Unraveling dark Higgs mechanism via dark photon production at an e+e− collider

A bstract In the phenomenological study of dark photon, its mass origin is usually not of concern. However, in theoretical model construction, its mass is often generated via a dark Higgs mechanism, which leads to the presence of a light (non-decoupled) dark Higgs particle. In this work, we study the impact of such a dark Higgs particle on the collider detection of the dark photon. We focus on the process of final state dark photon radiating dark Higgs, which is called dark final state radiation (FSR). Considering the effects on both the signal cross section and the distribution of the squared missing mass, the invisible dark photon search at BaBar is reanalyzed and a new exclusion limit for invisible dark photon is presented.