[Fwd: [Fwd: INVITATION TO START THINKING ABOUT RUN PLANS for BRAHMS]]

From: Betty McBreen (mcbreen@sgs1.hirg.bnl.gov)
Date: Fri Jun 30 2000 - 14:05:00 EDT

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-- 
Betty McBreen E-MAIL mcbreen@bnl.gov PHONE 631-344-5111  FAX
631-344-1334

attached mail follows:

> Dear Betty Somwhow the message to the general Brahms list bounced agian. Could you send it for me to all? thanks JJ > Dear Brahms collaborators. > > Flemming and I have decided that the time has now come to start the > discussion on a run plan for the summer. This discussion should take > place over the BRAHMS general list so that all can take part in it and > voice their oinions. The ambition is to work out a reasonably detailed > 'shopping' list for the things we would like to do over the summer, so > that we can both debug the experiment and collect useful physics. > > There may be different views on how to proceed, all subject to the > machine performs and what the luminosity turns out to be. We may have to > develop a tree-like run plan to account for different machine scenarios. > > To give a flavour of the very first exchanges on these issue between > Flemming and me I enclose a few > 'clips'. > > Best regards > > JJ and flemming > > ******************** JJG on 26-6 ******************** > I guess we should also start thinking about a detailed run plan in the > case that RHIC operations move in a stable mode and the experiments > begin to move into the physics mode. > > This is probably not so difficult, but it may be usefull to work out a > rather detailed list already now. There may be input on items that could > > end up being forgotten. > > I could imagine the following to open the discussion: > > MRS at 90 deg: measure at field settings to cover the pt=p range from > few 0.1 Gev to >1.5 GeV. > Record data with both polarities. > Calibration of time spectra should be done by comparing various > settings. We should be careful that the range coveres is large enough to > > see heavy clusters (e.g. d, anti-d, t, anti-t. etc..). > Perhaps one should, depending on background conditions, make provisions > for a TOF trigger (gates must be large enough for accepting slow moving > heavy particles). > > FFS at some low angle. Your suggestion of 3-5 deg seems right if the > background is OK. Here we must again have enough settings to cover a > reasonably nice Y slice around the interesting (low) pt range. Cover > both polarities. Again a spec. trigger should be considered. > > All data in coincidence with ZDC, BB. Tiles and Si prob. also in > trigger with no restrictions. > As far as ZDC and BB goes we should explore the influence of the mult. > requirement on the BB. I guess there are no hard cuts on the ZDC > spectrum. > > This would allow us to hopefully get first data on pi, K and p leading > to some ratios in the two rapidity intervals and some rough spectrum > slopes. Coalescence should be fairly easy (roughy same number of d and > d-bar expected): the number of baryons produced goes up , but the > number of d/p**2 probably(hopefully) goes down. A good statistics run > for pions at MRS would also be good for HBT (>30k pairs). > > We should also consider moving both spectrometers to the same angle > (e.g. 30 deg.) if the count rate perimits before the end of the run, so > that we may start to compare rates etc... > > Cheers > JJ > > ********************************************** > > ************* part of Flemmings ansver (translated from > Danish)****************** > Hi Jens Jorgen, > > .... > I agree that we should discuss run plans more. You will find that my > original draft is somewhat different from yours. I would tend more > towards several measurements at different angles (f.ex 90, 60, 40 deg) > and a few at the forward settings (FS) and focus on good pion, kaon, > proton spectra and save the rarer event for later. This is mostly to > have shorter runs (more stable conditions) and save the orther for > peiods where the luminosity (and the triggers) are bedre. > > We know pretty well what running times are needed for single partikle > spectra as a function of luminosity and triggers. Could you come up with > estimates of your rate/setting estimates for d, d,d-bar f.ex. at 90 deg, > and 10,5 deg. > > ... > Flemming > > ************************** > > *************reply from JJ**************** > > >From our SPS data we know that we collected 24 anti -d over 96 hrs of > running. These were for 20% central events with a spec trigger. There > was probably about 400.000 raw single particle events recorded for this > (av. rate of 400 evts/sec). > > For RHIC at 1 central ev/sek we should in 40 hrs get 160.000 central > coll. With the solid angle that we have . and perhaps assuming that the > antibaryon prod. rate is larger than at SPS by a factor of 10. We could > land on more or less the same number. At the same time we would collect > masses of , K- and p-bars. > > At SPS (NA44) the d/p ratio is 0.017 at midrap. We should again expect > several hundred deut. in say 40 hrs in a setting that will also allow > collection of pi+,K+,p in large numbers (MRS). > > So I would think that d and perhaps d-bar is very feasible initially > with somewhat longer runs at the same setting. In general I like the > idea of having a few very good data sets with high statistics also for > debugging the analysis details. > > Cheers JJ > > ************** > > Anyway, this is the spirit of the discussion, so PLEASE JOIN IN; > BRAHMS'ERS!!! > > CHEERS > > JJ and F > > -- > ____________________________________________________ > 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) > ___________________________________________________ -- ____________________________________________________ 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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