Dear BRAHMS friends
RHIC is requesting written proposals for beam use for the spring/summer
2001 run from the 4 experiments. The deadline is set to Nov. 10. The PAC
convenes on NOV 30.
We should thus come up with the wishes of the BRAHMS collaboration
within the given constraints (up to 33 wks of beam in FY2001).
The following is an expression of my own views at this time, to be taken
as an invitation to a hopefully collaboration-wide discussion.
1. Main priority should be given to Au+Au at full energy (100+100).
Since complete BRAHMS measurements require many field and angle settings
to cover the large acceptance,
we request that the dominant part of the beam be devoted to this. There
are many
theoretical arguments for why 100+100 is MUCH better than 65+65 (if you
believe them...).
2. It is probably a good idea to request some weeks (one meonth? of
65+65 Au+Au at high Luminosity.
Firstly, in order to be able to complete/extend the measurements taken
in 2000 and secondly to make sure that we get adequate integrated
luminosity for some measurements (one might fear that the development of
the 100+100 beam may take a long time).
3. It seems to me that we have little to gain from running other
beams-species (i.e. lighter beams) at this stage. We have apparently
adequate centrality selection and there are no obvious surprises in the
global multiplicity distribution. So there are no compelling reasons to
expect that a peripheral Au+Au is substantailly differnt from a central
lighter ion collision. Developping a new beam species would undoubtedly
take a fair amount of time.
Anyway I suspect that PHOBOS will ask for many beam species, so we
should try to reduce this.
4. In all likelyhood luminosity and duty factor will increase sharply
towards the end of the running period, as the urgency to produce results
sets in. We should therefore seriously consider in what order
measurements should be undertaken. F. ex. systematic high momentum
measurements should only be scheduled late in the period.
cheers
Jens Jorgen.
--
____________________________________________________
JENS JORGEN GAARDHOJE
Assoc. Prof. of Physics, Dr. Scient.
Niels Bohr Institute,
University of Copenhagen
Blegdamsvej 17, 2100 Copenhagen
Denmark.
Tlf: (+45) 35 32 53 09 (dir)
(+45) 35 32 52 09 (secr)
Fax: (+45) 35 32 50 16
Email: gardhoje @ nbi.dk
Home page: http://alf.nbi.dk/~gardhoje
-Chair Ph. D. School of Physics at NBI.F.AFG.
(secr. Frank Kristensen 35 32 04 41, Ørsted Lab.)
-Member Danish National Commission for UNESCO
(secr. Ulla Holm 35 32 52 72, NBI)
___________________________________________________
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