arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2002.11406astro-ph.HEhep-ph
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AMS-02(Li,Be,B)/C、N/O、3 He和4 He数据的联合分析

Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data

Nathanael Weinrich, Yoann Génolini, Mathieu Boudaud, Laurent Derome, David Maurin

摘要:

AMS-02实验测量了几个次级与初级的比率,从而能够详细研究银河系宇宙射线的传输。我们约束以前推导的基准情景(仅基于AMS-02 B/C数据),使用其他二级到初级比率,以测试运输的普遍性和存在的低刚性扩散中断。我们使用的一维薄盘/厚晕传播模型USINE和$χ^2$最小化占误差的协方差矩阵(AMS-02系统)和滋扰参数(横截面和太阳调制的不确定性)。AMS-02 Li/C、Be/C和B/C的组合分析加强了$δ=0.50\pm 0.03$的扩散斜率的情况,其中扩散系数在GV刚度下具有低刚度的突变或上升。我们的简单模型可以成功地再现所有考虑的数据(Li/C、Be/C、B/C、N/O和3 He/4 He),但仍存在几个问题:(i)定量一致性取决于AMS-02数据系统中相关长度约束不好的假设;(ii)组合分析对生产截面非常敏感,并且我们发现拟合后的值与其最可能的值相差$\sim5-15\%$(大致在目前估计的核不确定性范围内);(iii)参数空间的两个非常不同的区域仍然是可行的,要么有再加速和对流,要么有纯粹的扩散输运。为了充分利用AMS-02数据的综合分析,需要更好的核数据和更好地处理数据系统中的能量相关性。人们热切期待AMS-02关于较重物质的数据,以进一步探索宇宙射线传播的情景。

英文摘要:

The AMS-02 experiment measured several secondary-to-primary ratios enabling a detailed study of Galactic cosmic-ray transport. We constrain previously derived benchmark scenarios (based on AMS-02 B/C data only) using other secondary-to-primary ratios, to test the universality of transport and the presence of a low-rigidity diffusion break. We use the 1D thin disc/thick halo propagation model of USINE and a $χ^2$ minimisation accounting for a covariance matrix of errors (AMS-02 systematics) and nuisance parameters (cross-sections and solar modulation uncertainties). The combined analysis of AMS-02 Li/C, Be/C, and B/C strengthens the case for a diffusion slope of $δ=0.50\pm 0.03$ with a low-rigidity break or upturn of the diffusion coefficient at GV rigidities. Our simple model can successfully reproduce all considered data (Li/C, Be/C, B/C, N/O, and 3He/4He), although several issues remain: (i) the quantitative agreement depends on the assumptions made on the not well constrained correlation lengths of AMS-02 data systematics; (ii) combined analyses are very sensitive to production cross sections, and we find post-fit values differing by $\sim5-15\%$ from their most likely values (roughly within currently estimated nuclear uncertainties); (iii) two very distinct regions of the parameter space remain viable, either with reacceleration and convection, or with purely diffusive transport. To take full benefit of combined analyses of AMS-02 data, better nuclear data and a better handle on energy correlations in the data systematic are required. AMS-02 data on heavier species are eagerly awaited to further explore cosmic-ray propagation scenarios.

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