Title

All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Authors

R. Alfaro, Universidad Nacional Autónoma de México
C. Alvarez, Universidad Autónoma de Chiapas
J. D. Álvarez, Universidad Michoacana de San Nicolás de Hidalgo
R. Arceo, Universidad Autónoma de Chiapas
J. C. Arteaga-Velázquez, Universidad Michoacana de San Nicolás de Hidalgo
D. Avila Rojas, Universidad Nacional Autónoma de México
H. A. Ayala Solares, Michigan Technological University
A. S. Barber, The University of Utah
A. Becerril, Universidad Nacional Autónoma de México
E. Belmont-Moreno, Universidad Nacional Autónoma de México
S. Y. Benzvi, University of Rochester
C. Brisbois, Michigan Technological University
K. S. Caballero-Mora, Universidad Autónoma de Chiapas
T. Capistrán, Instituto Nacional de Astrofisica Optica y Electronica
A. Carramiñana, Instituto Nacional de Astrofisica Optica y Electronica
S. Casanova, Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences
M. Castillo, Universidad Michoacana de San Nicolás de Hidalgo
U. Cotti, Universidad Michoacana de San Nicolás de Hidalgo
J. Cotzomi, Benemerita Universidad Autonoma de Puebla
S. Coutiño De León, Instituto Nacional de Astrofisica Optica y Electronica
C. De León, Benemerita Universidad Autonoma de Puebla
E. De La Fuente, Universidad de Guadalajara
R. Diaz Hernandez, Instituto Nacional de Astrofisica Optica y Electronica
S. Dichiara, Universidad Nacional Autónoma de México
B. L. Dingus, Los Alamos National Laboratory
M. A. Duvernois, University of Wisconsin-Madison
J. C. Díaz-Vélez, Universidad de Guadalajara
R. W. Ellsworth, George Mason University, Fairfax Campus
O. Enriquez-Rivera, Universidad Nacional Autónoma de México
D. W. Fiorino, University of Maryland
H. Fleischhack, Michigan Technological University
N. Fraija, Universidad Nacional Autónoma de México

Document Type

Article

Publication Date

12-15-2017

Abstract

© 2017 American Physical Society. We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground-based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken over 234 days between June 2016 and February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of -2.49±0.01 prior to a break at (45.7±0.1) TeV, followed by an index of -2.71±0.01. The spectrum also represents a single measurement that spans the energy range between direct detection and ground-based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.

Publication Title

Physical Review D

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