OPT-IN: New Λp Cross Sections and its Implication for Neutron Star Equation of State

[Reinhard Schumacher]

Dear Joseph et al.,

Here are my comments on the "New Lambda p... State" paper that is out
for CLAS Collabotation review, hoping to be submitted to PRL.

First of all, congratulations on getting this measurement made.   It
is a real tour de force for CLAS.   The results will be used and cited
often,  I think.

However, there are many problems with this draft paper that I think
need to be addressed before you have a shadow of a chance of getting
it published, let alone in PRL.  Below I outline my main observations
based on a single reading.

First of all, the paper does not deliver what the title promises.
There is nothing in the paper about Implications for the Neutron Star
EOS.   It is fine to mention the connection to neutron star physics
like you do in teh first paragraph (but you need some real scholarly
references, not just unsupported statements or even just "private
communications".   I believe you have to come up with a more modest
title and revise the abstract to not over-promise what is in the
paper.

How about "Elastic Lambda proton scattering between 0.9 and 2.0
GeV/c"?  Do not bother to call it "NEW" because you are writing for the acrhival
journal world, and your result will be "old" very shortly.  In a few
years the "new" in the title will seem silly.

Second, the references are inadequate.   On line 25 you refer to [4]
as the source of data, when in fact that is a theory paper.   In
several places you cite Ref [11] to support procedural steps that you
took in your analysis, but Ref [11] is not a public document.   On
line 32 you draw the reader's attention to other elastic scattering
processes and cite the PDG - which is not appopriate in this context.

Next, starting on line 62 you have a description replete with CLAS
jargon and technical details that are not really relevant to a journal
reader understanding what you did.  Define "DC" "TOF"  "sectors", for
instance.   The sentence about the alternate trigger seems
unnecessary.  

line 121:  In my view you are using a very screwed up notation to
indicate missing mass.  You say "MM(Xp,Lp)", but you do not explain
that what you are computing is the missing mass off everything else to
get the mass of "X", and that "X" in this case is supposed to be the
kaon.  The usual notation is MM(what goes in, what measured things
come out),  without an explicit "X".   I would suggest using standard
notation, but if not, you should explain more clearly what you mean.

line 134:  it would be a great confidence builder for the reader if
you actually showed what you get for the pp cross section.   Your
method is novel, as we in CLAS understand very well.   But you have to
convince the reader. You would help you case to show that you get
correct results for a known cross section using your method.

line 140:  Here your notational problems get a lot worse because you
are using "X" again, but for a different particle!  What virtue is
there in that?   Better would be to use, say, "Y", because then the
reader cannot get confused with "X" (the kaon) versus "Y" (the
hyperon).

Fig 4b:  This seems to be a waste of space and of the reader's
attention.   There is not much to be learned by the reader from 4b
that is not already conveyed by 4a.   I would remove this plot (4b)
and use the space for something more interesting, like the pp elastic
scattering cross section.

Throughout the article you jump from present to past tense many many
times.   Even from one sentence to the next there are needless jumps
in tense.   This is very disconcerting for many readers.   An article
"reads" much better if you pick a tense and stick to it.   Usually
what works best is to write the description of the experiment and its
analysis in consistent PAST TENSE, and then possibly switch once when
you present the results to the readers' mind to PRESENT TENSE.   Don't
jump around.

line 215:  "physically restrained"??

In the discussion of the results starting on line 246 the reader
expects to find the payoff:  the connection to neutron stars.   The
reader is very disappointed:   nothing is offered.

Figure 5:  You neglect to include references to the actual theory
curves (a private communication is not enough).   You do not explain
the input assumptions of the theories, and you do not comment on the
agreement, or lack if it with the CLAS data.    You won't get this
published in a top journal, certaintly not on PRL, without a proper scholarly
discussion of these points.

line 274:  Why would the opening of an inestastic channel INcrease the
elastic cross section?   Unitarity would suggest that the elastic
cross section drops when new channels open up.

That is all for now,
Cheers,

Reinhard