Dark sector may couple to the Standard Model via one or more mediator particles.We discuss two types of mediators:the dark photon A’ and the dark scalar mediator Φ .The total cross-sections and various differential ...Dark sector may couple to the Standard Model via one or more mediator particles.We discuss two types of mediators:the dark photon A’ and the dark scalar mediator Φ .The total cross-sections and various differential distributions of the processes e+e-→qqA’ and e+e→qqφ（q=u,d,c,s and b quarks） are discussed.We focus on the study of the invisible due to the cleaner background at future e+e-colliders.It is found that the kinematic distributions of the two-jet system could be used to identify（or exclude） the dark photon and the dark scalar mediator,as well as to distinguish between them.We further study the possibility of a search for dark photons at a future CEPC experiment with s1/2=91.2 GeV and 240 GeV.With CEPC running at s1/2=91.2 GeV,it would be possible to perform a decisive measurement of the dark photon（20 GeV <mA’ <60 GeV） in less than one operating year.The lower limits of the integrated luminosity for the significance S/B1/2=2σ,3σ and 5σ are presented.展开更多
基金supported in part by the National Natural Science Foundation of China(11875179,11325525,11635009,11775130,11905112)the Natural Science Foundation of Shandong Province(ZR2017MA002,ZR2019QA012)the Fundamental Research Funds of Shandong University(2019GN038)
文摘Dark sector may couple to the Standard Model via one or more mediator particles.We discuss two types of mediators:the dark photon A’ and the dark scalar mediator Φ .The total cross-sections and various differential distributions of the processes e+e-→qqA’ and e+e→qqφ（q=u,d,c,s and b quarks） are discussed.We focus on the study of the invisible due to the cleaner background at future e+e-colliders.It is found that the kinematic distributions of the two-jet system could be used to identify（or exclude） the dark photon and the dark scalar mediator,as well as to distinguish between them.We further study the possibility of a search for dark photons at a future CEPC experiment with s1/2=91.2 GeV and 240 GeV.With CEPC running at s1/2=91.2 GeV,it would be possible to perform a decisive measurement of the dark photon（20 GeV <mA’ <60 GeV） in less than one operating year.The lower limits of the integrated luminosity for the significance S/B1/2=2σ,3σ and 5σ are presented.
