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arXiv 1701.06149astro-ph.HEhep-ph
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宇宙射线在AMS-02时代的传播

Propagation of cosmic rays in the AMS-02 era

Qiang Yuan, Su-Jie Lin, Kun Fang, Xiao-Jun Bi

摘要:

在这项工作中,我们使用AMS-02新报道的硼碳比(B/C)和PAMELA和AMS-02的随时间变化的质子通量来约束银河系中宇宙射线的源和传播参数。太阳调制参数与太阳活动的线性相关性被假定为占随时间变化的宇宙线通量。一套全面的传播模型,有/无再加速或对流,进行了讨论和比较。我们发现,只有再加速模型可以自洽地拟合质子和B/C数据。扩散系数$δ$的刚性依赖斜率对于扩散-再加速模型而言约为$0.38-0.50$。平原扩散和扩散对流模型拟合数据较差。我们比较不同的模型预测的正电子和反质子通量的数据。我们发现,扩散再加速模型过度产生低能量的正电子,而非再加速模型提供更好的拟合的数据。至于反质子,再加速模型倾向于低估低能量反质子通量,除非扩散系数的速度依赖性的唯象修正。我们的研究结果表明,无论是在银河系还是在太阳日球层中,原子核和轻子的传播都可能存在重要的差异。

英文摘要:

In this work we use the newly reported Boron-to-Carbon ratio (B/C) from AMS-02 and the time-dependent proton fluxes from PAMELA and AMS-02 to constrain the source and propagation parameters of cosmic rays in the Milky Way. A linear correlation of the solar modulation parameter with solar activities is assumed to account for the time-varying cosmic ray fluxes. A comprehensive set of propagation models, with/without reacceleration or convection, have been discussed and compared. We find that only the models with reacceleration can self-consistently fit both the proton and B/C data. The rigidity dependence slope of the diffusion coefficient, $δ$, is found to be about $0.38-0.50$ for the diffusion-reacceleration models. The plain diffusion and diffusion-convection models fit the data poorly. We compare different model predictions of the positron and antiproton fluxes with the data. We find that the diffusion-reacceleration models over-produce low energy positrons, while non-reacceleration models give better fit to the data. As for antiprotons, reacceleration models tend to under-predict low energy antiproton fluxes, unless a phenomenological modification of the velocity-dependence of the diffusion coefficient is applied. Our results suggest that there could be important differences of the propagation for nuclei and leptons, in either the Milky Way or the solar heliosphere.

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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