Hi peter, thanks for your comments - ionut has to answer some of these , but I can offer a bit of insight on some of the analysis.- -One of the problems in the low energy runs are they do not have the same kind of coverage as the higher energy i.e. both A/B polarity. We know this is a potential problem; I in fact do not use smaller bins at y~0 in the pp analysis for that same reason. The difference in yield is realy driven by the very lowest pt bins , and having only 5% differences when covering 70% of the yield is quite an accomplishment. The difference, or rather non difference to y=1 is driven in my opinion by the less pt coverage that we have. I see a fairly flat at 200 GeV (the run-4 data) where we did not have low pt coverage, since there was a push to do high pt- which could not really do anyhow. One way out of this for pions is to do a simultaneous fit to all the settings from 0-1 in y i.e. with a fixed or slowly varying <pt> and then check the yields. Your suggestion to look at the integrated yield over the same pt range at y=0 and y=1 is a good on! On the Landau, I actually think the near final result from pion at 200 GeV which has a 30% increase at y~3 when fit with power law as Djam did will NOT we described by a Landau either in the previous Gaussian approximation or the newer Wong inspired functional form. On the pbar/p this is one of Chellis comments that will surely be addressed. On the other questions this this should be addressed - Flemming On Mar 13, 2009, at 9:21 AM, Peter Christiansen wrote: > Hi, > > I did not have time yet to read the full paper in detail, but I have > some > general comments on some parts (particularly the data). > > If I sound a bit sour then add a few smileys:-) I know that this > represents a great amount of work! However, I feel that with a small > effort on the data part (and a little work on the text) this could > be a > really great paper! > > So here I go:-) > > The quality of the data is not impressive. y=-0.1 and y=0.1 gives > quite > large differences: 202 vs 215 and 208 vs 216. As this is where we > have the > easiest analysis it is a bit worrisome. > > In general the dN/dy trend between 0 and 1 is at best flat, but more > looks > rising?!. I would appreciate to see the data points for the integrated > yields (no fits!), i.e., from pT 0.35-1.8 for pions where there is > coverage for all 4 data points. (and the same for Kaons:0.35-1.90). If > that shows the same trend, then ok..... One could also as an > additional > check overlay the spectra (Ian's idea). > My personal feeling is looking at fig1 that the two low pT data > points at > y~0 is much below the fit. > > This is important for my main point which is that it is a bit sad > for me > that there is no follow up on the Landau story which I like, but ok, > the > Gauss fit is not so good if dN/dy(y=0) <= dN/dy(y=1). > Should the provoking conclusion be: pion dN/dy is Gaussian at SPS/ > AGS and > RHIC maximum energy but not at 62 Gev? > > How can URQMD give any meaningful contribution to the ratio discussion > after you killed it in Fig. 2? I agree that the trends in Fig. 4 is > much > better, but then you should perhaps rescale the URQMD pions? > > A lot of times the p/p-bar is used, but no reference is given (as > far as I > can see). > > Table 1 and 2. Could we have the y-range. F.R. is for what fits? > (there is > quite a large difference between power law and mt). Maybe we should > just > give the yields in the pT-range. > Is the point at 3.32 meaningful to include? 8% coverage! > In general I would reduced the numbers to e.g. 202+-3 > > Summary: > which is understood -> which is not understood. Seriously! > > What is the main message of this paper? IMO it should be that the > particle > ratios exhibits a universal behavior from SPS top energies to RHIC top > energies as a function of p-bar/p e.g. figure 5 and 6. While this > can be > partly understood in the statistical model with a constant T (why do > we > not compare to those models, e.g. therminator/Michael Murray) the > rapidity > dependence can only be understood if we have local equilibration in > y i.e. > the particle production at rapidity y is dominated by the chemical > potential at rapidity y. > > Not only does the event generators fail to describe the specific > energy > dependence, but: > a) AMPT shows no universal behavior (figure 6) > b) the associated production of K+ relative to pi+ at large baryon > chemical potentials (low p-bar/p) has the opposite behavior in both > models > as in the data (figure 5) > > My prioritized wish list:-) > 1) Data consistency check at y=0 and y=0+1 > 2) Add a Gaussian fit to figure 2 and mention Landau > 3) Update summary > 4) Add the therminator/statistical model curves on the plots > > Cheers, > Peter > > > > On Fri, March 6, 2009 1:16 pm, flemming videbaek wrote: >> >> >> >> Dear Collaborator, >> >> The paper "\title{Kaon and pion production in central Au+Au >> collisions >> at $\sqrt{s_{NN}}=62.4$~GeV} has been prepared by Ionut Arsene, >> and reviewed discussed among a fairly large group including the >> committee members JH, Pawel, Dieter, Trine. It has also been >> discussed >> extensively in the >> weekly analysis meeting. The paper is intended to be submitted to >> Physics Letters B. >> It is now ready for collaboration review; I would appreciate comments >> within the next two weeks with a deadline of Friday March 20. >> Hopefully it can be submitted before QM 2008. >> >> >> best regards >> Flemming >> >> >> >> >> Flemming videbaek >> videbaek @ bnl.gov >> Brookhaven National Lab >> 631-344-4106 >> cell: 631-681-1596 >> >> >> >> _______________________________________________ >> Brahms-l mailing list >> Brahms-l_at_lists.bnl.gov >> https://lists.bnl.gov/mailman/listinfo/brahms-l >> > > > -- > Peter Christiansen > Email: peter.christiansen_at_hep.lu.se > Phone: (+46) 046-2227709 > > Address: > Lund University > Department of Physics > Div. of Experimental High-Energy Physics > Box 118 > SE-221 00 Lund > Sweden Flemming videbaek videbaek @ bnl.gov Brookhaven National Lab 631-344-4106 cell: 631-681-1596 _______________________________________________ Brahms-l mailing list Brahms-l_at_lists.bnl.gov https://lists.bnl.gov/mailman/listinfo/brahms-lReceived on Sat Mar 14 2009 - 19:06:04 EDT
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