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Second dip as a signature of ultrahigh energy proton interactions with cosmic microwave background radiation

V. Berezinsky·A. Gazizov·M. Kachelrieß
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Abstract

We discuss as a new signature for the interaction of extragalactic ultrahigh energy protons with cosmic microwave background radiation a spectral feature located at $E=6.3\times 10^{19}$ eV in the form of a narrow and shallow dip. It is produced by the interference of $e^+e^-$-pair and pion production. We show that this dip and in particular its position are almost model-independent. Its observation by future ultrahigh energy cosmic ray detectors may give the conclusive confirmation that an observed steepening of the spectrum is caused by the Greisen-Zatsepin-Kuzmin effect.

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V. Berezinsky, A. Gazizov, M. Kachelrieß. 2006-12-10. Second dip as a signature of ultrahigh energy proton interactions with cosmic microwave background radiation. https://doi.org/10.1103/physrevlett.92.231101

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