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

Hi Michael,
I am going on vacation next week. I suggest you take the lead and  
discuss it next Friday. JH will setup and lead that meeting

Flemming


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

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





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.
>
>
> (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.
>
>
> (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.
>
>
> (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".
>
> (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.
>
> (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).
>
> (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.
>
> (14) p2 col1: "However, it has been suggested that..."
> This certainly needs a reference, or several, at this point.
>
> (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.
>
> (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?
>
> (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.
>
> (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.
>
> (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.
>
> (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)?
>
> (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?
>
>
> _______________________________________________
> Brahms-dev-l mailing list
> Brahms-dev-l_at_lists.bnl.gov
> https://lists.bnl.gov/mailman/listinfo/brahms-dev-l

_______________________________________________
Brahms-dev-l mailing list
Brahms-dev-l_at_lists.bnl.gov
https://lists.bnl.gov/mailman/listinfo/brahms-dev-l