Re: [Brahms-dev-l] FW: Your_manuscript CS10219 Arsene

From: flemming videbaek <videbaek_at_bnl.gov>
Date: Sun, 26 Sep 2010 15:17:58 -0400
Hi

I updated mainly the experimental discussions (with errors,...) and  
also added a few places where the centrality range was either omitted  
or wrong (0-20%).
The updated pdf can be found on
http://www4.rcf.bnl.gov/~videbaek/analysis/auau62/dpAuAu.pdf

The cvs repository tex file is also updated.

F.

Flemming Videbaek
videbaek @ bnl.gov
Brookhaven National Lab
Physics Department
Bldg 510D
Upton, NY 11973

phone: 631-344-4106
cell     :  631-681-1596





On Sep 23, 2010, at 9:02 PM, Ramiro Debbe wrote:

> Hi All,
> I attach here the dpAuAu paper with the modifications that address  
> the referee comments (magenta) I have also added a few more  
> references. Please read it and let us know your opinion. Flemming  
> will do some additional work in the blue sections.
> Ramiro
> <dpAuAu.pdf>
>
> On Sep 16, 2010, at 7:38 PM, Ramiro Debbe wrote:
>
>> Hi All,
>> I have placed the dp paper and it possible modification in the  
>> Indico page. I have not had enough time to finish what I wanted to  
>> accomplish but I wrote some lines that we can discuss tomorrow.
>> Ramiro
>> On Sep 2, 2010, at 10:05 PM, Ramiro Debbe wrote:
>>
>>> Hi All,
>>> I have placed the dp paper in the Indico agenda for tomorrow's  
>>> meeting. The paper has Flemming's comments (blue) as well as a new  
>>> version of the figures, and my comments  (magenta).
>>> Thanks,
>>> Ramiro
>>> On Sep 1, 2010, at 9:14 PM, Ramiro Debbe wrote:
>>>
>>>> Hi All,
>>>> I added some suggested changes to the dp paper to accommodate the  
>>>> referee comments (I used my old magenta color to highight that  
>>>> text).  I was unable to see if I can still build the pdf version  
>>>> because rcf2 is not working well and I did my work on an rcas  
>>>> machine. I committed the changes back to CVS. Hopefully I can  
>>>> generate a pdf version before the meeting on Friday.
>>>> Ramiro
>>>> On Aug 24, 2010, at 12:44 PM, Ramiro Debbe wrote:
>>>>
>>>>> Hi Michael,
>>>>> I was very exited when I saw the extent of the referee comments  
>>>>> and started looking at possible actions, I think we can improve  
>>>>> the paper greatly.
>>>>> I went thru some of our references, found a few new ones, mainly  
>>>>> looking for a more recent point of view and I asked around  
>>>>> (mainly about comment 5)
>>>>> I add some suggestions after the referee comments.
>>>>> Ramiro
>>>>> On Aug 6, 2010, at 5:20 PM, Murray, Michael J wrote:
>>>>>
>>>>>> FYI
>>>>>>
>>>>>>
>>>>>> Michael
>>>>>>
>>>>>>
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: prc_at_aps.org [mailto:prc_at_aps.org]
>>>>>> Sent: Fri 8/6/2010 12:48 PM
>>>>>> To: Murray, Michael J
>>>>>> Subject: Your_manuscript CS10219 Arsene
>>>>>>
>>>>>> Re: CS10219
>>>>>>    Rapidity dependence of deuteron production in Au+Au  
>>>>>> collisions at
>>>>>>    sqrt s NN=200 GeV
>>>>>>    by I. Arsene, I. G. Bearden, D. Beavis, et al.
>>>>>>
>>>>>> Dear Dr. Murray,
>>>>>>
>>>>>> The above manuscript has been reviewed by one of our referees.  
>>>>>> Comments
>>>>>> from the report appear below.
>>>>>>
>>>>>> These comments suggest that specific revisions of your  
>>>>>> manuscript are
>>>>>> in order. When you resubmit your manuscript, please include a  
>>>>>> summary
>>>>>> of the changes made and a succinct response to all  
>>>>>> recommendations or
>>>>>> criticisms contained in the report.
