<div dir="ltr"><br><div class="gmail_quote">---------- Forwarded message ----------<br>From: <b class="gmail_sendername">Greg Smith</b> <span dir="ltr"><<a href="mailto:smithg@jlab.org">smithg@jlab.org</a>></span><br>Date: Tue, Sep 16, 2014 at 5:10 PM<br>Subject: Re: [Q-weak] First draft of the Qweak elastic transverse asymmetry paper<br>To: Buddhini Waidyawansa <<a href="mailto:buddhini@jlab.org">buddhini@jlab.org</a>><br><br><br>
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Hi Buddhini,<br>
<br>
I have some comments... First though, congratulations! I was really
surprised how well written your paper was right out of the gate.
Excellent job! Thank you so much for doing this, for all of us. I
know better than most how much work it is to write a draft. Thank
you for all the hard work you put into this! I really enjoyed
reading it. <br>
<br>
After Adesh's thesis, I expected to find the word "the" either
missing or used when it should not be on every line of this paper,
like it was (almost) on every line of his thesis. Whew!<br>
<br>
I am a really picky critic. It's amplified by my unfamiliarity with
the subject of your paper, but the flip side of that is that that
makes me a great critic, one that's more representative of your
target readership. So some of my questions may be dumb. But if I
have them then so will most readers I reckon. SO please don't get
upset by my comments, which I put forward in the spirit of trying to
help make the paper better. Don't take them personally- that's 1000%
not what they should be misconstrued as. I just want to help, and I
think you did an outstanding job already. You said you only had a
few comments so far, and so I read your manuscript carefully in the
hopes that it will make the 2nd draft much closer to the final
draft! I'm saying all this because when I got comments on the Wien 0
PRL like what I'm sending you now, I wasn't happy for the most part.
I wanted my drafts to be perfect (they weren't!). I hope that's not
your reaction here. <br>
<br>
I'll pass you my marked-up paper copy now- it has things not
included below. It's also attached.<br>
<br>
In general, and even though I made the same mistake sending out the
draft of our commissioning PRL for comments, I think it would be
better to have a larger font (for us old guys), double spaced,
line-numbered version (as well as a companion version in the final
PRL format to check length, etc.) for editing drafts. It's almost
impossible to comment on a paper version of the draft you sent, it's
too closely spaced. And line numbers make your job easier as well as
the reviewers, something I learned during the NIM editing process!<br>
<br>
First: hyphens. I am hyphen-blind and was mercilessly slammed by
Katherine Myers over this often-ignored aspect of English grammar.
She must have pointed out at least 100 problems of this type in the
NIM paper. Google "hypenation rules" and you'll see what the rules
are, but also you'll see <a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.apastyle.org%2Flearn%2Ffaqs%2Fwhen-use-hyphen.aspx&ei=hzMXVLTvNteqyASK24L4Aw&usg=AFQjCNELOuFjf_5DQsf-TaDBoXjyXTl8Gg&bvm=bv.75097201,d.aWw" target="_blank">here</a>
that the rule is pretty slippery and it's hard to know when to use
it and when not to. In a nutshell, if there are 2 adjectives before
a noun, you hyphenate them unless it's common usage not to, but
especially when doing so helps improve the meaning even in the
slightest. In the abstract for example, I think "Beam-Normal" should
be hyphenated. "Electron-Proton" and "electron-nucleon" too in front
of the noun "Scattering". "helicity-flip" in front of "amplitudes".
But I don't know if "Single-Spin" should be hyphenated in front of
the noun "Asymmetry" or not (probably... ask Katherine). These
appear multiple times throughout the paper. And there will be many
more missing hyphens in other examples throughout the paper. I won't
elaborate further. <br>
<br>
OK- just spoke to you about this, and you suggested focusing mostly
on the big picture for this 1st draft. I am marking up a paper copy,
with difficulty, but here are some big picture comments:<br>
<br>
I don't think we have ever discussed this as a collaboration, or on
the council, but I wonder whether or not on some of the ancillary
papers where 1 or 2 individuals made outsized contributions, they
(you) should be 1st author. I like that you went alphabetical for
now. I think we should definitely keep that for the main Qweak
papers, where so many individuals contributed. But for this one, as
well as others that may come down the pipe, I wouldn't object to
putting your name 1st (on this one), and then going alphabetical
after your name. We'll have to discuss it- it's a bit of a hot
potato topic I guess. I'll try to remember to bring it up (better I
do, or someone else does, than you). <br>
<br>
In the middle of the 1st column, page 2, you say both that there is
"recent disagreement" and "good agreement" between the Rosenbluth
and pol. xfer methods. You can't have it both ways. <br>
<br>
At the end of the 1st column, page 2, it gets very confusing. You
refer to the well-known 7.7 sigma p-rad problem. Then an 11%
correction. Then a 1% effect on the correction. I can't tell what
the percentages are percentages of. You have to lay out this
landscape in a single language, not 3 different ones. How much of
the 7.7 sigma problem is the proton polarizability term, and how
much of that is up for grabs due to the uncertainty in the TPE
corrections? If it's 1% of an 11% correction that in turn is only a
small part of the 7.7 sigma discrepancy, then I don't see how this
is relevant, in practice. If it's a significant piece, then the
situation is completely different and much more relevant as a
motivation for the results presented in your paper. But from the
numbers you provide I can't tell. If your primary motivation for our
BNSSA measurement is a completely irrelevant correction to the p-rad
puzzle, it's counter-productive. If it's in fact relevant, and can
potentially amount to a non-trivial part of the p-rad discrepancy,
then that has to be made crystal clear. <br>
<br>
Has someone checked the formulas? (I haven't!).<br>
<br>
In the 1st sentence of the 2nd paragraph in the 2nd column on p. 2,
you define BNSSA as when the pol. is normal to the scattering plane.
