Q Dear Claus, Jens Jorgen and others,
it is lovely to see
such great data coming out from BRAHMS. Thanks
for all the work in producing the draft.
Yours Michael
In general I think the paper underplays the importance of the
rapidity dependence of the ratios.
This is not discussed in the two source model at the bottom of page 6
or in the thermal model
on page 7.
When describing the effect of weak decays say which way the
corrections would shift the ratios.
I beleive pbar/p would decrease. What can we learn from the failure
of HIGING and the sucess of
AMPT?
Page 1: The incoming baryons do not decay in flight. Rather the model
of [3] depicts a AuAu
collison at 200GeV as two thin sheet of partons that pass through
each other. This causes the
excitation of color charges which produce coherent fields between the
nuclei, somewhat
like the electric field between 2 capacitor plates. The attraction of
the charges causes the
plates to decelerate. After some time the fields decay into pairs of
quarks and gluons.
For the thermal model we have only 2 independent parameters, mu_q
and Tchem. Since
pbar/p = exp-6(Mu_q/Tchem) the fact that it decreases with rapidity
must mean that
Mu_q/Tchem increases, or Mu_q increases.
But what about Mu_s?
Taking
Similary k-/k+ = exp (-2mu_q+2mu_s)/Tchem
==> k-/k+ = (pbar/p)**1/3* exp(2Mu_s/Tchem)
and Mu_s/Tchem = 0.5 * (ln(k-/k+) - 1/3 ln (pbar/b))
At y = 0 we have Mu_s/Tchem = 0.00 +- 0.03
At y ~ 3 we have Mu_s/Tchem = 0.12 +- 0.06
Thus there is a slight tendency for Mu_s to increase with Mu_q which
is what we would expect if
the temperature stays constant.
It seems to me that nothing is made of the 2 source model . The last
sentance of this paragraph
is a tautology.
For the sqrt(S) dependence shown in Figure 4 why do we only show AuAu
and not pp? Also
why not try to study the energy dependence of the ratios at forward
rapidity. One choise would
be to compare the ratios at a constant y/ybeam. Two units from
central rapidity at RHIC is
about 1 unit away from central at SPS and so we could compare to NA44
data.
At the AGS we would want data about 0.5 units away from y=0. Flemming
do these data exist?
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.
Abstract:
We will surely work on this some more. I think that we should mention
that our pp results are close
to the AuAu ones and think of what we learn from these. I would also
mention the success of AMPT
in reproducing the results.
PACS:
Add the following number to flag the pp data.
13.85.-t Hadron-induced high- and super-high-energy interactions
(energy above 10 GeV)
Figures :
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. 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.
The horizontal scale for panels (a) and (b) should be Momentum/q
to aggree with the text.
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).
For Figure 3, please make each of the panels have the same scale, ie
the difference between
0.8 and 1.0 should be the same number of cm for each panel. Use the
same set of symbols for
pi-/pi+, k-/k+ and pbar/p as for Figures 1,2 and 4. Add the AMPT
prediction since this does a
very good job of the ratios both at RHIC and the SPS. I would not
remove the 130GeV points.
The notation of the ratios in Figure 3 is very ugly. Trying to read
N(K-)/N(K+) at 90 degrees is hard.
Why not just put pi-/pi+, K-/K+ and pbar/p horizontally This would be
much clearer both here and
in the text. (Look at the legend in Figure 4). It seems to me that
this is also the place to show the pp data.
By the way the 3 panels should be labeled (a), (b) and (c). Remove
"BRAHMS Preliminary". Also you
should not in the caption that the SPS data is for PbPb.
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.
For all the figures all labels should have the same precision.
Therefore you should change
"0.8 1 1.2" to "0.8 1.0 1.2". Generally avoid writing at 90 degrees
since it is harder to read than
text that is horizontal.
References:
These are slightly out of order. Physical Review prefers that we use
BIBTEX since it makes it
easier for them to "havest" the references and insert hyperlinks in the
electronic version of the
paper. Also it is simpler ti control the format of the references. For
us it means that we don't have
to worry about
ordering the references, or fomating them (italizing "Et Al" etc)
and we can use the same bibtex file for all our papers. We just keep
adding
new references as we need them. Latex then keeps track of which ones we
use.
If you wish I can make this. At the moment you make the first
citation of references in the following order
1,2,3, 6,7, 8,11,9,10, 4,5,6, 12,13, 15
Ref [3] is
I. N. Mishustin and J. I. Kapusta Phys. Rev. Lett. 88,
112501 (2002).
Ref [7] is
B. B. Back et al. Phys. Rev Lett. 88, 022302 (2002)
Ref [12] is nucl-ex/0203016 put C. Adler before STAR Collaboration
Ref [2] is W.A. Zajc and PHENIX Collaboration, Nucl Phys A698 39c
(2002).
Ref [4] say " `Conceptual " , ie use open quote.
Please cite the ZDC NIM paper at the top of page 5, it is
C. Adler, A. Denisov, E. Garcia, M. Murray, H. Strobele and S. White
Nucl.Instrum.Meth. A470 (2001) 488-499
We should make the numbers easily available so that we have a bigger
impact.
For the STAR HBT paper nucl-ex/0107008 they point to a URL with the data
in their abstract
at the LANL preprint server.
Title: Pion Interferometry of $\sqrt{s_{NN}} = 130$ GeV Au+Au Collisions at
RHIC
Authors: STAR Collaboration: C. Adler, et al
Comments: 6 pages, 3 figures; accepted to Phys Rev Lett; data tables
available at STAR web site this http
URL Click on "Publications" in menu bar
We should make our data publically avaible both by having links in the
publication to our web site and
by submitting it to EPAPS.
Language:
I really think that N(K-)/N(K+) is much less clear than K-/K+. Throughout
the text "Figure" is used even
when it is not the first word in a sentance. "Physical Review" prefers
"Fig." accept at the begining of
a sentance.
On page 3 I think CM energy of 39.4TeV is less precise than
Sqrt(S_nn)=200GeV since we do not
know that all the nucleons take part in the collision.
2nd paragraph
1st line say "we present THE first measurements"
Is it really necessary to talk about the ratios of charged mesons, hadrons
and baryons? Why not just say that
we study the ratios or antiparticles and particles.
I would define rapidity as tanh-1 (beta_z). While you are doing this should
you not also define
pseudo-rapidity and p_T which you use in the paper?
Page 4
Line 3 change pi+/pi- to pi-/pi+.
2nd paragraph, 1st line. Change "light mesons" to "pions"
3rd paragraph: The MRS does not cover 30^0 < theta < 90^o. Rather it can be
rotated
between these angles. The same is true for the FRS. Use the term "polar
angle"
Don't define acronyms that you don't use later, eg TPCs, PID, FFS, BFS, IR
and TOFW.
Page 5:
Line 1 use " `minimum " instead of " 'minimium "
Line 3 reference the ZDC Nim paper
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 ..."
Last paragraph. Put a period after 40 degrees.
Last sentance change "For Kaons" to "For kaons" and change K- to K^- .
Page 6
1st line. Replace "shown experimental ratios" by "data"
Paragraph 1 change p_t by p_T throughout the text and figures.
Move the sentance about the centrality bias to just after the description of
the spectrometers.
Last line change "In the following quote" to "In the following WE quote"
Why do we say y~0. Don't we mean y=0?
Page 7 You derive nothing from the 2 source model. The llast line of
paragpaph 1 is a tautology.
Don't start a sentance with a symbol. Instead of "T=174" say "The
temperature T="
Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899
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