>>>>>>
>>>>>> Yours sincerely,
>>>>>>
>>>>>> Bradley Rubin
>>>>>> Senior Assistant Editor
>>>>>> Physical Review C
>>>>>> Email: prc_at_ridge.aps.org
>>>>>> Fax: 631-591-4141
>>>>>> http://prc.aps.org/
>>>>>>
>>>>>> Physics - spotlighting exceptional research: http://physics.aps.org/
>>>>>>
>>>>>> PROBLEMS WITH MANUSCRIPT:
>>>>>>
>>>>>> In reviewing the figures of your paper, we note that the  
>>>>>> following
>>>>>> changes would be needed in order for your figures to conform to  
>>>>>> the
>>>>>> style of the Physical Review.  Please check all figures for the
>>>>>> following problems and make appropriate changes in the text of  
>>>>>> the
>>>>>> paper itself wherever needed for consistency.
>>>>>>
>>>>>> Figure(s) [4]
>>>>>>          Please rearrange power of 10 in axis label for  
>>>>>> clarity:  Either
>>>>>>          (i) place the power of 10 as a factor, without  
>>>>>> parentheses,
>>>>>>          in front of the axis label quantity, changing the sign  
>>>>>> of the
>>>>>>          power as needed; or (ii) incorporate the power of 10  
>>>>>> in the
>>>>>>          topmost or rightmost number on the scale.  Please  
>>>>>> refer to
>>>>>>          the URL http://forms.aps.org/author/ 
>>>>>> h18graphaxislbls.pdf for a
>>>>>>          pictorial representation of the preferred forms for  
>>>>>> axis labels.
>>>>>>
>>>>>> Figure(s) [please check all and amend where necessary]
>>>>>>          The lettering in the axis labels and/or numbering size  
>>>>>> should be
>>>>>>          increased. Please ensure that all lettering is 2 mm or  
>>>>>> larger
>>>>>>          (1.5 mm for superscripts and subscripts) after scaling  
>>>>>> to the
>>>>>>          final publication size. Note that the column width is  
>>>>>> 8.6 cm
>>>>>>          (twice that amount plus gutter for extra wide figures).
>>>>>>
>>>>>>
>>>>>> Please remove the redundant arXiv references for published  
>>>>>> papers.
>>>>>> For your information, the editorial office checks the  
>>>>>> references at
>>>>>> several crucial steps during the editorial process. A list of  
>>>>>> unnecessary
>>>>>> arXiv references slows the process down considerably-- 
>>>>>> particularly so,
>>>>>> if the list is long--and delays the processing of your  
>>>>>> manuscript.
>>>>>>
>>>>>> Please note that the copy editors will remove such redundant  
>>>>>> links during
>>>>>> production for those papers that have been accepted for  
>>>>>> publication.
>>>>>> However, any manual intervention carries the risk of  
>>>>>> inadvertently
>>>>>> introducing mistakes.
>>>>>>
>>>>>> ----------------------------------------------------------------------
>>>>>> Report of the Referee -- CS10219/Arsene
>>>>>> ----------------------------------------------------------------------
>>>>>>
>>>>>> Executive Summary:
>>>>>> -----------------------------------------
>>>>>> The paper is a straightforward, almost minimalist, presentation
>>>>>> of a data set on proton and deuteron production in central Au+Au
>>>>>> RHIC collisions over a wide range of rapidity, and antiproton and
>>>>>> antideuteron production over a smaller range in rapidity.  The
>>>>>> data are interpreted in terms of a standard coalescence picture
>>>>>> and an extracted phase space density; some trends are noted but
>>>>>> no definite physics conclusions are drawn.  As a simple data
>>>>>> presentation exercise the paper is generally acceptable, though
>>>>>> the physics impact of the data are significantly limited by
>>>>>> being restricted to only central collisions in only one bin of
>>>>>> centrality.
>>>>>>
>>>>>> Though I would not suggest it as a requirement for publication
>>>>>> in the Physical Review, I would urge the authors to consider
>>>>>> enlarging the paper to include data from a greater range of
>>>>>> centrality classes -- based on the error bars shown in Fig 5
>>>>>> it certainly looks as though sufficient statistics would be
>>>>>> available.