How can you do this when we have an azimuthally symmetric detector
with essentially 8 different scattering planes?<br>
<br>
Run 1 vs Run 2: This comes up a few times but I really think it's
confusing jargon and should be avoided in a short paper like this.
Some other way of distinguishing the 3 groupings of measurements
should be done, or maybe nothing should be done. The fact they are
separated in time is not really relevant and could just be mentioned
once, casually, and then you just deal with 1 horizontal and 2
vertical measurements.<br>
<br>
"Data set": You use this for slugs, for runs, for Run 1 and Run 2,
for H & V, in other words, you use it for everything and never
define it. It's jargon. It needs to go. Sorry.<br>
<br>
Bottom of page 3: You make the 1st reference to "3 data sets" which
put me off balance. I only realized later that you are presenting
the 2 V and 1 H measurements- I think this needs to be made clear up
front, before you refer to "... the three data sets."<br>
<br>
Top of page 4: I would recommend you spend the effort to make it
100% clear what you are presenting as your main result in Table 1:
You say it's the avg of the fits- what does that mean? I have no
idea. Both fits? Each fit? 3 fits? Even if I assume you mean each
fit, the asymmetries vary from -4 to +4 ppm in Fig. 1. You fit them
with Eq. 3. What is presented in Table 1, labeled "physics
asymmetries"? It can't be A_det from Eq. 3 because A_det depends on
phi_det. I don't know (in principle) where the numbers in Table 1
come from or what they could possibly be. You absolutely have to
clearly define what you mean by A_exp.<br>
<br>
The fits: they should be explained much more clearly. What was
floated in the fit, and what was not? Was P fixed? To what? Was B_n
varied (I assume it was, and that it's the mystery result you
present as A_exp in Table 1). But what about what you call the
"floating phase offset" phi_det? That's not floated, it's known for
each detector. Is there some other thing called phi_det you actually
do float in the fit? If so what is it, what value does it have, is
it 1 floated variable in your fit or 8? Also, what is the "floating
constant"? Is that also 8 variables or one? What value comes out?
You only have 8 points to fit- it's important to spell out exactly
how many free parameters are floated in the fit and what they are.
It seems to me there should be only 2: B_n and phi_s. And phi_s is
the fudge factor you talk about as both the "floating phase offset"
and "floating constant". <br>
<br>
Finally, only 2 curves show up in Fig. 1. What about the second set
of results with V polarization?<br>
<br>
The 2nd sentence on p. 4 seems out of place and confusing: an
"acceptance" of 49% of 45 degrees? Is that technically an
acceptance? The word "only" in front of 49% bugs me too. And what
does this have to do with anything anyway? I don't get it. I
certainly don't see the connection (if that's what you are trying to
do here) to the next sentence: The 3rd sentence on p.4: Are you
referring here to the correction for going from <A(Q^2)> to
A(<Q^2>)? That was R_Det=0.980 in Wien 0. What the heck is
this 0.9938 correction? Finally, 4 digits seems extreme, whatever
this correction actually is. Is it? Maybe not.<br>
<br>
middle of 1st column, p4: Could you elaborate a little more how the
inelastic bkg f and A were measured?<br>
<br>
When putting a negative sign in front of a number like 5.0, always
use $-$5.0 because the math mode minus is bigger. Don't leave a
space between the - sign and the number, either.<br>
<br>
Your factors that go into R_tot are all different from our Wien 0
numbers. Is this a mistake? I'm not aware that this was revisited.<br>
<br>
You should explain how you go from the 3 mystery numbers in Table 1
to the single B_n you report 1/3 of the way down the 2nd column on
p. 4. I assume you did a weighted average somewhere. <br>
<br>
Relative error table: relative to what? To B_n?<br>
<br>
I was surprised not to find any discussion about how well the
calculations do with other data out there- doesn't G0 have a result?
Perhaps you don't have the results of the predictions at the G0
kinematics. But I seem to recall there was something.<br>
<br>
I assume you don't have error estimates for the other 2
calculations?<br>
<br>
Finally, there is a lot of space in the intro building up the
connection to the p-radius and magnetic moment business. But at the
end I don't see a firm connection. Only a soft one. Can you make a
more quantitative statement about the impact this has on the 7.7
sigma puzzle for example? Or on the ingredients to that puzzle? It
seems to fall a bit short of expectations otherwise. It certainly
stands on its own, however, with respect to what we learn about the
importance of these multi-pion excitations. That's very solid. If
the p-radius connection is really so soft, perhaps it would be
better to de-emphasize that to some extent in the intro and build up
the connection to testing aspects of the calculations and learning
more about the TPE process instead.<br>
<br>
References: I did not check them yet. Somebody should eventually.<br>
<br>
OK, again, thanks a zillion for all the work you put into this. It's
a great job!<br>
<br>
Greg<div><div class="h5"><br>
<br>
<br></div></div></div></div>-- <br><div class="gmail_signature"><div dir="ltr"><font face="georgia, serif">-------------------------------------------------------------------<br>Buddhini Waidyawansa<br></font>Postdoctoral Fellow<br>
C122,<br><div><font face="georgia, serif">12000 Jefferson Ave,</font></div><div><font face="georgia, serif">Newport News, VA 23602.</font></div><div><font face="georgia, serif">TP 757-912-0410</font></div></div></div>
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