E895 Meeting Minutes at LBNL

taken by Dieter Best

May 13th 1997

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

• GR
  • Licenses:
  • The 2 SGI machines which serve as file servers are PDSF responsibility, licenses will be extended.
  • For the other 2 machines no extension is possible.
  • There are enough licenses for 32 HP machines with HPUX10.2.
  • For additional HPs (slower) licenses are available for an older OS.
  • We will have a talk from Ron Soltz about E910 software next week.
• DB
  • residues:

    Last Friday Gulshan and I write down some questions:

    1. How do the residues look like without distortion correction? The resolution in x is 1.0 mm, in y 1.4 mm using Marvin's tracker with the track parameters in CVS.

       Using the xdev-fit and ydev-fit values from the hits table, the distribution of these quantities using the old hit finder without t0pad correction are fairly flat as a function of x and y. Calculating the residues myself from the tracks table and hits table dx-vs-x and dy-vs-y are NOT flat, for positive x and y values the mean is smaller than 0 and depends linearly on x. The reason for this is not known.

       Using the my track finder, the same old hit finder, and calculating the residues from the track parameters and hits table the residues are NOT flat as a function of x and y!

    2. How do the residues look like with distortion correction?

       The overall resolution is the same (dx=1.0mm, dy=1.4mm), but plotting xdev-fit and ydev-fit (from Marvin) as a function of x and y shows structures.

    3. How are the residues without distortion correction and no deconvolution?

       No change in the overall resolution, dx and dy also flat as function of x and y with Marvin's track finder. The number of hits/event is smaller, and the hit removal efficiency is smaller too by 10hits only. Deconvolution is necessary.

       This work has been done with tape262, file1, first couple of events.

  • track finder efficiency
    1. Showed rest point sets for both Marvin's and his track finder at 2, 4, 6, and 8AGeV data. The new track finder looks better in general, especially in the narrow cone.
    2. Shows table of efficiency values for all measured beam energies and comparison between the 2 track finders. This can be viewed on the Web:

       http://www-rnc.lbl.gov/~best/cvt_effies.html

  • Comments GR: We analyse the Au+Be data now too.
• NS: track merger
  • The track merger is now a separate module. There are 2 routines trk-join by Marvin and trk-merge by Dean. Both of them do not merge. The tracks and hits table is not updated. Recommends the use of common blocks for table reference.
• HL
  • PID module requested by Davis.
  • Efficiency corrections for protons in 6AGeV data using RQMD, showed pty plot of efficiency numbers.
  • Efficiency in some regions of phase space apparently greater than 100% due to track splitting and misidentification of positively charged pions as protons.
  • Showed efficiency corrected dN/dydmt for protons at 6AGeV.
  • Showed efficiency corrected dN/dy for protons at 6AGeV, impact parameter smaller than 4 fm.
  • Comparison with dN/dy from thermal model.
  • Showed a plot mean beta versus beam energy with our 6AGeV point and values from EOS and NA49 and from E866.
  • Showed comparison of dN/dy from EOS, E895 and NA49.
• Things to do:
  • GR: We freeze the old track finder and switch over to the new track finder. Nathan works on the track merger. Dieter, rerun the 6AGeV data with the new track finder.
  • NS: We should discuss the track and hit table format. We can make the hit table much more compact and maybe we could write dsts with hit table.
  • DB: This is what we have to discuss on the next collaboration meeting.
  • GR: We have the 2 DLS alpha machines for us to make dsts.