E895 Meeting Minutes at LBNL

taken by Dieter Best

May 7th 1997

• Attending: Gulshan Rai (GR), Nathan Stone (NS), Dieter Best (DB), Heng Liu (HL), James Symons (JS)

• GR
  • HL has a talk on NN97
  • DB has a poster on NN97
  • Bao-An Li has a talk on NN97 and contacted us
  • Tom Hemmik contacted us and needs something for the AGS user meeting
  • the reply to the announcement of the E895 collaboration meeting was mostly positive. The E895 Collaboration Meeting is June 7th and 8th at The Ohio State University, Mike Lisa has been informed and he starts to make arrangements. Half a day might be devoted to EOS related topics.
  • GR goes to New Zealand on June 1 for 4 weeks, he will return June 28. Hand Georg Ritter will be in charge of the group during this time.
• DB
  • Jeff Porter told me, the license for the 4 4-processor SGI machines of PDSF runs out this month. 2 of them are file servers, the other 2 compute machines and not yet up. We have to take actions in order to make sure that we get an extension.
  • Jeff Porter told me too, the license for the 2 E895 10 slot ExaByte stackers on PDSF runs out June 8th. We have a temporary license for 3 months only. An extension is no problem, but we have to decide whether we want the stackers on those 2 SUNs, if we want to move them, we have to pay.
  • The agreement among the members of this groups is: make sure we get the extension, and we do not move the stackers. GR will try to make sure that we will get the SGI licenses.
• HL
  • shows drift velocity versus run number, the drift velocity has been obtained via the edge finding method. Comparison with earlier results from Jerry Chance for EOS data shows that the values are not totally unreasonable. The method is established and can be performed routinely.
  • Comment by GR: Can this be done by a summer student? - I will look into this option.
  • HL shows newer dN/dy for protons at 6AGeV, dN/dy at midrapidity is 30 for central events with impact parameter b<3fm. This data is compared to the prediction of a thermal model with a continuous distribution of fire balls within a certain rapidity range. This results is not yet efficiency corrected, efficiency studies using the fast simulator and already generated RQMD2.3 output are under way.
  • comments/questions by DB: What is the longitudinal flow velocity? - What is the centrality? - How is centrality determined?

• NS
  • Changes on 2D hit finder from Mike Lisa and changes on 1D from Chris Pinkenburg included in CVS.
  • the 2D hit finder runs on the SUNs of PDSF but NOT on the HPs.
  • a number of other small changes have been done to the CVS code.
  • application of t0pad and gain correction not yet possible in the hit finders we have here, but is in Chris's version of the 1D hit finder.
  • Comments/questions by GR: The t0pad and gain corrections are OK according to Mike Lisa. He worried about the bad pad table. Heng was supposed to look into this. Heng? - Negative. Heng and Nathan work together and get to the bottom of this.
• DB
  • Update on resolution studies (several plots, Marvin's track finder): The spatial resolution is 1 mm in x and 1.4 mm in y, the distributions as a function of x and y are reasonably flat in our environment. The old hit finder has been used with NO t0pad calibration (= all t0pad values are 0). The results agree for 2 and 6 AGeV data. There is a dependency in dy-vs-y on the padrow number which is unexplained.
  • several plots comparing Justice track finder (JTF) and Best track finder (BTF), BTF has:
    • smaller rest point set, hit removal efficiency is 80% as compared to 70% for JTF.
    • finds about a factor of 2 less tracks than JTF.
    • higher mean number of hits/track (50 as opposed to 35).
  • showed the principal of operation for BTF (Kalman filter), which is the same for JTF.
  • showed call tree for BTF
  • showed parameter file (16 parameters).
  • Question: Should we freeze the status of the old track finder and go with the new track finder?
  • Comments/questions:
    • NS: We need more evaluation first, we need to go through a similar procedure as with the 2D hit finder.
    • HL: How does the residue distribution look like for BTF?
    • NS: Is refitting with the main interaction vertex done?
    • DB: No 2. pass is implemented yet, no dE/dx and no refitting with the primary vertex. Things to be done: Need a track switch table. More evaluation certainly necessary.
  • What about the Fast Simulator?
  • Comment HL: I am right now working on making the Fast Simulator reproducing the experimental resolution and appropriate acceptance and efficiency studies using RQMD2.3.