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Jan Ridky and Petr Travnicek Inst. of Physics, Czech Academy of Sciences, Prague for DELPHI collaboration. Muon Bundles from Cosmic Ray Showers Detected by DELPHI at LEP. Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004. Detection of cosmic rays at LEP. ALEPH (140 m, E cut = 70 GeV).
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Jan Ridky and Petr Travnicek Inst. of Physics, Czech Academy of Sciences, Prague for DELPHI collaboration Muon Bundles from Cosmic Ray Showers Detected by DELPHI at LEP Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Detection of cosmic rays at LEP ALEPH (140 m, Ecut = 70 GeV) DELPHI (100 m, Ecut = 50 GeV) L3 (30 m, Ecut = 15 GeV) Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Simulation and detection Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Description of the overburden different kinds of molasses 5 layers with proper rock density & experimental cavern description Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Detektor DELPHI MUB HCAL TOF TPC Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Typical high multiplicity event RUN 107634, EVT 4731 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Saturated event … we have 6 such cases Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Data selection - DELPHI cosmic trigger coincidence of 3 sectors in TOF, parasitic data taking to e+e- and several dedicated cosmic runs Nmuons > 4 Duty cycle of LEP total live time » 1.6 106 s Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Projected angle background rejection HCAL projected angle Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Muon multiplicity 1999, 2000 4 saturated events 2 saturated events (MUB) Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Saturated events • too many hits, reconstruction in HCAL fails • 6 such events, parallel ‘tracks’ of un-hit tubes -> cosmic • 2 events in MUB multiplicity >150 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
MC comparisons Which model provides more muons? LDF of p > 50 GeV muons => QGSJET > SIBYLL > DPMJET Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
HCAL – MC (QGSJET) vs. DATA Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Systematic errors – rock density, cross-talk cross-talk rock density Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Simulations – supposed flux Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
HCAL – MC (QGSJET) vs. DATA flux no. 1 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Comparison – MC vs. DATA flux 1, 2, 3- influence of the flux of primary particles Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Simulations – energy contributions – flux 1 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Simulations – energy contributions – flux 1 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
TPC sky plot (galactic coordinates), HCAL multiplicity > 15 Jan Ridky, ISVHECRI, Pylos, Greece, 6-12 Sept. 2004
Other LEP results Delphi Aleph L3-C multiplicity
Conclusions • DELPHI cosmic data in qualitative agreement with other LEP measurements (L3+C). • High energy models fail to describe muon multiplicity • Data are sensitive to the dynamics of the high energy interactions (talk of Jörg Hörandel) • Cosmic data …. the only measurement at LEP unexplained by theory