>>>>>>
>>>>>> Modulo that decision, the paper has a number of minor errors
>>>>>> in the physics introduction which should be addressed, as
>>>>>> detailed below.  My basic recommendation, then, is that the
>>>>>> paper will be suitable for publication with minor corrections.
>>>>>>
>>>>>>
>>>>>> Concerns:
>>>>>> --------------------------------------
>>>>>> (1) Centrality selection.  The data presented in Fig 3 are for  
>>>>>> some
>>>>>> particular event selection; but which?  One needs to scan the
>>>>>> paper in some detail (or use a computer text search) to find
>>>>>> the lone sentence "We present ... AuAu collisions with a  
>>>>>> centrality
>>>>>> range of 0-20%."  in the first paragraph under Section II.  
>>>>>> Analysis.
>>>>>> (Note that this sentence itself is not quite grammatically  
>>>>>> correct.)
>>>>>>
>>>>>> Physics: Why was this one, and only one, centrality range chosen
>>>>>> for this analysis?  There is no motivation mentioned in the paper
>>>>>> at all, which is quite puzzling.  The paper describes  
>>>>>> interpretation
>>>>>> in terms of geometrical quantities such as the coherence volume  
>>>>>> implied
>>>>>> by the B_2 measurement; it is only natural to ask, then, how  
>>>>>> these
>>>>>> might change as the collision geometry/centrality is changed.  To
>>>>>> present data from only one centrality selection, with no  
>>>>>> explanation,
>>>>>> seems quite odd and un-natural, and I would call it a glaring  
>>>>>> defect.
>>>>>> There is of course a limit on available particle statistics,  
>>>>>> but it
>>>>>> is far from clear (partly because there is so little detail  
>>>>>> provided
>>>>>> on the error analysis) that no statement could be made for any  
>>>>>> other
>>>>>> selections, even by breaking the current one into two.
>>>>>>
>>>>>> Analysis: The section on the data analysis should include a  
>>>>>> description
>>>>>> of how the events were selected on centrality.
>>>>>>
>>>>>> Formatting: Assuming that the paper is to be published on just  
>>>>>> the
>>>>>> central collision results, that fact should be made clear  
>>>>>> throughout
>>>>>> the work: it should appear in the title, in the abstract, in the
>>>>>> summary and in the captions of all the figures and tables.  And,
>>>>>> for that matter, the main data graphs such as Fig 3 should also
>>>>>> state that these results are for the Au+Au collision system!
>>>>>>
>>>>>>
>>>>>> (2) Error analysis.  The presentation in Table I does a good  
>>>>>> basic job
>>>>>> of explaining the uncertainties: statistical errors are in the  
>>>>>> table,
>>>>>> systematics are characterized in the text.  All of the figures  
>>>>>> and
>>>>>> tables should rise to this same standard:  what is shown by the  
>>>>>> errors
>>>>>> that are displayed?  and what are the sizes of the other sources?
>>>>>>
>>>>>> Elsewhere the treatment of uncertainties is uneven.  The  
>>>>>> discussion
>>>>>> of errors from the feed-down correction in Section II.D is quite
>>>>>> quantitative; while the preceding section II.C on particle
>>>>>> identification describes inefficiencies and contaminations, but  
>>>>>> does
>>>>>> not quote anything quantitative for the residual uncertainties  
>>>>>> from
>>>>>> these effects.  At a minimum the reader should be able to  
>>>>>> appreciate
>>>>>> the relative contributions of statistical versus systematic
>>>>>> uncertainties, and what the dominant source is for the  
>>>>>> systematic,
>>>>>> for every quantity quoted and plotted in the paper.
>>>>>>
>>>>>>
>>>>>> (3) Abstract: "in contrast to lower energy data".  This should be
>>>>>> re-worded to make clear that it refers to data from collisions
>>>>>> at lower collision energies, rather than lower secondary particle
>>>>>> energies.
