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arXiv 2012.06861astro-ph.HE
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超高能宇宙射线的谱线组成和质子-空气截面的测量

The spectra and composition of Ultra High Energy Cosmic Rays and the measurement of the proton-air cross section

Paolo Lipari

摘要:

极高能量宇宙线粒子在大气中产生的簇射的纵向发展的形状编码了关于通量的质量组成的信息,以及控制簇射发展的强子相互作用的性质。对皮埃尔·俄歇天文台测量的具有$E \gtrsim 10^{17.3}$ eV的簇射的最大分布深度的平均值和宽度的能量依赖性的研究表明,在与现有模型进行比较的基础上,宇宙射线通量的组成经历了一个非常重要的演变,首先变得更轻,然后迅速变重。这些结论如果得到证实,将对我们理解高能天体物理源产生深远而令人惊讶的影响。俄歇和望远镜阵列协作组利用对同一能量范围内最大分布深度形状的研究来测量质子在空气中的相互作用长度,这个量可以用来估计$\sqrt{s}$值远高于大型强子对撞机范围时的$pp$截面。在本文中,我们认为,它是可取的结合宇宙线的组成与那些旨在测量的$p$ -空气截面的研究。后者允许获得的通量,可以是解码的组成和它的能量依赖性的很大帮助的质子的分数的估计。考虑多个参数来表征最大分布深度的研究也提供了对用于描述高能簇射的模型的有效性进行更敏感测试的可能性。

英文摘要:

The shape of the longitudinal development of the showers generated in the atmosphere by very high energy cosmic ray particles encodes information about the mass composition of the flux, and about the properties of hadronic interactions that control the shower development. Studies of the energy dependence of the average and width of the depth of maximum distribution of showers with $E \gtrsim 10^{17.3}$ eV measured by the Pierre Auger Observatory, suggest, on the basis of a comparison with current models, that the composition of the cosmic ray flux undergoes a very important evolution, first becoming lighter and then rapidly heavier. These conclusions, if confirmed, would have profound and very surprising implications for our understanding of the high energy astrophysical sources. Studies of the shape of the depth of maximum distribution in the same energy range have been used by Auger and by the Telescope Array Collaboration to measure the interaction length of protons in air, a quantity that allows to estimate the $pp$ cross sections for values of $\sqrt{s}$ well above the LHC range. In this paper we argue that it is desirable to combine the studies of the cosmic ray composition with those aimed at the measurement of the $p$--air cross section. The latter allow to obtain estimates for the fraction of protons in the flux that can be of great help in decoding the composition and its energy dependence. Studies that consider multiple parameters to characterize the depth of maximum distributions also offer the possibility to perform more sensitive tests of the validity of the models used to describe high energy showers.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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