Title: The new interaction suggested by the anomalous $^8$Be transition sets a rigorous constraint on the mass range of dark matter Show Chinese title

Title: 由异常的$^8$铍跃迁提出的新的相互作用对暗物质的质量范围设定了严格的约束

Abstract: The WIMPs are considered one of the favorable dark matter (DM) candidates, but as the upper bounds on the interactions between DM and standard model (SM) particles obtained by the upgraded facilities of DM direct detections get lower and lower. Researchers turn their attentions to search for less massive DM candidates, i.e. light dark matter of MeV scale. The recently measured anomalous transition in $^8$Be suggests that there exists a vectorial boson which may mediate the interaction between DM and SM particles. Based on this scenario, we combine the relevant cosmological data to constrain the mass range of DM, and have found that there exists a model parameter space where the requirements are satisfied, a range of $10.4 \lesssim m_{\phi} \lesssim $ 16.7 MeV for scalar DM, and $13.6 \lesssim m_{V} \lesssim $ 16.7 MeV for vectorial DM is demanded. Then a possibility of directly detecting such light DM particles via the DM-electron scattering is briefly studied in this framework. Show Chinese abstract

Abstract: WIMPs被认为是暗物质（DM）的有利候选者之一，但随着暗物质直接探测设施的升级，对暗物质与标准模型（SM）粒子之间相互作用的上限不断降低。研究人员开始关注寻找质量更小的暗物质候选者，即MeV量级的轻暗物质。最近测量的$^8$铍中的异常跃迁表明，存在一种矢量玻色子，可能介导暗物质与标准模型粒子之间的相互作用。基于此情景，我们结合相关的宇宙学数据来限制暗物质的质量范围，并发现存在一个模型参数空间满足要求，标量暗物质需要$10.4 \lesssim m_{\phi} \lesssim $16.7 MeV的范围，矢量暗物质需要$13.6 \lesssim m_{V} \lesssim $16.7 MeV的范围。然后在该框架下简要研究了通过暗物质-电子散射直接探测这种轻暗物质的可能性。