RE: ratios 3.00 (fwd)

From: Dieter Rohrich (dieter@fi.uib.no)
Date: Tue Jul 02 2002 - 08:09:59 EDT

  • Next message: Fouad Rami: "Re: ratios 3.00 (fwd)"

    Hei Ian,
    
    On Tue, 2 Jul 2002, Ian Bearden wrote:
    
    > A question to Dieter:
    > You say that there is no 'good reason' to fit the data with the exponent
    > 1/4.
    > How can you justify this, when the data clearly favor the exponent 1/4, and
    > in fact a fit to K-/K+=(pbar/p)^a gives a=0.24?
    
    what is the physics reason for **1/4? simple thermal models say **1/3, I
    am not aware of any quark counting argument, dynamical model etc. which
    suggests 1/4. Sure, we can parameterize our data with 1/4, but what do we
    learn from that?
    
    > I guess you have been looking at an old version of the paper, and not the
    > new one (which was out over 12 hours ago :-) ).  In the new plot, both
    > curves are shown, which is the way to go, I think.
    
    No, I am looking at the latest version. The Becattini curve is missing -
    which is the only curve justified by physics (and even this is not really 
    true...).
    Fig. 4 with Becattini and **1/3 is the way to go. If you want
    we can have the **0.24 fit as a parametrization of our data -
    but the only thing we can say is "to guide the eye".
    
    With best wishes,
    Dieter
    
    
    > 
    > > -----Original Message-----
    > > From: owner-brahms-l@bnl.gov [mailto:owner-brahms-l@bnl.gov]On Behalf Of
    > > Dieter Rohrich
    > > Sent: 2. juli 2002 12:44
    > > To: brahms-l
    > > Subject: Re: ratios 3.00 (fwd)
    > >
    > >
    > >
    > > Dear Claus and JJ,
    > >
    > > a few comments:
    > >
    > >
    > > abstract
    > >
    > > second sentence:
    > > remove "and consistent with significant significant nuclear transparency"
    > > Many scenarios may result in ratios like the ones we have measured.
    > > And the main message of our paper is NOT to prove/disprove nuclear
    > > transparency, but to present solid data which may shed light on the
    > > dynamics of the collision. See Chellis' comment.
    > >
    > > third sentence:
    > > remove "source in chemical equilibrium and"
    > > If we use statistcal models AND interprete the parameters as T and
    > > mu_b, we implicitely assume chemical equilibrium. We cannot deduce
    > > from our data and the fitting to a statistical model chemical
    > > equilibrium. This sentence has to go out!
    > >
    > >
    > > Page 2:
    > >
    > > second column, first para.:
    > > add a sentence about our acceptance in pt, i.e. that we typically
    > > cover pt-ranges from x to y .
    > >
    > >
    > > Page 3:
    > >
    > > first column, second paragraph, first sentence:
    > > add a space between approx. and 2
    > >
    > > first column, last sentence, sec. c.,first s.:
    > >
    > > remove "This is consistent with the onset of the boost invariant
    > > plateau around midrapidity proposed by Bjorken."
    > > see comment above and Chellis' comment.
    > >
    > >
    > > Page 4:
    > >
    > > Fig.4:
    > >
    > > remove the fit (pbar/p)**(1/4). As Michael nicely pointed out,
    > > we have good reasons for the (pbar/p)**(1/3) curve, but no
    > > physics argument for the (1/4) fit.
    > >
    > > add the predictions from the statistical model (Becattini et. al.)
    > > Why did you take out this curve???? It can't be too difficult to replot
    > > the curve from Fig. 4, PHYS REV, C64, 024901.
    > > The authors have stated in their paper that the K-/K+ ratio is driven by
    > > the pbar/p ratio and his little dependence on T. And that is what we see.
    > >
    > >
    > > second column, first para.:
    > >
    > > remove "that can be expressed by a power law ..."
    > > See comment above. A fit to a (1/4) power law without a physics
    > > motivation is useless.
    > >
    > > remove "Comparison if the two relations indicates the universal
    > > relationship ,,,,"
    > > See comments above. Too speculative.
    > >
    > > last sentence:
    > >
    > > Rephrase sentence e.g. like this:
    > >
    > > "Within the framework of the statistcal model ([Becattini], solid line),
    > > Fig. 4 suggests, that the baryon chemical potentials decrease
    > > from ub=120Mev at y=3 to ub=25MeV at y=0 - keeping in mind that
    > > this interpretion assumes local strangeness conservation."
    > >
    > >
    > > Second column, second para.:
    > >
    > > remove "suggesting the existence of a boost invariant midrapidity
    > > plateau dominated by particle production from the color field."
    > > Again, we have no evidence for such statements, and we do not
    > > measure particle ratios to discover/prove/disprove boost invariant
    > > plateaus.
    > >
    > >
    > >
    > > With best wishes,
    > > Dieter
    > >
    > >
    > > -------------------------------------------------------------------
    > > Dieter Roehrich        |
    > > Fysisk institutt       |            Email: Dieter.Rohrich@fi.uib.no
    > > Universitetet i Bergen |                        Tel:  +47-555-82722
    > > Allegt. 55             |                        Fax:  +47-555-89440
    > > N-5007 Bergen, Norway  | WWW: http://www.fi.uib.no/php/drhrich.html
    > >
    > > On Tue, 2 Jul 2002, Claus O. E. Jorgensen wrote:
    > >
    > > >
    > > > Dear Colleagues,
    > > >
    > > > Version 3.02 of the ratios paper is now ready. You can find it here:
    > > >
    > > > http://www.nbi.dk/~ekman/RatioDraft3.02.ps
    > > >
    > > > Thanks for the many comments from many of you. Much, but of
    > > course not all, has found
    > > > its way into the manuscript.
    > > >
    > > > Finally we have decided to drop the AMPT comparison. Only the K
    > > ratios do not agree so
    > > > well. The discussion takes space and the calc. will clutter the
    > > otherwise striking fig 3.
    > > > We'll save that for a later comparisonor talks.
    > > >
    > > > We are now at the point where new mods. to the text introduce
    > > new errors.
    > > > The length is also OK now.
    > > >
    > > > A careful last proof reading of numbers would be appreciated by
    > > fresh eyes. The ambition is
    > > > to submit wednesday afternoon.
    > > >
    > > > regards
    > > > Claus and JJ
    > > >
    > > >
    > >
    > >
    > >
    > >
    > 
    > 
    > 
    



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