>>>>>>
>>>>>> (4) p1 col2: "surrounding ... medium ensure energy and momentum
>>>>>> conservation".  "Ensure" would be better as "allow" or "permit"
>>>>>> or "enable".  Conservation laws always "ensure" that they are
>>>>>> followed; the role of the medium is to "allow" p + n -> d
>>>>>> to proceed without the need to emit a photon.
>>>>>
>>>>> I suggest to change the sentence: "In free space ....." by the  
>>>>> following
>>>>> "The surrounding medium created in the A+A collisions enables  
>>>>> this 2->1 process to
>>>>> proceed while it conserves energy and momentum."
>>>>>>
>>>>>>
>>>>>> (5) p1 col2 "As deuterons are formed inside the expanding system"
>>>>>> Is this really true?  How do you know?  One could make the simple
>>>>>> argument that particle within the medium are colliding often
>>>>>> enough, on the order of once per ~1-10 fm/c or faster in the time
>>>>>> before freezeout, then the constituent protons and neutrons will
>>>>>> on average be off their mass shell by ~200-20 MeV at any given
>>>>>> moment; if this is true, then how can one even distinguish a
>>>>>> deuteron bound state, whose binding energy is only 2 MeV?
>>>>>> The bound/unbound distinction doesn't apply over such short
>>>>>> time scales.
>>>>>>    The same misconception appears later in the same paragraph
>>>>>> with the phrase "deuterons are most likely formed very near
>>>>>> freeze-out".  What, exactly, does "formed" mean here?  In order
>>>>>> for a p,n pair to be meaningfully distinguished as either bound
>>>>>> or unbound, the degree to which they are off-mass-shell must be
>>>>>> no larger than the bound-state binding energy.  This implies that
>>>>>> bound-state deuterons cannot even be _defined_ until ~100 fm/c
>>>>>> have passed since the particles' last momentum transfer
>>>>>> interaction, ie freezeout; this time frame cannot be described
>>>>>> as "very near freezeout."  It really makes no sense to say that
>>>>>> deuterons are "formed" on a timescale faster than they can even
>>>>>> be distinguished or defined, whether inside the colliding system
>>>>>> or following freezeout, so this whole passage of the
>>>>>> introduction is really misconceived.
>>>>>>    The reason that sudden-approximation coalescence models can
>>>>>> work is more subtle, quantum mechanically.  After the last
>>>>>> momentum exchanges, ie freezeout, all the protons and neutrons
>>>>>> will be in wavefunctions which span a range of masses around
>>>>>> their free-particle on-shell rest mass.  The off-shell
>>>>>> combinations of momentum and energy will decay away with time,
>>>>>> ie the amplitude of those parts of the wavefunctions will
>>>>>> diminish and only the on-shell states will have significant
>>>>>> amplitudes.  So, looking into the future at the time of
>>>>>> freezeout it is reasonable to count only the on-shell states
>>>>>> for future accounting purposes; but the off-shell states are
>>>>>> still present in the wavefunction at that time.
>>>>>>    For this reason, one can get reasonable answers from a
>>>>>> coalescence model while neglecting these off-shell subtleties.
>>>>>> But, by the same token, there is no excuse at this point in
>>>>>> the field for leaving a sloppy definition of "formed" in the
>>>>>> introduction to a paper like this, and the section should be
>>>>>> rewritten without this misconception.
>>>>>>
>>>>> Even though recent publications (PHENIX) use similar language, I  
>>>>> detect a consensus
>>>>> in the papers I read but mostly from the responses I get when I  
>>>>> asked other
>>>>> colleagues with experience in the subject. I suggest we state  
>>>>> the following and add a recent paper:
>>>>>
>>>>> In the hot and dense system formed in high energy collisions,  
>>>>> the coalescence of nucleons into deuterons
>>>>> is not possible before it reaches a stage where hadrons are  
>>>>> present, and even then, the low binding energy of deuterons  
>>>>> (2.24 MeV),
>>>>> force this process to happen only late, near the so called  
>>>>> thermal freeze out, where the nuclear density is low but still  
>>>>> high enough to allow
>>>>> for interactions that put all participants back on mass shell.    
