我们在假设轻中微子为狄拉克型的前提下，研究了未来轻子对撞机对轻子暗物质（DM）的探测前景。我们采用有效场论（EFT）方法，写出了连接标准模型（SM）场、轻狄拉克中微子与暗物质的六维算符。考虑暗物质遗迹通过热退耦机制产生，我们通过单光子加丢失能量搜索渠道，检验了未来轻子对撞机的探测前景。轻狄拉克中微子的右手征分量会因与热浴及轻子暗物质的相互作用而热化，导致有效相对论自由度$N_{\ m eff}$升高，处于未来宇宙微波背景（CMB）实验的可探测范围内。结合来自暗物质遗迹与$N_{\ m eff}$的宇宙学观测、暗物质直接与间接探测、天体物理及对撞机观测的现有约束，未来电子对撞机与缪子对撞机具备可观的探测前景，同时未来CMB实验可提供互补性信号。
英文摘要：
We study the discovery prospects of leptophilic dark matter (DM) in future lepton colliders by considering the light neutrinos to be of Dirac type. Adopting an effective field theory (EFT) approach, we write down dimension six operators connecting the standard model (SM) fields, light Dirac neutrinos and DM. Considering DM relic to be generated via the thermal freeze-out, we check the discovery prospects at future lepton colliders via mono-photon plus missing energy searches. The right chiral parts of light Dirac neutrinos get thermalised due to their interactions with the bath as well as leptophilic DM, leading to enhanced effective relativistic degrees of freedom $N_{\rm eff}$ within reach of future cosmic microwave background (CMB) experiments. The interplay of existing bounds from cosmological observations related to DM relic and $N_{\rm eff}$, direct and indirect detection of DM, astrophysics and collider observations leave promising discovery prospects at future electron and muon colliders along with complementary signatures at future CMB experiments.
Constraints on a Light Leptophilic Scalar from Dark-Sector Couplings
Physics Department and INFN Sezione di Roma, Università di Roma La Sapienza（罗马第一大学物理系及意大利国家核物理研究所罗马分部）；Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati（意大利国家核物理研究所弗拉斯卡蒂国家实验室）；LAPTh, Université Savoie Mont-Blanc et CNRS（萨瓦蒙布朗大学与法国国家科学研究中心拉普特实验室）
