Title: Light vectors coupled to bosonic currents Show Chinese title

Title: 轻矢量与玻色子电流耦合

Abstract: New spin-1 particles with masses below the weak scale are present in many theories of beyond Standard Model (SM) physics. In this work, we extend previous analyses by systematically considering the couplings of such a vector to the bosonic sector of the SM, focusing on models that lead to mass-mixing with the Z boson. These couplings generically lead to enhanced emission of the vector's longitudinal mode, both in Higgs decays and in flavor changing meson decays. We present bounds in the SM+X effective theory and investigate their model-dependence. For the case of Higgs decays, we point out that tree-level vector emission is, depending on the model, not always enhanced, affecting the constraints. For meson decays, which are the dominant constraints at small vector masses, we find that while $B$ decay constraints can be weakened by fine-tuning UV parameters, it is generically difficult to suppress the stringent constraints from kaon decays. Show Chinese abstract

Abstract: 质量低于弱尺度的新自旋-1粒子存在于许多超出标准模型（SM）物理的理论中。 在本工作中，我们通过系统地考虑此类矢量与标准模型玻色子部分的耦合，扩展了之前的分析，重点研究导致与Z玻色子质量混合的模型。 这些耦合通常会导致矢量纵向模式的增强发射，既在希格斯衰变中，也在味改变介子衰变中。 我们给出了SM+X有效理论中的限制，并研究了其模型依赖性。 对于希格斯衰变的情况，我们指出，根据模型的不同，树级矢量发射并不总是增强的，这会影响约束条件。 对于介子衰变，这是小矢量质量下的主要约束，我们发现虽然$B$衰变约束可以通过微调紫外参数来减弱，但一般来说，抑制来自K介子衰变的严格约束是困难的。