Same-sign tetralepton signature in type-Ⅱ seesaw at lepton colliders

• 作者: Xu-Hong Bai Zhi-Long Han Yi Jin Hong-Lei Li Zhao-Xia Meng
• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2022,（1）
• 所属期刊栏目: REVIEWS
• 页码范围: 21-30
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1137/ac2ed1

摘要

The same-sign tetralepton signature via the mixing of neutral Higgs bosons and their cascade decays to charged Higgs bosons is a unique signal in the type-Ⅱ seesaw model with the mass spectrum MA0 ≌ MH0 ＞ MH± ＞ MH±±.In this study,we investigate this signature at future lepton colliders,such as the ILC,CLIC,and MuC.Direct searches for doubly charged scalar H±± at the LHC have excluded MH±± ＜ 350(870) GeV in the H±± → W±W±(e±e±) decay mode.Therefore,we choose Ma0 =400,600,1000,1500 GeV as our benchmark scenarios.Constrained by direct search,H±± → W±W± is the only viable decay mode for MA0 =400 GeV at the√s =1 TeV ILC.With an integrated luminosity L =8 ab-1,the promising region,with approximately 150 signal events,corresponds to a narrow band in the range of 10-4 GeV ≤ vA ≤ 10-2 GeV.Meanwhile,for MA0 =600 GeV at the /s =1.5 TeV CLIC,approximately 10 signal events can be produced with L =2.5 ab-1.For heavier triplet scalars Ma0 ≥ 870 GeV,although the H±± → e±e± decay mode is allowed,the cascade decays are suppressed.A maximum event number ～ 16 can be obtained at approximately v△ ～ 4× 10-4 GeV and λ4 ～ 0.26 for MA0 =1000 GeV with L =5 ab-1 at the √s =3 TeV CLIC.Finally,we find that this signature is not promising for MA0 =1500 GeV at the √s =6 TeV MuC.Based on the benchmark scenarios,we also study the observability of this signature.In the H±± → W±W±(e±e±) mode,one can probe Ma0 ≤ 800(1160) GeV at future lepton colliders.