All these parameters..."

"All these corrections(?) were applied to the data in order to achieve
maximum acceptance for the selection cuts which were applied as part of the
two-pion skim program....

p. 8 third paragraph,

timing cut between three final state particles.. The timing cut is
presumably applied to the difference between the vertex times of the
particles.

Cuts also applied to the difference between EACH particle vertex time and
the tagger ?

p. 10 Fig 7 Absolute values on the left plot?

p. 10 first sentence. Missing figure number 7?

A description is needed for Fig 8 and 9?

p. 10 second paragraph, last sentence, suggestion (and is this true?)

We required the proton p<450 MeV, which the simulation shows did not
eliminate any good events.

p. 13 Fig 10 caption, lacking note on yield

Ratio of g11 data seems to have a binning problem. About every 3rd point
seems to be high...?

p. 14 second line, spelling

p. 14 fig 11. Should note that this is for simulated data. How is it
different from Fig 5?

p. 15 Sec 4.6 first sentence, suggestion

"In order to determine the cross section, the data must be normalized to the
measured photon flux..."

General: Discussion of trigger efficiencies should be in Sectin 4 (not 5).

p. 16 second paragraph, move to a trigger inefficiency correction section.

Call this section untagged energy range correction.

Merge second paragrapn with the content of Section 5.2 into a new section
on trigger inefficiency, as distinct from untriggered range correction.

p. 18, first paragraph. (also note two periods typo)

Need to describe how 14 was created, i.e. with the rate for Lambda
production.

p. 19 Table 1, rows 2 and 3

Use one line per event selection, instead of combining two into one.

p. 19 Table 1, third row

What are the double <<?

p. 20, Fig 16. Need to make a comment/explanation for the dip in the
second bin of the Delta cross section.

p. 21, Section 5.2 move to new Section 4.8

p. 25, immediately before Section 5.3

Sentence says that the g11 efficiency map is described in the next
section, but I don't find it. Also, I suggest that all trigger efficiency
discussions be made in Section 4, before the actual cross sections are
discussed.

p. 26, top paragraphs

The discussion the paragraphs do not match the caption (or figure) in Fig.
21

p. 27, top, figure cuts off text.

Note that you can use the bounding box in the includegraphics latex
instruction to limit range of figure

p. 27 bottom paragraph, more explanations needed.

Explain the reasons for choosing the photon energy limits of 2 to 5 GeV.

Describe what the average fit is.

p. 29 Fig 24.

Either describe differences between top and bottom plots in figure in the
caption. Alternatively, it might be better to have a single plot which
shows the two data averages at the same time.

p. 29

Need a stronger conclusion for the summary, in particular should give the
estimated systematic uncertainty in the normalization based on this work.
For example that the comparison of the Delta++ production agrees with
world data (SAPHIR) and g11 within 8%(?).


Elton Smith
206 Pageland Dr.
Yorktown, VA 23693
(757) 867-8790