Hi Michael, Indeed the main reason for the upwards shift in the 200/130 spectra is prob. due to a broadening of the central plateau and thus amismatch of the rapidity. Thus I favor, as previously suggested, that we in the paper plot the ratio vs. Npart. The information vs eta is contained in the other plots (at least for selected points) . It seems to me that in view of obvious space limitations this plot is perhaps the least interesting (?). Opinions? cheers JJ ________________________________ Jens Jørgen Gaardhøje Assoc. prof. Dr. Scient. Chair Ph.D: school of Physics NBI.f.AFG. (secretariat. 35 32 04 41) Chair science committee. UNESCO Natl. Commission. (secretariat. 33 92 52 16) Office: Niels Bohr Institute, Blegdamsvej 17, 2100, Copenhagen, Denmark. Tlf: (+45) 35 32 53 09 Fax: (+45) 35 32 50 16 ________________________________ ----- Original Message ----- From: "Michael Murray" <murray@cyclotronmail.tamu.edu> To: <brahms-l@bnl.gov> Sent: Wednesday, October 24, 2001 4:03 PM Subject: Re: Draft multiplicity paper. BRAHMS 200AGeV. > Dear Steve, > when comparing dN/dEta distributions from > different energies should > we compare them at the same rapidity or the same > rapidity/(beam rapidity)? > Yours Michael > > > Quoting "Stephen J. Sanders" <ssanders@ku.edu>: > > > Hi, > > As JJ has indicated, the 200 mult paper running on a fast track and we > > > > hope to have a > > final version by the time JJ gets back (JJ is the principal author of > > the current > > draft). While undergoing the hardship of a meeting > > in Mali (Hawaii), I did have a chance to chat with Kharzeev concerning > > his > > calculations and the overall question of model comparisons. He brought > > up > > several points, in particular, that we need to consider for the "next" > > draft: > > 1) The Hijing Npart numbers are known to differ from the Glauber values > > for > > more peripheral events. The reason for this discrepancy is apparently > > not well > > understood, since Hijing uses Glauber to calculate these numbers. In > > any case, Phobos, > > Phenex, and Kharzeev now all have the same Npart numbers based on > > Glauber. > > The clear suggestion is that we also adopt the newer (correct?) > > numbers. > > 2) For central collisions, Npart is modified (increased) due to quantum > > > > fluctuation. > > This increase is NOT accounted for in the present calculations and, > > therefore, > > when the theory curve shows a "flat" dependence of 2*(dN/deta)/Npart vs. > > > > Npart for > > central events, the data are expected to rise as Npart increases because > > > > of the > > fluctuations. (Motto, theorists are crafty...). This suggests to me > > that an attempt > > to fit a functional form like A*Npart + B*Ncol may not be very useful. > > 3) Both Kharzeev and Wang have suggested that what IS useful is the > > ratio > > of the 200/130 (dN/deta)/Npart results. Here we can expect scaling > > errors of the > > experiment and some inadequacies of the theory (such as fluctuation) to > > > > partially cancel. > > Hiro is working on this figure now and we expect a new draft with the > > revised figures > > by mid-week. > > > > While moving the discussion of the draft from the paper committee to > > the > > "committee of the whole" is undoubtly burdensome, the hope is that > > getting > > feedback early will speed up the final submission. These results are > > clearly > > of great interest to the community. (...and, we are not the only group > > that has > > done this measurement...) > > > > Regards, Steve > > > > > > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899 > >
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