>>>>> \cite{Ioffe}
>>>>>
>>>>>>
>>>>>> (6) p1 col2: "Coalescence models assume that the distribution
>>>>>> of clusters..."; "density" or "phase-space density" would be
>>>>>> better than "distribution"
>>>>>>
>>>>>>
>>>>>> (7) p1 col2 and Eq. 1: The references [1-3] quoted to
>>>>>> introduce the notation of the coalescence picture in Eq. 1
>>>>>> are incomplete; they date from the Bevelac era (or earlier),
>>>>>> when the notation C_2 was used for the proportionality
>>>>>> similar to that in Eq. 1 but with cross sections rather than
>>>>>> per-event densities.  The B_2 notation used here was originated
>>>>>> during the AGS fixed-target heavy-ion program, starting with
>>>>>> E858 and then E864 and E878; and it is a rather glaring
>>>>>> omission that not all of these experiments are referenced in
>>>>>> this paper, which should be corrected.
>>>>>>
>>>>> We could drop the 1-3 or add to them a more recent review:  
>>>>> L.R.Csernai, J.I.Kapusta, Phys. Rep. 131, 223 (1986);
>>>>> We should add the E858 E864 and E878 references.
>>>>>>
>>>>>> (8) p1 col2: Mention is made of the n/p ratio in lower-energy
>>>>>> collision data, but the meaning and significance are not clear
>>>>>> at all.  What system was this for?  Does this n/p ratio
>>>>>> correspond to that of the incoming nuclei, or not?  Is the
>>>>>> implication that Eq. 1 should be modified, or assigned a 20%
>>>>>> systematic error?  If not, why not?  The bare inclusion of
>>>>>> this observation, without any details, explanation or
>>>>>> implication is simply confusing and not helpful to the reader.
>>>>>>
>>>>>>
>>>>>> (9) p2 col1: "B_2 carries information about the cluster"
>>>>>> What do you mean by "cluster"?  Is it the deuteron itself, as
>>>>>> implied on the previous page with the phrase "the distribution
>>>>>> of clusters"?  Or does "cluster" mean the system as a whole?
>>>>>> Neither really makes sense; B_2 doesn't really tell you
>>>>>> anything about the deuteron itself per se; and it's strange,
>>>>>> as well as inconsistent with the previous page, to refer to
>>>>>> refer to the whole system as a "cluster".
>>>>>>
>>>>> This sentence now reads bad. B_2 is related to the volume of the  
>>>>> source of deuterons. For a while
>>>>> we tried to be general and used clusters to include d, He3, and  
>>>>> other heavier systems, I suggest to remove
>>>>> the word cluster and replace by deuteron. And rewrite this  
>>>>> sentence:   effective volume of the nuclear matter at the time  
>>>>> of coalescence
>>>>>
>>>>> In thermodynamical models that assume thermalized distributions  
>>>>> of nucleons, B2 carries information about the effective volume  
>>>>> of the nuclear matter at the time of coalescence:
>>>>> [1–3].
>>>>>
>>>>> more comments below point to our confusion of of coalescence  
>>>>> volume and deuteron source volume, we should just keep  
>>>>> coalescence volume.
>>>>>
>>>>>> (10) p2 col1: "B_2 ... is consistent with measurements of
>>>>>> the deuteron wave-function."  This is a very strange and
>>>>>> jarring statement to read at this point in the paper, since
>>>>>> there has been no discussion up to this point on how the
>>>>>> deuteron's spatial properties figure into the value of B_2
>>>>>> through the coalescence process or otherwise.
>>>>>
>>>>> We need to move the next sentence where we mention the Wigner  
>>>>> functions up before this discussion.
>>>>> By the way, the sentence mentioning Wigner functions is  
>>>>> describing a particular case of sudden-approximation coalescence  
>>>>> model.
