Dear Bjorn,
the KLM collaboration has studied PbPb collisions
at the SPS with Emulsion. They are ref [17] of our 200GeV paper.
In figure 2 of PRC 62 014903 they plot the multiplicity per
wounded nucleon W. They have dN/deta/W = .93 at eta=0 and
in Table 2 list W=2*(170+-7). This gives dN/deta=316+-20 at
at eta=0 for 10% central PbPb collisions. They say that they
are consistent with another emulsion experiment EMU02
PLB 407 92 (1997).
Yours Michael
Quoting Bjorn H Samset <bjornhs@rcf2.rhic.bnl.gov>:
> On Sat, 1 Dec 2001, Hironori Ito wrote:
>
> > Hello. For appetizer of some people, dndeta for 0-5 % central
> > 22 Gev run is about 200 at eta=0 by silicon and tile. A normalization
> is
> > done using Hijing to estimate BB counter (trigger 1) efficiency. (We
> > know it is way model dependent.) The number (200) seems to be too
> > low. Unless someone comes up with better (or right) normalization,
> this is
> > it for 22 Gev run.
>
> ...and TPM1 can (almost)confirm this. Using the same simple
> normalization
> I get
>
> dNdEta ~ 210
>
> at eta=0. However: Comparing the BB multiplicity distribution from
> geant
> with data indicates that assuming a very high efficiency at 0-5% may
> not
> be correct (the nose of the "min"bias is very round), so a better
> normalization may well increase this number. (I.e. we need to properly
> digitize the BB response - I haven't managed to do this yet.) Also the
> vertex distribution I have used in my simulation isn't quite as flat as
> the data sample.
>
> On Sun, 2 Dec 2001, Michael Murray wrote:
>
> > Another approach is to calculate the average
> > dN/dEta for the 100 highest multplicity events.
> > Then you don't have to worry about any efficences.
>
> This (luckily) is easy - for my top 100 events (using BB mult) I get
>
> dNdEta ~ 260
>
> Somewhat higher (I might add that the 0-5% sample above was ~2700
> events)
> - what dNdEta do we expect for this energy?
>
> I'll hack away at this some more and send more details as I go along.
>
> Ping :-)
>
>
> --
> Bjorn H. Samset Phone: 22856465/92051998
> PhD student, heavy ion physics Adr: Schouterrassen 6
> Inst. of Physics, University of Oslo 0573 Oslo
> \|/
> ----------------------------> -*- <-----------------------------
> /|\
>
Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899
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