Articulo
An upper limit to the photon fraction in cosmic rays above 10<sup>19</sup> eV from the Pierre Auger Observatory
Autor
Badagnani, Daniel Omar
Dova, María Teresa
Epele, Luis Nicolás
Gómez Albarracín, Flavia Alejandra
Grunfeld, Christian Martín
Manceñido, Mónica E.
Sciutto, Sergio Juan
Tueros, Matías Jorge
Veiga, Alejandro Luis
Wahlberg, Hernán Pablo
The Pierre Auger Collaboration
Institución
Resumen
An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 10<sup>19</sup> eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample support the conclusion that a photon origin of the observed events is not favored. Facultad de Ciencias Exactas