The Telescope Array experiment has recently reported the most energetic event detected in the hybrid technique era, with a reconstructed energy of 240 EeV, which has been named “Amaterasu” after the Shinto deity. Its origin is intriguing since no powerful enough candidate sources are located within the region consistent with its propagation horizon and arrival direction. In this work, we investigate the possibility of describing its origin in a scenario of new physics, specifically under a Lorentz Invariance Violation (LIV) assumption. The kinematics of UHECR propagation under a phenomenological LIV approach is investigated. The total mean free path for a particle with Amaterasu's energy increases from a few Mpc to hundreds of Mpc for -δhad,0 > 10-22, expanding significantly the region from which it could have originated. A combined fit of the spectrum and composition data of Telescope Array under different LIV assumptions was also performed. The data is best fitted with some level of LIV both with and without Amaterasu. Robustness with data from the Pierre Auger Observatory is investigated by exploring an intermediate composition scenario. Similar improvements in the description of the data with LIV are found for that. New physics in the form of LIV could, thus, provide a plausible and robust explanation for the Amaterasu particle.

中文翻译：

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新物理学作为天照大神粒子的可能解释


望远镜阵列实验最近报告了在混合技术时代检测到的最有能量的事件，重建的能量为 240 EeV，以神道教神灵的名字命名为“天照大神”。它的起源很有趣，因为在该区域内没有足够强大的候选源，这与它的传播范围和到达方向一致。在这项工作中，我们研究了在新物理学场景中描述其起源的可能性，特别是在洛伦兹不变性违规 （LIV） 假设下。研究了现象学 LIV 方法下 UHECR 传播的运动学。对于-δhad，0 > 10-22，具有天照大神能量的粒子的总平均自由程从几 Mpc 增加到数百 Mpc，显著扩大了它可能起源的区域。还对不同 LIV 假设下的 Telescope Array 的光谱和成分数据进行了组合拟合。该数据最适合有和没有天照大神的一定程度的 LIV。通过探索中间成分情景来研究来自 Pierre Auger 天文台的数据的稳健性。为此，在 LIV 的数据描述中发现了类似的改进。因此，LIV 形式的新物理学可以为天照大神粒子提供一个合理而有力的解释。