[Qweak_transverse_prl_comments] Fwd: [Q-weak] First draft of the Qweak elastic transverse asymmetry paper

[Buddhini Waidyawansa]

---------- Forwarded message ----------
From: Steven P. Wells <wells at phys.latech.edu>
Date: Mon, Sep 8, 2014 at 3:51 PM
Subject: Re: [Q-weak] First draft of the Qweak elastic transverse asymmetry
paper
To: Buddhini Waidyawansa <buddhini at jlab.org>



Hi Buddhini,

Thanks for circulating the draft. I really like the paper, especially
the tie in to the TPE correction to the MuSE observables. In the past,
the only motivation for B_n in connection with the TPE calculations was
either through dispersion corrections to relate the imaginary part to
the real part, or more generally to test the loop formalism in any
two boson Feynman diagram. That being said, I have a few
comments/corrections,
and I also found some grammar that could be cleaned up. So, here goes:

1) In referencing my general comment about the explicit tie in to the MuSE
corrections, is there room available in the paper to explicitly write down
the
TPE corrections to whatever MuSE measures, to show, like you did in your
pizza seminar, that the helicity flip amplitudes (I think I remember F_4
twidle,
F_5 twidle, and F_6 twidle) are only accessible through B_n, and not some
other observable.

2) In the paragraph which includes Eq. (1), your statement of
" . . . parity conserving, naively time reversal violating . . ." should be
replaced with
" . . . parity conserving, time reversal odd . . ."

3) In the paragraph starting "Approximately 54 hours of data . . .", the
second
sentence, "The 150 uA circularly polarized electron beam . . ." should be
replaced with
"The 150 uA longitudinally polarized electron beam . . ."

4) The paragraph starting "For the purpose of suppressing false asymmetry
contributions . . .", I think it would be more clear if you added "to the
parity violating measurement" after
" . . . suppressing false asymmetry contributions . ."

5) In Eq. (3), the standard unit vector normal to the scattering plane is
$\hat n$, and
$\hat k$ and $\hat k^{\prime}$ are used for the incoming and outgoing
electron directions.
So, I would replace $\hat k$ in Eq. (3) with $\hat n$, and define $\hat n$
in the text just
below that equation with

$$\hat n = {{\vec k \times \vec k^{\prime}}/over{\vert \vec k \times \vec
k^{prime} \vert}}$$

That's all I had for corrections and/or suggestions, but I did find some
grammar issues:

1) Paragraph 1, sentence 4, starting "This discrepancy was empirically
shown . . ."
change " . . .amplitude which modify . . ." to " . . . amplitude which
modifies . . ."

2) Paragraph 2, starting "Even though modern TPE . . .", Sentence 3
starting "However,
the recent disagreement . . ." drop the words "to be" at the end of that
sentence.

3) Paragraph 2, sentence 4 starting "Furthermore, the value of the magnetic
ratio . . ."
change ". . . agreement with one another and world average . . ." to
" . . . agreeement with one another and the world average . . ."

4) Paragraph 2, sentence 6 starting "One correction [19] . . ." change
" . . . accounts for a ~ 11% . . . " to " . . .accounts for approximately
an 11% correction . . ."

5) Paragraph 3, starting "A beam normal spin asymmetry . . .", sentence 2
starting
"It is a parity conserving . . .", replace "vanish" with "vanishes"

6) Paragraph 3, sentence 3 starting "The asymmetry is generated . . .",
replace
" . . . and have the form . . ." with " . . . and has the form . . ."

7) Paragraph 3, last sentence, replace " . . . are invariant amplitudes
which enters . . ."
with " . . . are invariant amplitudes which enter . . ."

8) Paragraph 4, first sentence, replace " . . . rely on Eq. (1) and
absorptive part . . ." with
" . . .rely on Eq. (1) and the absorptive part . . ."

9) Paragraph 5, sentence 2 starting "This measurement is part of . . .",
replace
" . . . to constrain the systematic contribution . . ." to " . . . to
constrain the systematic contributions . . ."

10) Paragraph 9, sentence 3 starting "The correction determined from . . ."
replace
" . . . for a aluminum background . . ." with " . . . for an aluminum
background . . ."

11) Paragraph 9, sentence 6 starting "In addition to these dominant . . .",
replace
" . . . was also studied . . ." with " . . . were also studied . . ."

12) Paragraph 12 starting "Above corrections are applied . . ." change that
to
"The above corrections are applied . . ."

OK, that's all I found. Good luck pushing this through, and I think it will
be a great
publication.

Best,
Steve

P.S. If you are still interested in giving a seminar here at LaTech, there
are plenty
of dates still open.



-- 
-------------------------------------------------------------------
Buddhini Waidyawansa
Postdoctoral Fellow
C122,
12000 Jefferson Ave,
Newport News, VA 23602.
TP 757-912-0410
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