>>>>>>
>>>>>> (11) Also, this statement is referenced to Ref 5, but only
>>>>>> vague mention is made of what collision systems or what
>>>>>> collision energies are being referred to; this makes it
>>>>>> somewhat strange to read in the very next sentence that
>>>>>>> = 4.9 GeV is the threshold of "high energy".  It would
>>>>>> be clearer to state the energy ranges, and at least whether
>>>>>> heavy or light nuclei are involved, for all the data being
>>>>>> referred to (this remark applies in several other places
>>>>>> throughout the current paper, as already mentioned in
>>>>>> point 8 above).
>>>>>
>>>>> Needs work
>>>>>>
>>>>>> (12) p2 col1: "assuming the region where the coalescence
>>>>>> occurs has also a Gaussian shape"  See point 5 above; the
>>>>>> region which sources/radiates the nucleons is not the same
>>>>>> thing as the region where coalescence occurs.  Note also
>>>>>> that "spatial profile" would be better than "shape" in
>>>>>> this sentence.
>>>>>>
>>>>>> (13) p2 col1: "this ansatz ... facilitates comparison to
>>>>>> interferometry radii".  A traditional point; but, how does
>>>>>> the comparison work in this case?  First, should the R_G
>>>>>> from the coalescence framework analysis be compared
>>>>>> directly to any of the R parameters from HBT analysis?
>>>>>> or is there a factor of 2, or pi, etc between them?
>>>>>> Is this paper going to actually make the comparison?
>>>>>> if not, then you should provide a reference to how the
>>>>>> comparison should be done.
>>>>>>
>>>>> Shall we try that comparison?
>>>>>
>>>>>> (14) p2 col1: "However, it has been suggested that..."
>>>>>> This certainly needs a reference, or several, at this point.
>>>>>>
>>>>> I agree we need that reference. Voloshin?
>>>>>
>>>>>> (15) p2 col1: The middle paragraph discusses the results
>>>>>> of deuteron production following a quark coalescence picture,
>>>>>> which is a subject of considerable current interest.  However,
>>>>>> the logic is not laid out clearly here.  Isn't it true, for
>>>>>> example, that if protons follow the quark coalescence picture
>>>>>> and deuterons follow the nucleon coalescence picture, then
>>>>>> deuterons automatically/necessarily follow quark coalescence
>>>>>> as well?  ie isn't quark coalescence for deuterons redundant
>>>>>> with nucleon coalescence? and so not really an independent
>>>>>> piece of information.  Alternatively, is the statement that
>>>>>> deuterons follow quark coalescence equivalent to B_2 being
>>>>>> constant with pT?  But here B_2 is not constant with pT, as
>>>>>> we see in Fig 4; doesn't that have immediate implications for
>>>>>> quark coalescence interpretation of the present data?
>>>>>>    In general this section should be written so as to make
>>>>>> it clear to the reader what are, and are not, redundant versus
>>>>>> independent pieces of information.
>>>>>>
>>>>> This requires reading the references we will add to accommodate  
>>>>> comment 14
>>>>>
>>>>>> (16) p2 col1: The start of the discussion of discussion of
>>>>>> phase-space densities in the last paragraph should have at
>>>>>> least a few references right at the beginning, especially
>>>>>> as to the motivations.  Why is this an interesting quantity?
>>>>>> The text mentions (i) an indicator or measure of the degree
>>>>>> of equilibrium, which is directly connected to entropy,
>>>>>> and (ii) "information about ... symmetrization efects".
>>>>>> Reasonable enough; but what's the upshot?  What do the results
>>>>>> shown in Fig 5 demonstrate?  Trends are noted in Section III,
>>>>>> but what about the basic magnitude of the measured quantity?
>>>>>> is it high, is it low?
>>>>>>
>>>>> It is low! but I agree we could invest more effort here. It will  
>>>>> also add to the summary section. (More reading to be done)
>>>>>
>>>>>> (17) p2 col2: The result of Eq. 5 is correct only for a true
>>>>>> global equilibrium, with one universal temperature and where
>>>>>> the particles have equal access to the entire relevant volume.
