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Decoherence Curve and Chemical Composition in CosmoALEPH

This study analyzes the muon lateral distributions in cosmic ray air showers and investigates the composition of these showers using the CosmoALEPH detector. The results shed light on discrepancies between experimental measurements and Monte Carlo predictions. The study also examines the muon spectra and charge ratio, fitting them against different models to determine the primary energy spectrum and composition.

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Decoherence Curve and Chemical Composition in CosmoALEPH

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  1. Decoherence Curve and Chemical Composition in CosmoALEPH Claus Grupen for the CosmoALEPH Collaboration M. Schmelling, N.O. Hashim, C. Grupen, S. Luitz, F. Maciuc, A. Mailov, A.-S. Müller, H.G. Sander, S. Schmeling, R. Tcaciuc, H. Wachsmuth, K. Zuber Heidelberg, Nairobi, Siegen, Bukarest, Baku, Karlsruhe, Mainz, CERN, Dresden

  2. Motivation The muon lateral distributions from Auger and KASCADE-Grande are not in perfect agreement with Monte Carlo predictions. CosmoALEPH only measures the muon component of air showers underground. Possibly CosmoALEPH can throw some light on this problem. Average muon content per energy Juan Carlos Arteaga, KASCADE-Grande Auger (A. Aab et al. Phys. Rev. D 2015)

  3. The ALEPH-experiment

  4. Sensitivity of CosmoALEPH

  5. Decoherence results

  6. preliminary Michael Schmelling 2006

  7. Coincidences per m4 and day VENUS model: H.J. Drescher et al. Nucl. Phys. Proc. Suppl. 75A (1999) 275 Distance between two detectors [m] Some excess at large separations: All used models have this problem. Rodica Tcaciuc 2006

  8. Fit to the CosmoALEPH data (muon spectra and charge ratio) power law assumed for the primary spectra, γ spectral index fh fraction of heavy nulcei assumption for heavy nuclei in the Monte Carlo: 30 % He, 20% N, 30% Mg, 20% Fe (constant mass composition) Models assumed: DPMJET, EPOS, NEXUS, VENUS: fit for fh against γ

  9. M. Schmelling et al. Astropart. Phys. 49 (2013) 1 - 5

  10. Result of the fit: fh < 0.41 and 2.47 < γ < 2.59 A number on the flux of cosmic ray primaries above 100 GeV comes out to be Ф =3.74 0.61 m-2 s -1 sr -1 in good agreement with other measurements + -

  11. Multiplicity Distributions

  12. high multiplicity Event in the ALEPH TPC > 150 tracks

  13. CORSIKA, QGSJET; pμ > 70 GeV V. Avati et al. Astropart. Phys. 19 (2003) 513- 523

  14. Conclusions The decoherence curve – sensitive to the PeV region favours a dominantly light composition The derived primary energy spectrum is in agreement with expectations The high-end of the multiplicity distribution indicates a higher fraction of heavy primaries High-resolution detectors allow precise results in cosmic rays studies

  15. graphic conclusions

  16. muon trident production F. Maciuc et al. Phys. Rev. Lett. 96 (2006) 021801

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