Measurement of the cosmic ray spectrum above 4×1018 eV using inclined events detected with the Pierre Auger Observatory
A. Aab
,
A. Cordier
(1)
,
Balázs Kégl
(1)
,
M. Avenier
(2)
,
C. Berat
(2)
,
S. Le Coz
(2)
,
D. Lebrun
(2)
,
K. Louedec
(2)
,
F. Montanet
(2)
,
A. Stutz
(2)
,
Imen Al Samarai
(3)
,
O. Deligny
(3)
,
I. Lhenry-Yvon
(3)
,
D. Martraire
(3)
,
F. Salamida
(3)
,
T. Suomijärvi
(3)
,
J. Aublin
(4)
,
P. Billoir
(4)
,
L. Caccianiga
(4)
,
Richard Dallier
(5, 6)
,
F. Gate
(6)
,
P.L. Ghia
(4)
,
Pascal Lautridou
(6)
,
A. Letessier-Selvon
(4)
,
J. Maller
(6)
,
V. Marin
(6)
,
Lilian Martin
(6)
,
O. Ravel
(6)
,
Benoît Revenu
(6)
1
LAL -
Laboratoire de l'Accélérateur Linéaire
2 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
3 IPNO - Institut de Physique Nucléaire d'Orsay
4 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
5 USN - Unité Scientifique de la Station de Nançay
6 SUBATECH - Laboratoire SUBATECH Nantes
2 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
3 IPNO - Institut de Physique Nucléaire d'Orsay
4 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
5 USN - Unité Scientifique de la Station de Nançay
6 SUBATECH - Laboratoire SUBATECH Nantes
A. Aab
- Function : Author
C. Berat
- Function : Author
- PersonId : 739578
- IdHAL : corinne-berat
- ORCID : 0000-0001-8294-6294
- IdRef : 033505187
Imen Al Samarai
- Function : Author
- PersonId : 7760
- IdHAL : imen-al-samarai
- IdRef : 164658653
Richard Dallier
- Function : Author
- PersonId : 21330
- IdHAL : richard-dallier
- ORCID : 0000-0001-9452-4849
- IdRef : 120243997
Pascal Lautridou
- Function : Author
- PersonId : 177535
- IdHAL : pascal-lautridou
- ORCID : 0000-0001-8473-6303
- IdRef : 079097405
A. Letessier-Selvon
- Function : Author
- PersonId : 739493
- IdHAL : antoine-letessier-selvon
- ORCID : 0000-0002-2044-3103
- IdRef : 089440757
Lilian Martin
- Function : Author
- PersonId : 1072
- IdHAL : lilian-martin
- ORCID : 0000-0002-9781-2632
- IdRef : 164855645
Benoît Revenu
- Function : Author
- PersonId : 3476
- IdHAL : benoit-revenu
- ORCID : 0000-0002-7629-4805
- IdRef : 068687893
Abstract
A measurement of the cosmic-ray spectrum for energies exceeding 4×1018 eV is presented, which is based on the analysis of showers with zenith angles greater than 60∘ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×1018 eV, the "ankle", the flux can be described by a power law E−γ with index γ=2.70±0.02(stat)±0.1(sys) followed by a smooth suppression region. For the energy (Es) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)+1.0−1.2(sys))×1019 eV.