Dear Collaborator,
I will like to add some words to the previous note send to all of you in regard to the multiplicity analysis. That note was intended to discuss where we stand, what the problems are and did not discuss how to move forward towards a scientifically sound paper. Jens Jorgen did send an e-mail to all of you on October 30 urging more communications on the matter, as well as proposing a schedule. As you have seen two notes on the subject has since appeared.
I know from discussion and comments from collaborating groups, that the analysis and a push towards a publication is considered an important goal. The question is then how do we proceed towards this goal.
Considering the proposed layout of the paper there are several unanswered questions.
a.. What is the proper way to deal with the Tile multiplicity? The bell-shape' curve extracted using the method described in detail by JH is one of two ways to perform the conversion from measured energy loss to dN/dEta. It is my understanding that S,.Sanders and Hiro Ito are close to producing a note describing the alternate method. This will enable us to judge the quality of data, as well as systematic effect
b.. The forward rapidities measurements from the Beam-Beam counters are in my opinion the most important contribution from our data to the multiplicity distributions. The analysis is though is not simple, and from discussion with Yury today there are several more investigations to be made. This in particular in regard to exploring background sources not included in the geant simulations so far. By the natures of such investigations it will take time.
If we are to have a next draft for serious discussion at the collaboration meeting action is needed i.e. other people have to step forward and be part of the process very soon and play an active role.
a.. Identify people to look at Model calculations (an important issue is what is meant by 'dn/deta'). This should be from outside the present group of people do the analysis of the data.
b.. Prepare a straw man set of figures, and work on text of paper.
c.. Prepare an unbiased view of systematic errors, and data NOT to be guided by the published data.
So in essence please step forward on comment contribute to this effort if you want it to succeed. As well please comment discuss what has been presented so far.
I envision that we will spend significant time at the meeting discussing these issues, and make a final recommendation to the collaboration how to proceed with the paper i.e. content, where to submit, and review the other preliminary data. This would include presentations on analysis, model calculations, evaluation on systematic errors, discussion of figures and text. I am coordinating the schedule with Jens Jorgen.
Lastly, I should remind you all that the overall analysis efforts clearly has multiple goal for the time being, namely i) completing the multiplicity analysis as well as can be done and ii) ensure that the particle spectra, particle ratios at mid and forward rapidities progresses and are analyzed, discussed and understood before the QM conference in mid-January. It is important that the analysis resources are used appropriately.
Best regards
Flemming
Enclosed / note from JJG dated Oct 30.
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Dear BRAHMS Friends
At the end of August we decided at the Brahms collaboration meeting that
a
paper draft for the charged particle multiplicity distribution should be
circulated to the collaboration by the end of september.
We are now approaching the end of October. A draft (without numbers) has
been written and data has been shown at several meetings (including the
DNP meeting). This must mean that we
have sufficient confidence in the data to show them publicly. The
logical next step is to publish the information.
If we do not trust the information we should not show it. In any case,
the data and method of analysis, including the various corrections must
be made available to the full collaboration for critical asessment and
for decision as to the fate and content of the publication.
I strongly feel that we must intensify the effort on this piece of very
interesting first physics from BRAHMS. I therefore urge the members of
the collaboration that have been working on the data to circulate short
up to date write-up's on the analysis, with the aim of allowing the
collaboration to evaluate the present status and decide on a course of
action.
I would propose that we set ourselves the deadline that we by the next
collaboration meeting (end of november) bring ourselves in a position to
submit a paper. I also suggest the following plan of action:
1) notes on analysis to be produced by the people analyzing the data
(JHL, YB, FV etc..)
:BY NOV 3 =END THIS WEEK
2) preparation of figure layouts (VOLUNTERRS?)
:BY NOV 10 = END OF NEXT WEEK
3) model calculations with HIJING, NEXUS, CASSINGS model etc.. vs
centrality
: BY NOV 10
4) Production of next draft and circulation to collaboration
: BY NOV 17
5) Final discussion on paper and production of final draft.
: BY NOV 24 (BRAHMS collab. meeting at BNL)
I hope that this email can start a discussion in the collaboration on
this urgent matter. Please circulate your opinions on the general list,
so that all may be informed.
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Dr. Flemming Videbaek
Physics Department
Brookhaven National Laboratory
tlf: 631-344-4106
e-mail: videbaek@bnl.gov
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