comments to paper on high pt

From: Flemming Videbaek (videbaek@rcf.rhic.bnl.gov)
Date: Sat Jun 28 2003 - 20:43:09 EDT

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    Hi these are my final comments fore going away for about 2 weeks
    
    Comment to the Saturday version (6/28) of the paper:
    (note added - more refs are in fact being added to address some issues
    mentioned early in this note)
    
    One big concern I have is that at present it is very much self centered.
    At some level one should be so but we have to
    acknowledge that result on pt-suppression has already been obtained by
    STAR,Phenix 130,200GeV + pi0's, an by Phobos at
    200. For the d-Au the other publication S,P,P do cross reference their
    submitted papers and we should do so too. I know
    the refs are not there yet, but the sentences to support this is neither.
    This can be done several places.
    n       At the end of the intro. "this is what is referee to as high pt
    suppression". for the Au-Au
    n       During discussion of our own data.
    
    --Fig 1. Should it not be labeled as invariant spectra?
    -Fig 1 the percent italic seems mixed up.
    
    I am honestly confused on the trigger setup for Au-Au. As far I remember
    we took very little down-scaled ZDC triggers, but
    a reasonable amount of BB. The central cuts (0-25%) were base on ZDC+MULT.
    I do not know how the higher percentages were
    selected in the analysis which may have been on ZDC.
    I am in part saying this because the 97% as far I recall o NOT refer to ZC
    but to BB/MULT efficiency>
    I have never seen the total ZDC eff. Vs interaction cross section.
    
    
    
    >>My page no are not anyone else sinceI ran my own latex on the text+figs.
    
    Par "Centrality selection."
    End -> "around the IP"  (IP is already defined above).
    Par "Figure 1.
       The percentages list needs some spaces.
    Later + "Also shown in the figure.."  "is our measured minimum bias
    spectrum."
    In the "consequently.. It should be spelled out we use the "estimated h-
    spectrum" as we have gone through
    
    Next Par. I
    " A common way to compare. Possible a reference ? In any case it is useful
    I think to give the formulae. It is supposedly
    for the 'general reader" !
    par "Figure 2." sentence 3
    ",whereas a scaling with larger Nbin  values reduces.." This is a bit
    unclear to me at least if taken literal.
    ".,whereas a scaling to with the larger nbin values shows a reduced."
    
    Cronin effect : 'due to multiple scattering of nucleons .." Is it not ue
    to multiple scattering of incident partons.."?
    
    Last sentence of par - It does show up later but the cancellation is
    mainly all "except for those arising form the Nbin
    determination".
    
    In this par one could add a ref to the S,PP ata if not already done ~ mi
    par. "The data of RAA at 200 GeV at eta=0 are in
    good agreement with those shown/presented by S,P,P in ref .bla bla "
    
    
    In the d-Au section:
    "we have verified that the shape." I have NOT seen this evidence, and it
    is contrary to a plot that JH have shown at least
    at BNL which showe the ratio of DN/dpt vs pt at eta=0 for a very central
    vs very per selection have a fairly large change.
    I will suggest removing this statement for now.
    
    Summary section:
    Could we find another name for dAu than "a light mass nucleus", The actual
    point is in fact it is closer to a proton i.e
    single hadron than nucleus.
    
    In the summary I hope we can find a way to be more precise. The word
    'initial" .. is use in at least two distinct
    different meanings.
    
    To be more specific:
    "The observation of Cronin like effect in d-Au rules out the cause of
    suppression as being due to a initial gluonic
    saturation  at eta~0 {the cronin effect itself is an initial state effect
    namely kt broadening of the incident partons".
    Thus the explanation has to be otherwise. It could be due to the energy
    loss (absorbtion) at the level of the OUTGOING
    partons (final state effect though early) (a la Vitev, Guylassy), due to
    rescattering at a somewhat later hadronic level
    (Gallmeister,Greiner,..) or to some on unexplored mechanism..
    
    As the summary stands I am unhappy. I think , if agreed upon, one can
    re-write base on the above observations..
    
    On the figures. I know the syts errors are in progress. I hope we can make
    them such that the different plots
    e.g RAA, RCP and double RCP have the proper different ones (Nbin
    part(12-20%), cross ection part (~10-15%) , others (??))
    both at bans as defined in the caption where they come from.
    
    
    
    In summary I hope anyone with  interest in the outcome of the paper sends
    the comments ASAP to the committee (IGB, KH, ZY,
    CEJ), and too that the committee consults by phone with each institution
    before submission to ensure we have reached a
    consensus. I see this as the mechanism since I am not available after
    today (Saturday, and Jens Jorgen not from Tuesday)
    
    
    
    cheers
        Flemming
    
    ------------------------------------------------------
    Flemming Videbaek
    Physics Department
    Brookhaven National Laboratory
    
    tlf: 631-344-4106
    fax 631-344-1334
    e-mail: videbaek@bnl.gov
    
    
    -- 
    Flemming Videbaek
    Brookhaven National Laboratory
    Physics Department
    tlf 631-344-4106
    fax 631-344-1334
    e-mail: videbaek@bnl.gov
    


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