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arXiv 0904.2372astro-ph.IM
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大倾角空气簇射地面上μ子密度分布的唯象模型

A phenomenological model of the muon density profile on the ground of very inclined air showers

Hans Dembinski, Pierre Billoir, Olivier Deligny, Thomas Hebbeker

摘要:

超高能宇宙射线在地球大气层中产生广泛的空气簇射。重建超高能宇宙射线能量的标准方法是用地面探测器阵列对空气簇射地面上粒子密度的横向分布进行采样。对于具有大倾角的宇宙射线,这种重建是基于在地面上观察到的μ子密度的横向轮廓的模型,该模型适合于在单个表面探测器中观察到的μ子密度。这项任务的最佳模型来自详细的蒙特卡罗模拟的空气淋浴的发展。我们提出了一个唯象的参数化方案,它允许直接从一组单独的蒙特卡罗模拟空气簇射拟合的μ子密度的平均横向分布的模型。该模型以高精度再现了详细的模拟。作为一个例子,我们生成了一个μ子密度模型,该模型在能量范围1e18 eV < E < 1e20 eV和天顶距范围60度<θ < 90度内是有效的。我们将进一步展示一种方法,以加快模拟这样的μ子配置文件的三个数量级,如果只有在淋浴的μ子感兴趣。

英文摘要:

Ultra-high energy cosmic rays generate extensive air showers in Earth's atmosphere. A standard approach to reconstruct the energy of an ultra-high energy cosmic rays is to sample the lateral profile of the particle density on the ground of the air shower with an array of surface detectors. For cosmic rays with large inclinations, this reconstruction is based on a model of the lateral profile of the muon density observed on the ground, which is fitted to the observed muon densities in individual surface detectors. The best models for this task are derived from detailed Monte-Carlo simulations of the air shower development. We present a phenomenological parametrization scheme which allows to derive a model of the average lateral profile of the muon density directly from a fit to a set of individual Monte-Carlo simulated air showers. The model reproduces the detailed simulations with a high precision. As an example, we generate a muon density model which is valid in the energy range 1e18 eV < E < 1e20 eV and the zenith angle range 60 deg < theta < 90 deg. We will further demonstrate a way to speed up the simulation of such muon profiles by three orders of magnitude, if only the muons in the shower are of interest.

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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