Nuclear Physics B ( IF 2.8 ) Pub Date : 2020-11-12 , DOI: 10.1016/j.nuclphysb.2020.115237 Shao-Long Chen , Amit Dutta Banik , Zhaofeng Kang , Qin Qin , Yoshihiro Shigekami
Rare B meson decays offer an opportunity to probe a light hidden boson. In this work we explore a new channel () followed by a cascade decay of into an invisible (neutrino or dark matter) or charged lepton pair (). The study is based on a simplified effective model where the down quark sector has tiny flavor-changing neutral current couplings with . For the first time, we calculate at the leading power of and . Confronting with the strong constraints from semi-invisible decays of B meson, we find that the branching ratio for can be larger than its Standard Model background prediction, leaving a large room for new physics, in particular for light dark matter. Additionally, the branching ratio for can also be sizable when the corresponding flavor violating coupling to quarks is of the axial-vector type. On the other hand, the predicted branching ratios of and are severely constrained by the experimental measurements.
中文翻译:
B q → γZ '中的Z '玻色子的风味变化特征
罕见的B介子衰变提供了探测暗光的机会玻色子。在这项工作中,我们探索了一个新的渠道 (),然后是 变成看不见的(中微子或暗物质)或带电的轻子对 ()。这项研究基于简化的有效模型,在该模型中,下夸克区具有微小的变味中性电流耦合,。我们第一次计算 在...的领导力 和 。面对B介子的半隐形衰变的强约束,我们发现可以比标准模型的背景预测大,这为新物理,尤其是浅暗物质留有很大的空间。此外, 当违反相应的风味时,也可以调整大小 与夸克的耦合是轴向矢量类型。另一方面,预测的分支比为 和 受到实验测量的严格限制。