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CosmoLep 1 (1998)

Minutes of the CosmoLep Meeting, 20 May 1998

Proposed Agenda:

• News about CosmoLep and CosmoAleph
• Discussion of ideas how to continue (proposal to LEPC, infrastructure, communication....)
• What is needed/available/feasible in the four LEP experiments (GBX-independent trigger, event time stamps, read-out, sensitive time etc....)

: Introduction of CosmoLep (Started 4 years ago by Horst) and status of CosmoAleph.

CosmoLep has now become an initiative of EP division.

: CosmoLep

• Goal: measurement of muon spectrum, multimuon bundles; observation of large distance coincidences
  • measure and momentum analyze cosmic ray muons at 50-100 m underground where electromagnetic and hadronic components are fully absorbed. The number of multi-muons events is large. Aleph has a beautiful event with >50 muons in the central tracker
  • extend the measurement over the four LEP detectors with distances over few kilometers
  • the four experiments have detectors with different systematics and muon energy cuts
  • search for coincidences between the LEP experiments. If positive evidences would be found, extend the array over Europe.

• How to start:
  • create a CosmoLep group including members of the 4 LEP experiments
  • analyze existing cosmic rays data
  • discuss a common strategy for the four experiments
  • find arguments from cosmic ray community in favor of CosmoLep
  • prepare a proposal to be submitted to the LEPC

• Questions to the LEP experiments:
  • Is your collaboration interested to participate with a subgroup to CosmoLep? If possible give names of interested people and their field of activity in your experiment.
  • Which detectors are needed to trigger on cosmic rays and momentum analyze the muons (precision, p-cut, acceptance....)?
  • Would an individual cosmic muon trigger be possible in special runs outside LEP runs and during LEP runs?
  • Can a common timing signal be installed (GPS)?
  • Is the analysis of the existing cosmic muon data possible?

P. LE COULTRE (L3)

Answers to the questions : the L3 muon trigger is independent of the standard L3 trigger,the muon momentum can be precisely determined via the muon chambers. Individual muon trigger is possible during a LEP run. Outside the LEP run it is very expensive to keep the detectors on. The GPS is already running. The analysis of the old data would be possible but it's a hard job. Presently the analysis of 1991 data (used for the calibration) is proceeding.

H. WACHSMUTH (ALEPH)

Answers to the questions: the trigger is independent, the momentum analysis not because we are not reading the muon chambers, the individual muon trigger is possible during a LEP run. The GPS is installed.

D. PLANE (OPAL)

Discussion at the next OPAL meeting in two weeks

R. ORAVA (DELPHI)

Delphi is interested: presently we are looking at the trigger in the hadronic calorimeter. There are the old data from the calibration runs that can be analysed.

The next meeting was foreseen on June 3, but to have some time for discussions we propose to shift the meeting by one week.
NEXT MEETING: 10 JUNE , 15.00 room 1-1-25

Proposed agenda (suggestions are welcome):

• answers about CosmoLep participation by the four LEP experiments
• discussion on details about common triggering and data analysis