Production and constraints for a massive dark photon at electron-positron colliders

• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2020,（2）
• 页码范围: 62-71
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1137/44/2/023105

摘要

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-→ q(q)A'and e+e-→ q(q)Φ (q =u,d,c,s and b quarks) are discussed.We focus on the study of the invisible A'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 √s =91.2 GeV and 240 GeV.With CEPC running at √s =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/ √B =2σ,3σ and 5σ are presented.