Published February 6, 2015
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Muons in air showers at the Pierre Auger Observatory: Mean number in highly inclined events

Creators

  • 1. Max Planck Society
  • 2. National Technological University
  • 3. National Autonomous University of Mexico
  • 4. University of Santiago de Compostela
  • 5. University of Hamburg
  • 6. University of Naples Federico II
  • 7. Radboud University Nijmegen
  • 8. City University of New York
  • 9. University of Wisconsin–Milwaukee
  • 10. University of Lisbon
  • 11. Complutense University of Madrid
  • 12. University of Grenoble
  • 13. Politehnica University of Bucharest
  • 14. University of Adelaide
  • 15. Karlsruhe Institute of Technology
  • 16. Ohio State University
  • 17. University of Wuppertal
  • 18. University of Turin
  • 19. Academy of Sciences of the Czech Republic
  • 20. Federal University of Rio de Janeiro
  • 21. Polish Academy of Sciences
  • 22. Colorado State University
  • 23. University of Siegen
  • 24. University of Granada
  • 25. CINVESTAV
  • 26. University of Milan
  • 27. University of Rome Tor Vergata
  • 28. University of Catania
  • 29. University of Salento
  • 30. Universidad Michoacana de San Nicolás de Hidalgo
  • 31. State University of Campinas
  • 32. Pennsylvania State University
  • 33. Case Western Reserve University
  • 34. University of Chicago
  • 35. Centre national de la recherche scientifique
  • 36. University of Nantes
  • 37. University of Buenos Aires
  • 38. Federal Fluminense University
  • 39. University of São Paulo
  • 40. University of Alcalá
  • 41. Michigan Technological University
  • 42. University of L'Aquila
  • 43. University of Groningen
  • 44. National University of La Plata
  • 45. RWTH Aachen University
  • 46. Fermilab
  • 47. ASTRON
  • 48. New York University
  • 49. University of Nova Gorica
  • 50. State University of Feira de Santana
  • 51. University of New Mexico
  • 52. Universidade Federal do ABC
  • 53. Benemérita Universidad Autónoma de Puebla
  • 54. University of Leeds
  • 55. Louisiana State University
  • 56. Colorado School of Mines
  • 57. Universidade Federal de Pelotas
  • 58. Charles University in Prague
  • 59. Northeastern University
  • 60. Federal University of Bahia
  • 61. University of Nebraska–Lincoln
  • 62. INAF
  • 63. University of Bucharest
  • 64. Los Alamos National Laboratory

Description

We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62° and 80°. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 1019eV shower with a zenith angle of 67°, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68±0.04±0.48(sys))×107 muons with energies larger than 0.3 GeV. The logarithmic gain dlnNμ/dlnE of muons with increasing energy between 4×1018eV and 5×1019eV is measured to be (1.029±0.024±0.030(sys)).
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