From: Fouad Rami (Fouad.Rami@IReS.in2p3.fr)
Date: Mon Jun 30 2003 - 11:13:08 EDT
Hi all, The present draft version (June 29) looks very good. I have only 2 comments concerning Fig.3: 1) Last paragraph, page 4 -> "The figure shows that, within errors, the degree of high-pt suppression (at pt > 2GeV/c) observed at eta=2 is similar or larger than at eta=0". I don't like "similar" in this sentence. Fig.3 shows clearly stronger suppression at eta=2 in the high pt region (pt > 2GeV/c); it is not "similar". Look at the figure, all 3 points above 2GeV/c are significantly lower, within error bars, than the value at low pt. At pt~3GeV/c, there is almost a factor of 2. I don't know what this could mean in terms of physics (rather unexpected!), but this is what the data in Fig.3 are telling us and those data are free from systematic uncertainties! I think that this effect should be stated clearly in the paper and not just as "similar or larger". It is larger ... 2) The second comment is rather a question to Claus and the high-pt team. Can we say something on the y-dependence of the high pt suppression from the R_AA ratio (Fig.2), by comparing for example the right/left panels in the upper part (central events) of the figure ? Is it consistent with what we observe in Fig.3 ? If this is the case, then we should mention it in the manuscript. This would strengthen the message in the paper: same effect observed consistently from the analysis of 2 different observables (R_AA and R_cp). I know that because of the lack of p+p reference at eta=2, the R_AA ratio at eta=2 is somewhat model-dependent (it relies on Hijing) and it is therefore subjected to much larger systematic uncertainties etc. Nervertheless, if we show R_AA at both rapidities (eta=0 and 2), then it is legitimate to ask whether the ratio R_AA(eta=2)/R_AA(eta=0) is consistent with the trend observed in Fig.3 ? Best regards, Fouad ----------------------------------------------------------------------- Fouad RAMI e-mail: fouad.rami@ires.in2p3.fr IReS phone : 33.(0)3.88.10.62.00 23,rue du Loess : 33.(0)3.88.10.64.55 B.P.28-BAT.20 (secretary's office) 67037 Strasbourg Cedex 2 fax : 33.(0)3.88.10.66.14 France -----------------------------------------------------------------------
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