More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles (FCPs) still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the Dark Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times {10}^{-10}{\mathrm{cm}}^{-2}{\mathrm{sr}}^{-1}{\mathrm{s}}^{-1}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays.

中文翻译：

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寻找空间中的相对论分数带电粒子

在油滴实验进行一个多世纪后，部分带电粒子（FCP）的可能存在仍未解决。寻找 FCP 对于粒子物理学中标准模型的某些扩展至关重要。大多数先前在宇宙射线中进行的 FCP 搜索都是基于地下或高海拔的实验。然而，除了航天飞机飞行的 AMS-01 和大气层顶部的气球飞行的 BESS 之外，在轨道上进行的宇宙射线中的 FCP 搜索很少。在这项研究中，我们根据使用暗物质粒子探测器 (DAMPE) 卫星在五年内获得的在轨数据在太空中进行 FCP 搜索。与需要数百 GeV 量级的 FCP 能量的地下实验不同，我们的 FCP 搜索仅从几个 GeV 开始。$6.2\times {10}^{-10}{\mathrm{厘米}}^{-2}{\mathrm{sr}}^{-1}{\mathrm{s}}^{-1}$获得通量。我们的结果表明，DAMPE 比类似类型的实验表现出更高的灵敏度三个数量级，这更严格地限制了初级宇宙射线中 FCP 的存在条件。