First I vote for keeping the discussion about the draft paper right
where it already is. We are a small collaboration and we should all have
the right to contribute to the physics we want to make public.
At this moment I concentrate in the first paragraph, where we state why
our measurement is so interesting:
I find that the paragraph is mainly influenced by reference 3 (Satz).
Satz paper has great clarity and is a very good summary of what was
learned at the AGS and CERN programs, but it was written just before the
first RHIC run.
I would suggest the inclusion of more recent descriptions of the
collision, or some words to explain that the measurements did not turned
out as expected. The expected "transparency" of the colliding nuclei is
not there; the pbar/p ratio is still lower than 1. We could mention the
results from HERA where
the a net proton (pbar - p)((pbar+p)/2) of 8%, eight units of rapidity
away from the incoming proton was measured in H1:
J. Stiewe Nucl. Phys. B 79 (1999) 463-465
More comments as I proceed with my reading.
Ramiro
On Monday, April 22, 2002, at 03:47 PM, Claus O. E. Jorgensen wrote:
>
> Hi all,
>
> Thanks to Michael, Radek and Steve for the comments. I've made some of
> the minor corrections you suggest, and updated to version 1.09.
> It can be found here:
>
> http://www.nbi.dk/~ekman/RatioDraft1.09.ps.gz (or)
> http://www.nbi.dk/~ekman/RatioDraft1.09.pdf.gz
>
> Enjoy!
>
> Do we want to keep this discussion on the brahms-l list? If not, where
> should we keep it then?
>
>
>
> Michael, I haven't done anything about you comments to:
>
> - how the papers underplay of the importance of the rapidity dependence.
> - weak decay corrections
> - what we can learn from the failure of HIJING and the success of AMPT?
> - description of model [3]
> - the thermal model
> - p+p and y=2 data in figure 4
> - the abstract
> - PACS
>
>
> Here's a few comments on what I have changed:
>
> - the title:
>
>> We show ratios of antihadrons/hadrons so the title is slightly
>> incorrect. Only the first word should be capitalised. For Sqrt(S_{nn})
>> I beleive the convention is to use nn rather than NN.
>
> You're right about the order of "hadrons" and "antihadrons" - it's
> fixed now. Personally I would prefer "Ratios of Charged
> Antiparticles-to-Particles...". One might think that the
> "antihadron-to-hadron ratios" are without identification of particles.
>
>
> - figure 1
>
>> For Figure 1 panels (c) and (d) why not put the symbols pi, k and p at
>> the appropriate mass**2. For panel (c) the proton peak seems to be in
>> the right place but the pion peak seems to be at negative
>> mass**2. This implies some problem with either the momentum, time or
>> length scales used to derive mass**2.
>
> I think it is too much with the pi, k and p symbols on the mass2
> plots. You're right about the negative pi mass2, I just need to redo
> the plots (and maybe the calibration). It'll be fixed.
>
>> When we use C1 to veto pions is
>> there a significant inefficency for the kaons and protons? (This is
>> the infamous Cerenkov veto effect from NA44) From panel (c) this looks
>> about 5% for the protons. Since there are usaully more e- than e+
>> around it may not be the same for antiprotons.
>
> Yes, there is a C1 misidentification factor for kaons and
> protons. This will change the pi-/pi+ ratio, but with very few percent
> (because of the small K/pi ratio). Misidentification of pions (pions
> above threshold that does not give a signal) is very close to zero, so
> the effect on the measured ratios is very small.
>
> I don't think the ratio of e-/e+ hitting C1 changes the
> misidentification from polA to polB runs. It's only the particles that
> make it through the magnetic field that can change the noise level in
> C1 from one polarity to the other. The numbers of e- and e+ can change
> slightly (but not as much as in fixed target experiments where you
> have a lot of delta-electrons), and I guess that most of these (e- and
> e+) will make nice tracks in the spectrometer and will therefore not
> lead to misidentification but inefficiency in C1. I should of course
> check this. Maybe we should put in a sentence about this, but I don't
> think we should go into too much detail.
>
>
> - figure 2
>
>> For Figure 2 I would arrange the panels as in Fig 1, ie 2 rows and 2
>> columns. For y=2 the pbar/p ratio must have a very bad Chi**2/NDF, I'd
>> guess about 6, when fit to a constant. This makes me suspect that the
>> errors are underestimated. The panels should be labeled (a), (b), (c)
>> and (d).
>
> I've tried that the 2-rows-2-columns arrangement, but I don't like it
> - the range of the x axis in plot (a) and (c) is not the same, and it
> gets a bit confusing (PRL accepts figures that span both columns). The
> data points will soon be updated and we'll hopefully get smaller error
> bars, so don't worry about the Chi**2 and missing data in plot (d) -
> it'll
> be fixed. I've made a few changes in the figure.
>
> - figure 3
>
> Scales, legends and symbols are now updated. I removed the HIJING
> prediction, and will add AMPT soon. You're right about the
> N(x-)/N(x+) notation - I've now written x-/x+ throughout the paper (and
> the first time a ratio is quoted specified that we are talking about
> "...the ratio between the number of negative and positive pions,
> pi-/pi+"). Is that clear enough? Do you really want to keep the 130
> GeV data in the plot?
>
> - figure 4
>
>> For Figure 4 why not add the 40 and 20GeV results from NA49. Also I
>> would put the labels AGS, SPS and RHIC on the top line of the box
>> around the graph. "SPS" should be properly centered. As noted above I
>> would add plots for the pp data and the ratios at y=2 or so.
>
> The numbers in figure 4 should really be checked. We should find the
> right references and add all the points we can find (any volunteers).
>
> Adding points for y=2 and for p+p would require more panels I think.
> If someone has the time to dig the numbers out of the litterature I'll
> be happy to make the plots (also as function of y/ybeam). What about
> chemical potential as function of sqrt(s_nn) at y=0 ?
>
>
> - references
>
> Are updated. I don't know how to use BIBTEX - we can change that
> later.
>
>
> - language
>
>> Paragraph 4 say "with 2sigma of the expected velocity for a given
>> moment and particle type." Put a period after "vertex distributions"
>> and start a new sentance with "Then the particle ..."
>
> The cut is not made only from 1/beta. It also takes the momentum
> resolution into account. Can we explain it more clear?
>
>
> ...Claus
>
>
> +-------------------------------------------------------------+
> | Claus Jørgensen |
> | Cand. Scient. Phone : (+45) 33 32 49 49 |
> | Cell : (+45) 27 28 49 49 |
> | Niels Bohr Institute, Ta-2, Office : (+45) 35 32 53 07 |
> | Blegdamsvej 17, DK-2100, E-mail : ekman@nbi.dk |
> | University of Copenhagen Home : www.nbi.dk/~ekman/ |
> +-------------------------------------------------------------+
>
>
>
>
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