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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2407.18318 |
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| _version_ | 1866929754752417792 |
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| author | Pawlowsky, Jannis Kampert, Karl-Heinz Rautenberg, Julian |
| author_facet | Pawlowsky, Jannis Kampert, Karl-Heinz Rautenberg, Julian |
| contents | We examine the probability of proton-induced air showers at $E>10\,$EeV being misidentified as photon-induced due to neutral pions receiving a major part of the primary energy in the first interaction, thereby enhancing the electromagnetic shower component by their $π^0 \to γγ$ decay. Using CORSIKA simulations, we demonstrate the relevance of this effect at EeV energies. However, the probability for such photon-like events drops down strongly at the highest energies due to the increasing probability of Lorentz boosted $π^0$'s suffering hadronic interactions before decay. Different hadronic interaction models suggest that photon-like hadronic events may be observed at current UHECR observatories. A quantitative comparison of the observed number of background events found in recent photon searches published by the Pierre Auger Collaboration allows us conclude that the hypothesis of upwards fluctuations of $π^0$-production alone is insufficient to explain the data. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_18318 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Photon-likeness of hadron showers and impact of Lorentz boosting Pawlowsky, Jannis Kampert, Karl-Heinz Rautenberg, Julian High Energy Physics - Phenomenology High Energy Astrophysical Phenomena We examine the probability of proton-induced air showers at $E>10\,$EeV being misidentified as photon-induced due to neutral pions receiving a major part of the primary energy in the first interaction, thereby enhancing the electromagnetic shower component by their $π^0 \to γγ$ decay. Using CORSIKA simulations, we demonstrate the relevance of this effect at EeV energies. However, the probability for such photon-like events drops down strongly at the highest energies due to the increasing probability of Lorentz boosted $π^0$'s suffering hadronic interactions before decay. Different hadronic interaction models suggest that photon-like hadronic events may be observed at current UHECR observatories. A quantitative comparison of the observed number of background events found in recent photon searches published by the Pierre Auger Collaboration allows us conclude that the hypothesis of upwards fluctuations of $π^0$-production alone is insufficient to explain the data. |
| title | Photon-likeness of hadron showers and impact of Lorentz boosting |
| topic | High Energy Physics - Phenomenology High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2407.18318 |