Re: [Brahms-l] Minutes 16 Feb 07

Hi
I added a few comments marked by "<<<" to this agenda.
regards
    Flemming




> Minutes of BRAHMS Analysis meeting Friday 16 March 2007
> =======================================================
> Submitted by Michael Murray
>
> http://indico.cern.ch/conferenceDisplay.py?confId=13684
>
>
> Present: JH, Flemming, Ramiro, Hongyan, Steve, Selemon, Dipali,
> Pawel, Catalin and Michael
>
>
>
> Action Item:
> 1) Tell Europeans that US has moved to daylight savings time. Until
> the end of March there is only 5 hour difference between BNL and Europe
> 2) Calibrate Zdc vertex for dAu runs
<<< Only if this turns out to be needed. Check. For some Runs Ramiro was already happy

>
> 3) JH to work with Hongyan on dAu normalization
> This has already started. JH sent out a procedure that is listed
> below and Hongyan will try it.
> 4) Catalin: For AuAu at 200GeV Check efficiency of TPCs.
> 5) Catalin: Do momentum correction at high Pt.
>
> Agenda
> 09:30 pp at 62 GeV Flemming Videbaek
> Update on analysis of 62 gev spectra
> 10:00 STAR dAu paper discussion Ramiro Debbe
> A couple of figures to get the discussion going
> 10:20 AuAu 200 GeV analysis Catalin Ristea (NBI)
> Update on the mrs analysis for this time.
> 10:40 a few updates on dAu Hongyan Yang
> normalization method update for runs with cross talk
>
> ------------------------------------------------------------------------ 
> -
> Flemming Update on analysis of pp 62 Gev spectra
> His Analysis note is now posted as documents in todays agenda, please
> read and comment.
>
> • Data used (detailed list of runs ...)
> • Analysis Method
> • Selection and Cuts
> • PID: TFW2 in MRS, RICH in FS, H2 in FS (4,6 degree low field).
> • Corrections Histograms
> • Trigger biases,  Data yields
> • Spectrum generation• Quality Control
> • Comparison to ISR data
>
> For the paper he plans to show minimum bias  spectra y~0, y~1 y~2.5,
> y~3.
> –Pion, kaon, proton and compare to ISR. There will be figures of
> K/p, k/pi Pi+/pi- ratios as well as
> H+,h-spectra. He would like to compare to pythia and  pQCD and look at
> Limiting fragmentation for spectra pi,K..
<<< After meeting Chellis proposed that maybe this comparison should be in a seperate paper. This may
make sense, since this would also involve other ISR data (energies) to make the better matching.
This could then make a letter (PLB) rather than the PRD envisioned for our 62 GeV data.

>
> ========================================================================
> ===========
> Ramiro, d-Au Centrality:
> STAR Uses TPC for centrality determination,  while Phobos using the
> forward rings, which they claim are less biased. We have to use
> charged multiplicity for |eta|<2.2 and we should discuss in our paper
> what effect this causes.
>
>
> =====================================================
>
> Hongyan Yang, dAu update:
> For 90 degrees half field Hongyan has compared spectra where she uses
> 3 different detectors for normalization and vertex detection.
>
>
> JH We should not select tracks with ZDC vertex, rather use vertex
> from tracks. For normalization count min bias events for a given
> vertex range. For a given vertex window count number of ZDC events
> with that vertices in that vertex bin and then correct with INEL/ZDC
> to correct for limited acceptance of ZDC.
>
> Steve for events where all 3 detectors have vertices do we have
> detectors have consistent vertices? Ramiro says yes for INEL and BB.
>
> BB/INEL is the same, ~1.5, for all different particles.
> Action Item: Check ZDC vertex calibration
>
> Normalisation
>
> 1. For runs outside run range [8076, 8306], using INEL
> 2. In range [8076, 8306], using BB vertex to select event, and
> rescaled BB events to do normalization
> Finally, spectra are constructed by the combination of these two set
> of data
>
>
> Catylyn and JH: Scaling of spectra should be done from ratio of min-
> bias vertices, not from spectra.
>
> Action Item: JH and Hongyan will work on normalization.
>
> This was done a few hours after the meeting. JH suggested the
> following procedure.
>
> 0. Before you tried to use ZDC/Trigger4 for the normalization,
> check the calibration as Steve suggested.  Look at   "|ZDC vtx - MRS
> Vtx| vs. run number".
>
> 1. Make ratios of (For a vertex bin 0-5cm for an example)
>        N5         N(Exclusive Trigger5 with 0< INEL vertex <5cm)
> *scaledown5
> R=   ----    =
> ------------------------------------------------------------------------ 
> -----------
>        N4         N(Exclusive Trigger4 with 0< ZDC vertex < 5cm)
> *scaledown4
>
> 2. Check "R vs run number", and see if it's flat. If not we might
> have a problem of using
> ZDC for the normalization.
>
> 3. Build spectra using Track Vertex and Spec Trigger
>
> 4. Now calculate the final yields    - A: using N5 as you normally do
>    - B: using  N4*R  instead of using N5
>
> 5. See if you can get consistent results from A and B
>
> 5. If the results are consistent, you can extend the method for the
> runs where we have a problem
> with INEL trigger.
>
> There will be no loss of statistics since the spectra come from  Spec
> trigger and with vertecies  from tracks. However requiring a ZDC (or
> BB) vertex, would mean the data were not minimum-bias.
>
> Hongyan agreed to try this.
>
>
> AuAu 200 GeV analysis Catalin Ristea:
> Update on the mrs analysis for this time, FS in a couple of weeks.
> He switched over to the standard BanApp analysis and this cost hims
> some time.
>
> Vertex selection:
> [-15, 15] cm
> 4 sigma cuts around the vertex offsets
> Using banapp
> Acceptance maps
> 5 cm vertex bins
> 0.5 edges cuts
> slat range 32 – 113 in Tofw
> slat range 3 – 41 in Tfw2
> 3 sigma pid in m2p, using dead slat
>
> He compares his old method (build spectrum by filling a certain bin
> in Pt
> and then doing all corrections) and 2d method (y,pt) and then
> projecting on to Pt axis. They agree fairly well.
>
> He has an issue with acceptance maps and finds he needs a cut on
> TPM2. Flemming remember that their was some problem with TPC FEE
> cards in AuAu.
> Action Item: Check efficiency of TPCs.

<<< I went back to presentations form 2004 -also shown at the Kansas coll meeting which had already observed this problem
in TPM2. I believe (Ramiro check) that we changed FEE cards before the 2005 run and is thus not seen later.


>
> He finds a PID efficiency of about 98% after he ignores sick slats.
>
> He makes the ratio of identified particles to charged particles.
>
> He also compares to STAR and finds we are closer to them than PHENIX is
> Action item: Do momentum correction at high Pt. To be consistent with
> PHENIX he has to leave off any corrections.
>
> He has also compared identified particles to PHENIX and STAR.
> The agreement is better with STAR and than with PHENIX.
> Please see his slides.
>
> The meeting had to close at 11am BNL time.
>
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