Re: pbar/p paper

From: Jens Jorgen Gaardhoje (gardhoje@nbi.dk)
Date: Thu Jan 25 2001 - 11:48:39 EST

  • Next message: J.H. Lee: "Re: BRAHMS first publication"

    Michael Murray wrote:
    
    DEAR MICHAEL
    
    Many thanks for your mail. I have responded to JHL and to the list  with
    my views on the general publication strategy. I feel that expediency is
    more important than elegance in our situation.
    
    > 
    > Micha     Dear Jens  Jorgen,
    >                                  thanks very much for sending out the two
    > drafts. Here are some remarks on
    > the ratios paper.
    > 
    > My first  question is does the mechanism of stoppiing change from pp to AuAu?
    > At the ISR the R-807 collaboration measured pi+-, k+-,p and pbar from pp and
    > pbarp coolisions.
    > They find that 16% of the pbars observered at y=0 come from the fragmentation of
    > the beam.
    > Note each beam had an energy of 26GeV so sqrt(s)=52GeV. They found pbar/p=.6 for
    > pp collisions.
    > This seems very close to our situation.
    
    Indeed. I have on my desk the old Boeggild and Ferbel ARNS on IRS p+p.
    it also looks as if 
    the ratio at y=2 is not too far from ours . Food for thought?
    
    > 
    > I could not find anything about pbar/p from alpha alpha collisions at the ISR.
    > There may be
    > something in CERN-EP/84-112 by M.A. Faessler but I could not find the report on
    > the Web. Hans should be an
    > expert.
    
    He is at CERN right now. Could you pursue it with him?
    
    > 
    > If you are going to report K+/K- and pbar/p why not try to connect them. It
    > would be simple to
    > do a chemical analysis at y=0. At  QM01 people were even saying that you should
    > only use the
    > central rapidity ratios at sqrt{s}=130GeV. Another nice way of doing this would
    > be to plot
    > pbar/p versus k+/k- versus sqrt{s}. This should show a clear trend. One could
    > put pp results on
    > the same plot.
    
    Would you prepare a figure? We will need it anyway. If not for this
    paper then for talks 
    and certainly in early June when we fill in the 100+100 point in a
    pre-written paper!
    
     
    
    > 
    > Do we still have strong pbar absorbtion at RHIC?
    > does pbar/n_part  (or pbar/pi) increase with centrality? At the SPS it was flat.
    > 
    > I think it would be very useful to try to get a k+/k- ratio in the FRS.
    
    Ian is looking at this. there is a little tiny corner in the acceptance
    at very low pt that could be clean iun the toF vs p plot. If ready it
    should go in.
    
    
    
    > One idea would be to devide the mass**2 spectra directly. Presumably the pion
    > contamination in the decreases with mass**2 and so the ratio should approch the
    > true
    > value for mass**2=.3 or so.
    > 
    > I think it would be very good to convert the tex to latex and to include the
    > plots as .eps files.
    
    RAMI has done the dndeta, and promisewd the pbar/p for the weekend.
    
    > I have included some references that may be useful. I will find the model ones
    > too.
    
    Many thanks
    
    Cheers 
    JJ
    
    >              Yours Michael
    > 
    > \bibitem{ZDCNim}  % The RHIC Zero Degree Calorimeter
    >  C. Adler, et al., submitted to Nuclear Instruments and Methods,
    > xxx.lanl.gov/abs/nucl-ex/0008005
    > 
    > \bibitem{NA44PbPbK} % Strange Meson Enhancement in PbPb Collisions at 158 GeV/c
    > Bearden, I.G. et al.; Phys. Lett. B 471, 6-12 (1999)
    > xxx.lanl.gov/abs/nucl-ex/9907013
    > 
    > \bibitem{ NA44Spbar} %Proton and Antiproton Distributions at Midrapidity in
    > Proton-Nucleus and Sulphur-Nucleus Collisions
    > Bearden, I.G. et al.; Phys. Rev. C57 837-846 (1998)
    > 
    > \bibitem{NA44SAK} % Charged Kaon and Pion Production at Midrapidity in
    > Proton-Nucleus and Sulphur-Nucleus Collisions} \\
    > Boggild, H. et al.; Phys. Rev. C59 328-359 (1999)
    > xxx.lanl.gov/abs/nucl-ex/9808002
    > % K-/K+ at y_cm falls from pBe to SPb while pbar/p increases.
    > 
    >  \bibitem{ NA49pbar} % Antiproton production in nuclear collisions at 158 A
    > GeV/c
    > G.I. Veres et al., Nucl. Phys. A 661 383c-386c.
    > \bibitem{NA49stop} %Stopping: from peripheral to Central Nuclear Collisions at
    > the SPS
    > G.E. Cooper et al.,    Nucl. Phys. A 661 362c-365c
    > % Beautiful proton distributions versus rapidity and centrality.
    > 
    > \bibitem{NA49kaon}  % Strangeness production in nuclear collisions-recent
    > results from NA49.
    > C Hohne et al.,     Nucl. Phys. A 661 485c-488c
    > % Shows k+/pi and k-/pi vs sqrt{s} for AA and pp
    > \bibitem{NA49QM99} F. Sikler et al., % Hadron Production from NA49 at 158GeV/c/A
    > % K+ and K- increase with n_part whereas pbar does not
    > \bibitem{NA52QM99} %Impact parameter dependence of pi+-,K+- ,pbar,d & dbar for
    > PbPb
    > S. Kabana et al.,  Nucl. Phys. A 661 370c-373c
    > % At low Pt pbar/n_part FALLS as n_part increases while K+/n_part and K-/n_part
    > increase.
    > el Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899
    
    -- 
    ____________________________________________________
    JENS JORGEN GAARDHOJE
    Assoc. Prof. of Physics, Dr. Scient.
    
    Niels Bohr Institute, 
    University of Copenhagen
    Blegdamsvej 17, 2100 Copenhagen
    Denmark.
    
    Tlf: (+45) 35 32 53 09 (dir) 
         (+45) 35 32 52 09 (secr)
    Fax: (+45) 35 32 50 16
    Email: gardhoje @ nbi.dk
    Home page: http://alf.nbi.dk/~gardhoje
    
    -Chair Ph. D. School of Physics at NBI.F.AFG.
     (secr. Frank Kristensen 35 32 04 41, Ørsted Lab.)
    -Member Danish National Commission for UNESCO 
     (secr. Ulla Holm 35 32 52 72, NBI)
    ___________________________________________________
    



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