Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with the Pierre Auger Observatory

We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop.

Note:

Published version, 11 pages, 3 figures, 1 table, Supplemental material appended

Elementary Particles and Fields
showers: atmosphere
fluctuation: measured
interaction: model
model: hadronic
cosmic radiation: UHE
Cherenkov counter: water
particle: model
muon
electromagnetic component

References(59)

Figures(11)

[1]

The Pierre Auger Cosmic Ray Observatory

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- Nucl.Instrum.Meth.A 798 (2015) 172-213
•
e-Print:
- 1502.01323
•
DOI:
- 10.1016/j.nima.2015.06.058

[2]

Structure of large showers at depth 834 g=cm2, applications, in Proceedings of the 15th Int. Cosmic Ray Conf., Plovdiv, Bulgaria (Bulgarian Academy of Sciences, Bulgaria,), Vol. 12, p. 89

J. Linsley

[3]

Reconstruction of Inclined Air Showers Detected with the Pierre Auger Observatory

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- JCAP 08 (2014) 019
•
e-Print:
- 1407.3214
•
DOI:
- 10.1088/1475-7516/2014/08/019

[4]

Characterisation of the electromagnetic component in ultra-high energy inclined air showers

- Astropart.Phys. 32 (2010) 304-317
•
e-Print:
- 0910.2873
•
DOI:
- 10.1016/j.astropartphys.2009.09.008

[5]

Muons in Air Showers at the Pierre Auger Observatory: Mean Number in Highly Inclined Events

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- Phys.Rev.D 91 (2015) 3, 032003,
- Phys.Rev.D 91 (2015) 5, 059901 (erratum)
•
e-Print:
- 1408.1421
•
DOI:
- 10.1103/PhysRevD.91.032003

[5]

Muons in Air Showers at the Pierre Auger Observatory: Mean Number in Highly Inclined Events

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- Phys.Rev.D 91 (2015) 3, 032003,
- Phys.Rev.D 91 (2015) 5, 059901 (erratum)
•
e-Print:
- 1408.1421
•
DOI:
- 10.1103/PhysRevD.91.032003

[6]

Air showers, hadronic models, and muon production

S.J. Sciutto
(
- La Plata, Inst. Natl. Phys. and
- Buenos Aires, CONICET
)

- EPJ Web Conf. 210 (2019) 02007
•
e-Print:
- 1904.12056
•
DOI:
- 10.1051/epjconf/201921002007

[7]

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- Phys.Rev.Lett. 117 (2016) 19, 192001
•
e-Print:
- 1610.08509
•
DOI:
- 10.1103/PhysRevLett.117.192001

[8]

Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory: Measurements at Energies above $10^{17.8}$ eV

Pierre Auger

Collaboration

•

Alexander Aab
(
- Siegen U.
)

et al.

- Phys.Rev.D 90 (2014) 12, 122005
•
e-Print:
- 1409.4809
•
DOI:
- 10.1103/PhysRevD.90.122005

[9]

Measurement of the average shape of longitudinal profiles of cosmic-ray air showers at the Pierre Auger Observatory

Pierre Auger

Collaboration

•

Alexander Aab
(
- Nijmegen U., IMAPP
)

et al.

- JCAP 03 (2019) 018
•
e-Print:
- 1811.04660
•
DOI:
- 10.1088/1475-7516/2019/03/018

[10]

Direct measurement of the muonic content of extensive air showers between $\mathbf { 2\times 10^{17}}$ and $\mathbf {2\times 10^{18}}~$ eV at the Pierre Auger Observatory

Pierre Auger

Collaboration

•

A. Aab
(
- Nijmegen U., IMAPP
)

et al.

- Eur.Phys.J.C 80 (2020) 8, 751
•
DOI:
- 10.1140/epjc/s10052-020-8055-y

[11]

(EAS-MSU1, IceCube, KASCADE-Grande, NEVOD-DECOR, Pierre Auger, SUGAR, Telescope Array, and Yakutsk EASArray Collaborations), Working group report on the combined analysis of muon density measurements from eight air shower experiments, Proc. Sci., ICRC214