暗电荷共轭与来自D⁰混合及无质量暗光子稀有衰变的互补约束
Dark Charge Conjugation and Complementary Constraints from $D^0$ Mixing and Rare Decays with Massless Dark Photons
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中文总结 AI 辅助
该研究探究暗电荷共轭对D⁰稀有衰变的组织作用，结合D⁰混合及相关稀有衰变约束，揭示中性粲介子混合与稀有衰变在探测味改变相互作用时的互补性。
中文摘要 AI 辅助
我们研究暗电荷共轭如何组织涉及无质量暗光子的D⁰稀有衰变，以及这些衰变如何与中性粲介子混合互补，以约束共同的味改变相互作用。在具有实赝标量媒介子的简化框架内，D⁰→γ_Dγ_D探测保持𝒞_D的门户，而D⁰→γγ_D探测与𝒞_D破缺相关的门户。由于这两个衰变道与D⁰混合共享相同的味归一化和媒介子传播子，味依赖可被解析消除，将混合约束转化为对不可见衰变率的直接上限。结合来自混合、不可见衰变及单暗光子道的当前约束，我们在媒介子参数空间中识别出混合主导区域与不可见衰变主导区域之间的过渡。一旦味归一化固定为混合与不可见衰变允许的最大值，单暗光子搜索即可对与𝒞_D破缺相关的门户给出条件上限。这些结果表明，中性介子混合与稀有粲衰变在探测带无质量暗区的味改变相互作用时，存在一种对称性分辨的互补性。
英文摘要
We investigate how dark charge conjugation organizes rare $D^0$ decays involving a massless dark photon and how these decays complement neutral charm mixing in constraining a common flavor changing interaction. Within a simplified framework with a real pseudoscalar mediator, $D^0\toγ_{\mathrm D}γ_{\mathrm D}$ probes the portal that preserves $\mathcal{C}_{\mathrm D}$, whereas $D^0\toγγ_{\mathrm D}$ probes the portal associated with $\mathcal{C}_{\mathrm D}$ breaking. Because the two decay channels and $D^0$ mixing share the same flavor normalization and mediator propagator, the flavor dependence can be eliminated analytically, converting the mixing constraint into a direct upper bound on the invisible decay rate. Combining current constraints from mixing, invisible decay, and the single dark photon channel, we identify a transition between regions dominated by mixing and regions dominated by invisible decay in mediator parameter space. The single dark photon search then yields conditional upper limits on the portal associated with $\mathcal{C}_{\mathrm D}$ breaking once the flavor normalization is fixed at its maximal value allowed by mixing and invisible decay. These results demonstrate a symmetry resolved complementarity between neutral meson mixing and rare charm decays in probing flavor changing interactions with a massless dark sector.
