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arXiv 2305.01992astro-ph.HEhep-ph
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利用γ射线数据约束正电子超出的暗物质解释

Constraining the dark matter interpretation of the positron excess with $γ$-ray data

Haoxiang Zhan

AI总结:

该研究结合AMS-02正电子超出数据与银心、矮星系的γ射线观测上限,约束暗物质湮灭参数,发现仅质量约500GeV、湮灭为μ+μ-的暗物质可同时符合两类观测,其他湮灭道贡献有限。

摘要:

暗物质(DM)的粒子起源仍是现代物理学的主要谜题之一。在实验室中探测暗物质最具前景的策略之一,是间接搜寻太空中暗物质湮灭产生的宇宙线粒子。特别是,AMS-02实验已高精度测量了宇宙线正电子的流强,结果表明,相对于次级产生的正电子,10 GeV以上存在超出。本文研究了正电子超出可能的暗物质起源,找出了拟合高能正电子数据所需的暗物质质量$M$和湮灭截面$\u27e8σv\u27e9$的取值。具体而言,我们发现,对于湮灭为$b\ar{b}$的暗物质,需要满足$M=43$ TeV且$\u27e8σv\u27e9 = 10^{-21}$ cm³/s;而对于湮灭为$τ^+τ^-$的情况,则需要$M=2$ TeV且$\u27e8σv\u27e9 = 3×10^{-23}$ cm³/s。如果暗物质能产生正电子,那么它们预计还会从银河系中心以及银河系的矮星系卫星周围产生伽马射线。因此,我们将拟合AMS-02正电子数据得到的暗物质质量和湮灭截面取值,与利用HESS望远镜对银心方向的γ射线未探测结果、以及Fermi-LAT对矮星系的联合分析得到的上限相结合。本文的主要结果是,只有湮灭为$μ^+ μ^-$、质量约为500 GeV且$\u27e8σv\u27e9 = 4×10^{-24}$ cm³/s的暗物质,既能拟合AMS-02数据,又与γ射线观测得到的上限相符。至于$τ^+ τ^-$($b\ar{b}$)湮灭道,暗物质的贡献最多只能达到几十%(百分之几)的水平。

英文摘要:

The particle origin of dark matter (DM) is still one of the main puzzles in modern physics. One of the most promising search strategy to detect DM at laboratories is through the indirect search of cosmic particles that are produced from DM annihilation in space. In particular, the flux of cosmic positrons has been measured with high precision by the AMS-02 experiment demonstrating that an excess above 10 GeV, with respect to the secondary production, is present. We study in this paper the possible DM origin of the positron excess finding the values of the DM mass $M$ and annihilation cross section $\langle σv \rangle$ that are needed to fit high-energy positron data. In particular, we find that for DM annihilating into $b\bar{b}$ it is required to have $M=43$ TeV and $\langle σv \rangle = 10^{-21}$ cm$^3$/s while for $τ^+τ^-$ $M=2$ TeV and $\langle σv \rangle = 3\times 10^{-23}$ cm$^3$/s. If DM produce positrons, they are expected to generate gamma rays from the center of the Milky Way and around dwarf galaxy satellites of the Galaxy. We thus combine the values for the DM mass and annihilation cross section obtained with the fit to AMS-02 positron data with the upper limits derived with the non-detection of $γ$ rays with HESS in the direction of the Galactic center and Fermi-LAT for the combined analysis of dwarf galaxies. The main result of the paper is that only DM annihilating into $μ^+ μ^-$ with a mass around 500 GeV and $\langle σv \rangle = 4\times 10^{-24}$ cm$^3$/s can fit AMS-02 data and be compatible with the upper limits found with $γ$ rays. As for the $τ^+ τ^-$ ($b\bar{b}$) channel, DM can contribute at most at a few tens $\%$ (a few \%) level.

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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