Radphi Video Conference June 14, 2004

June 14, 2004
University of Connecticut
Storrs, CT

Meeting Agenda:

1. Finishing touches for the NIM article
2. Author list for the NIM article (I will prepare a draft in advance for the meeting)
3. Improvements to the LGD clusterizer (Mihajlo Kornicer)
4. BGV calibration and mass resolution (Dan Steiner)
5. First physics topics (Richard Jones, S. Teige)

• http://dustbunny.physics.indiana.edu/~teige/nim
• http://zeus.phys.uconn.edu/radphi/call-notes
• http://dustbunny.physics.indiana.edu/~dkrop/kinefit
• http://cabibbo.physics.wm.edu/~steiner/radphi/
• http://zeus.phys.uconn.edu/radphi/signals-12-2003

Present: R. Jones, S. Teige, D. Steiner, M. Kornicer, P. Rubin, E. Smith, C. Steffen, D. Sober

• At the above link on Scott's web site, he has posted the latest draft of the NIM article. Responses containing suggested changes have come in from Elton, Dan Steiner, Craig, Richard, Dan Sober, Hall Crannell, Jim Kolata, and possibly others. Scott is in the process of merging the changes into the document, which he plans to complete within the next day or so. When this is done he will post the resulting article in pdf format on the same web site, and send around a link in an email to the rad_phi@jlab.org mailing list.
• Everyone on the call was polled for their opinion on the status of the paper and the unanimous view was that the present content, with suggested clarifications, is sufficient and ready for publication.
• In view of the substantial number of suggested changes that Scott received, it was agreed that the next draft needs to be carefully gone over by two or three people for final checks before it goes out the door. Volunteers to do the final editing pass are Phil Rubin, Dan Sober, and Richard Jones. Assuming that the document is in reasonable shape following the first round of edits, two or three days should be sufficient for the gang of three to certify a final edition, starting from the time that Scott sends out his email with the revised draft. During that time, input from anyone in the collaboration is invited who would be willing to make a final pass through the paper.

My recollection of the definition of the coordinate system is as follows:
• +Z is the direction of the beam momentum
• +Y is up
• +X is beam left
• X=Y=0 is center of the beam, and center of the target
• Z=0 is the upstream face of the target.

The following author list emerged at the end of the meeting, after suggested changes were merged with the original list:
• Indiana University:
  • A. Dzierba
  • S. Teige
  • C. Steffen
  • D. Rust
  • R. Gardner
  • J. Gunter
  • R. Lindenbush
  • D. Krop
  • P. Smith
  • E. Scott
• College of William and Mary:
  • D. Armstrong
  • D.J. Steiner
  • L.J. Kaufman (now at Jefferson Lab, Newport News, VA)
  • J. Roche (now at Jefferson Lab, Newport News, VA)
  • E. Koskinen
  • J. Knowles
• University of Virginia:
  • D. Pocanic
  • E. Frlez
• University of Notre Dame:
  • J. Kolata
  • L. Lamm
  • G. Rogachev
• University of Connecticut:
  • R.T. Jones
  • M. Kornicer
  • B. Evans
  • T. Bogue
• University of Richmond:
  • P. Rubin (now at Dept. Phys. & Astr., George Mason U, Fairfax, VA)
  • E. Collins
  • C. Campbell
  • L. McGlinchey
  • E. Walker
• Renssalaer Polytechnic University:
  • J. Napolitano
  • G.S. Adams
• Catholic University:
  • D.I. Sober
  • H. Crannell
• Jefferson Lab:
  • E. Smith
  • R. Mammei
  • D. Abbott

It was proposed that Richard Jones be listed as primary author on the paper. No opposition was raised.

• Dan now has a set of attenuation corrections and gain constants that allow him to extract an eta signal in 2-gamma effective mass with one photon reconstructed in the barrel and one in the forward calorimeter. The width of this signal is about 120 MeV r.m.s., to be compared with the resolution of 45 MeV for both photons reconstructed in the forward. He also sees a π⁰ signal, although in that case the mass peak is more difficult to distinguish from the background. He has set up new groups in the event structures to hold information from the BGD photons and charged hits, and will work with R.J. to get these certified for check-in to cvs. He is also working on a Tech. Note on his work on reconstruction in the BGD.

• Mihajlo has managed with a set of strict cuts that he calls FULLY_CONTAINED_FORWARD to isolate a signal for the η'(960) meson in 2γ. The background from broken b1 mesons is prohibitive in the higher multiplicity channels like π⁰π⁰ η which in principle should contain many more events because of the larger branching ratio. The large rate of mis-reconstructions in the present code makes the study of multiplicities beyond 3 problematic. He has decided to try to study the clusterizer to see if it can be improved for high-multiplicity events.
• During the first two weeks of this study he has found and solved three long-standing bugs that were present in the analysis, one involving the reconstruction routine makeHits(), one involving the way that hits were being saved by the simulation Gradphi, and one in the LGD clusterizer lgdClusterIU.c code itself. All three have had a major impact on the rate of successful reconstructions. Following these fixes, he has used the event display to identify and isolate 4 classes of cluster patterns that are misrecognized by the clusterizer. He is working on methods to teach the clusterizer how to handle these special cases, which amount to as much as 30% of the sample in higher-multiplicity events. Much more information on this work is found on his project web page at the link listed above.

We plan to continue our online analysis meetings on a bi-weekly basis. The next call is scheduled for Monday, June 28 at 2:00 on VRVS.