CosmoLep 3 (1998)

Minutes of the CosmoLep Meeting, 8 July 1998

I. Ajinenko (Delphi), V. Avati (CosmoLep), P. Baillon (Delphi), M. Battaglia (Delphi), G. Beetham, B. Betev(L3), G. Bianchetti, S. Czellar (Delphi), K. Eggert (CosmoLep), F. Franco (CosmoLep), A. Fucci, M. Kaijansinkko (CosmoLep), R. Leiste (L3), R. Orava (Delphi), K. Osterberg (Delphi), J. Schieck (Opal), S. Schmitt (Opal), J. Strom (CosmoLep), G. Valenti (Delphi), J. Valiviita (Delphi), H. Wachsmuth (Aleph), Z. Yu (L3), T. Ziegler (Aleph).

• The first part of the meeting was devoted to the general time measurement needed to put the different experiments in coincidence. Gary Beetham reported on his experience with the GPS system distributed over the LEP ring. This system, commercially available, will be further tested and the results will be transmitted to the electronic pool. We hope that with the help of the experts a standardized GPS system will be soon available from the pool. Antennas exist already for all the experiments (see report of Gary Beetham). It was mentioned that existing optical links between the experiments could also be used. Adolfo Fucci drew the attention to the laser-based TTC system developed by Bruce Taylor.
• Rudolf Leiste (L3) commented the experience of the L3-C group with their GPS system.
• Gianni Valenti (Delphi) presented the trigger possibilities on muons and rates of individual sectors (LEP off).

  

  The rates should be re-measured in a non pointing geometry. The duty cycle for muon data taking would be 2.8 sec/22.2 sec during LEP data taking and 2.8 sec/11.44 sec otherwise. A trigger on multimuon bundles (n 4) should be studied and could be complemented with an inclusive muon trigger, running part-time. Studies continue on the possibility of a parallel read-out of some calorimeter sections.

• Marco Battaglia (Delphi) presented results of the cosmic runs in spring 1998 during beam-off time. 100K events have been taken during 10 days run. The time distribution of the muon events shows that most of the data were taken in a time windows of 600 nsec with a tail reaching 1 sec. Preliminary muon multiplicity distributions with a momentum cut of 3 and 10 GeV/c were presented. Would large multiplicity events be eliminated by software cuts in the higher level triggers or in the reconstruction? The momentum distribution of the muons extend to 100 GeV.
• Delphi took cosmic in the period 20-24.4.98 corresponding to about 66 hours. These events have been scanned and the results have been presented by Jussi Valiviita. The shape of the multimuon distribution agrees with the one shown by M. Battaglia.

  In summary:
  

  

• A few outstanding multimuon events with about 100 muons, taken in 1997 by Aleph were presented by Thomas Ziegler.
• Jochen Schieck (Opal): the collaboration is interested in CosmoLep; a group from University of Alberta is willing to work for CosmoLep
• CosmoLep will be on WWW (http://www.cern.ch/CosmoLep) with links to the individual Lep-experiments.

NEXT MEETING: 5 AUGUST , 16.00 room 1-1-25

Preliminary Agenda

• Multimuon events from
  • Aleph
  • Delphi
• Muon momentum cut-off versus angle for the different experiments
• Some simulations results
• Discussion on:
  • analysis strategy
  • trigger strategy
  • simulation
• Workshop on multimuon bundles