HI Michael I agree that the wording is incorrect/inconsistent with the figure. The ordinate in fig. 5 is in fact the stated formula divided by the numbers of pairs. Alternatively the formula (with or without the factor of 2 in the first term) should refer to a fit of dN/deta, as you say. regards 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, November 21, 2001 4:41 PM Subject: Hard/soft scaling Equation is wrong > Dear Jens Jorgen, > the Hard/soft scaling equation we use is > incorrect and clearly in contradiction to Fig 5. > > > "... we fit the observed dependencies to a functional > $dN/d\eta/(N_{part}/2)=\alpha\cdot > N_{part}+\beta \cdot N_{coll}$. > For rapidities $\eta=$ 0 and 3.0 we obtain: > $\alpha=0.98 \pm 0.10$ and , $1.05 \pm 0.08$ and > $\beta=0.25 \pm 0.04, 0.09 \pm 0.03$ respectively. > > So at eta=3, beta is almost zero and this equation says that > dN/dEta * 2/Npart should grow linearly with Npart with a slope > of 1.05. However in Fig 5 we see that for eta=3. > dN/dEta * 2/Npart =~ 1.05 independent of Npart > > In Kharzee and Leven (which is now PLB {\bf B 523} 79 (2001)) > the following equation is used. > > dN Npart > -- = (1-X)*npp * ----- + X*npp *Ncoll > dEta 2 > > Thus I think that we should write > dN Npart > -- = alpha * ----- + Beta * Ncoll > dEta 2 > > I think this is what Trine fitted to. > It is also clear that the errors on alpha and beta are > anticorrelated since the total value of dN/dEta is fixed. > > Therefore I suggest that we use +- for the errors on alpha > and -+ for the errors on beta. > > The corresponding latex is > Using for $N_{coll}$ the > values estimated in ~\cite{Kharzeev_and_Nardi} we fit the observed > dependencies to a functional $dN/d\eta=\alpha\cdot > N_{part}/2+\beta \cdot N_{coll}$. For pseudorapidities $\eta=$ 0 and 3.0 we > obtain: > $\alpha=0.98 \pm 0.10$ and , $1.05 \pm 0.08$ and > $\beta=0.25 \mp 0.04, 0.09 \mp 0.03$ respectively. > For comparison we find $\alpha=0.99 \pm 0.09, 0.99 \pm 0.07, $ > and $\beta=0.18 \mp 0.04, 0.02 \mp 0.04 $ at > $\sqrt{s_{NN}}$=130 GeV. > > and the new ref [3] is > \bibitem{Kharzeev_and_Levin} D. Kharzeev and E. Levin %nucl- th/0108006 > Phys. Lett. {\bf B 523} 79 (2001), and private communication. % > > > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899 > >
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