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arXiv 2202.11546hep-phastro-ph.HE
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QCD不确定性对暗物质湮灭产生的反质子谱的影响

Impact of QCD uncertainties on antiproton spectra from dark-matter annihilation

Adil Jueid, Jochem Kip, Roberto Ruiz de Austri, Peter Skands

AI总结:

该研究评估QCD不确定性对暗物质湮灭产生反质子谱的影响,发现其可显著改变最佳拟合质量与截面,强调未来暗物质分析需纳入这些不确定性。

摘要:

湮灭或衰变的暗物质粒子在产生对天体物理时间尺度上稳定的粒子之前,会经历一系列复杂的过程,包括强辐射和电磁辐射、强子化以及强子衰变。通过这种方式产生的反质子可能在AMS-02等实验中留下足迹。多个研究小组报告了在10-20 GV的刚性范围内反质子通量存在超出事件。然而,重子产生的理论建模并不直接,部分依赖于蒙特卡洛事件生成器中的唯象模型。在这项工作中,我们评估了QCD不确定性对暗物质湮灭产生的反质子谱的影响。作为原理验证,我们展示了一个仅依赖于热平均湮灭截面(⟨σv⟩)和暗物质质量(Mχ)的双参数模型,QCD不确定性可以影响最佳拟合质量高达约14%(对于大暗物质质量具有较大不确定性),具体取决于Mχ和湮灭通道(b\ar{b}或W+W-)的选择,以及影响⟨σv⟩高达约10%。相比之下,底层扩散参数的变化在1%-5%以内,结果对宇宙线传播模型的选择也相当稳健。这些发现表明,未来的暗物质分析中需要包含QCD不确定性。为了促进全面分析,我们提供了包含QCD不确定性的表格形式谱以及用于质量插值和快速暗物质拟合的代码片段。代码可在GitHub仓库中找到。

英文摘要:

Dark-matter particles that annihilate or decay can undergo complex sequences of processes, including strong and electromagnetic radiation, hadronisation, and hadron decays, before particles that are stable on astrophysical time scales are produced. Antiprotons produced in this way may leave footprints in experiments such as AMS--02. Several groups have reported an excess of events in the antiproton flux in the rigidity range of $10$--$20$ GV. However, the theoretical modeling of baryon production is not straightforward and relies in part on phenomenological models in Monte Carlo event generators. In this work, we assess the impact of QCD uncertainties on the spectra of antiprotons from dark-matter annihilation. As a proof-of-principle, we show that for a two-parameter model that depends only on the thermally-averaged annihilation cross section ($\langle σv \rangle$) and the dark-matter mass ($M_χ$), QCD uncertainties can affect the best-fit mass by up to $\sim 14 \%$ (with large uncertainties for large DM masses), depending on the choice of $M_χ$ and the annihilation channel ($b\bar{b}$ or $W^+ W^-$), and $\langle σv \rangle$ by up to $\sim 10\%$. For comparison, changes to the underlying diffusion parameters are found to be within $1\%$--$5\%$, and the results are also quite resilient to the choice of cosmic-ray propagation model. These findings indicate that QCD uncertainties need to be included in future DM analyses. To facilitate full-fledged analyses, we provide the spectra in tabulated form including QCD uncertainties and code snippets to perform mass interpolations and quick DM fits. The code can be found in this \href{https://github.com/ajueid/qcd-dm.github.io.git}{github} repository.

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