>>>>>> The text acknowledges this, but only in a roundabout way with
>>>>>> the later remark "we are ignoring the collective motion of the
>>>>>> particles", as collective motion is a departure from true
>>>>>> global equilibrium (also, "neglecting the possibility of" is
>>>>>> more accurate than "ignoring" here).  But since collective
>>>>>> motion probably is the case in RHIC Au+Au collisions, from the
>>>>>> B_2 results shown here as well as a host of other evidence,
>>>>>> it is left unclear to what extent Eq.'s 5 - 9 should still be
>>>>>> considered relevant.  For example, in the statement farther down,
>>>>>> attributed to Ref 23, that strong longitudinal flow could
>>>>>> significantly reduce pion phase space densities, it is not clear
>>>>>> if this is a true result about the actual density or an artifact
>>>>>> of Eq. 5 and its corollaries being invalid in the extraction of
>>>>>> the measured phase-space density.
>>>>>>    In general the utility of a framework which assumes global
>>>>>> equilibrium to a system which probably exhibits only local
>>>>>> equilibrium needs to be explained more carefully; if T is a
>>>>>> function of space, then is Eq. 5 still true at a point?  In
>>>>>> the case of collective motion being significant, is Eq. 3
>>>>>> defined over some relevant coherence volume?  etc.
>>>>>
>>>>> Needs work
>>>>>>
>>>>>> (18) p2 col2: "the maximum space averaged phase-space density,
>>>>>> which is at the center of the Gaussian source."  Sorry, but
>>>>>> this makes no sense at al: a spatial average is not defined
>>>>>> for different points within the space.  The confusion over
>>>>>> the relevant spatial volumes mentioned in point 17 above
>>>>>> is clearly causing serious trouble here.
>>>>>
>>>>> Need to read Pratt paper ref[26]
>>>>>>
>>>>>> (19) p2 col2: In Eq. 9, is R_G a function of particle
>>>>>> momentum, particularly pT?  Presumably so, and if so then it
>>>>>> would be useful to write the dependence explicitly here.
>>>>>
>>>>> According to eq.2 we should make R_G pt dependent.
>>>>>>
>>>>>> (20) Minor formatting: the text following Eq. 5 should
>>>>>> probably be left-justified rather than indented.  It is not
>>>>>> clear whether the text following Eq.'s 4 and 6 should or
>>>>>> should not start new paragraphs, either.
>>>>>>
>>>>>> (21) The presentation of Eq. 6 in terms of chemical potential
>>>>>> is formally correct, but at the same time obscure -- in the
>>>>>> dilute limit, what is the value of these chemical potentials?
>>>>>> Is it just the particle mass, which would make Eq. (6)
>>>>>> equivalent to exp[-mT/T] at all rapidities?  or does it vary
>>>>>> significantly with the net baryon density, which changes
>>>>>> considerably with rapidity (as BRAHMS has made clear in
>>>>>> other measurements)?
>>>>>
>>>>> We need to go back to the text book.
>>>>>>
>>>>>> (22) p5 col2: "expect the ratio of the proton and antiproton
>>>>>> phase densities to be flat"; is this as a function of
>>>>>> rapidity?  or pT?  or both?
>>>>>>
>>>>>> (23) Summary, but also relevant to several sections of the
>>>>>> paper: There is a reasonable interpretation here that the
>>>>>> B_2 and phase space density measurements have information
>>>>>> about the existence of collective flow, particularly what
>>>>>> is called radial flow.  This is certainly valuable and
>>>>>> worth publishing.  However, the current paper doesn't say
>>>>>> much about whether these implications are or are not
>>>>>> consistent with the great body of work that has now been
>>>>>> done on modeling RHIC A+A collisions with hydrodynamics.
>>>>>> It is not necessarily the responsibility of this paper
>>>>>> to make a full-blown analysis, but the reader deserves some
>>>>>> basic orientation: are the results shown here generally
>>>>>> consistent with existing hydrodynamical models?  or is
>>>>>> there some kind of surprise or contradiction brewing?
>>>>>>
>>>>>>
>>>>> We knew our physics points were weak.
>>>>>> _______________________________________________
>>>>>> Brahms-dev-l mailing list
>>>>>> Brahms-dev-l_at_lists.bnl.gov
>>>>>> https://lists.bnl.gov/mailman/listinfo/brahms-dev-l
>>>>>
>>>>
>>>
>>
>



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