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

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 M_A⁰≈M_H⁰>M_H⁺>M_H^±±.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 MHg+t<350(870) GeV in the H^±±+W^±W(±)(l^±±)decay mode.Therefore,we choose M_A⁰=400,600,1000,1500 GeV as our benchmark scenarios.Constrained by direct search,H^±±+W^±W(±)(l^±±)d=is the only viable decay mode for Mρ=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≤v△≤10^-2GeV.Meanwhile,for Mpo=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 M_A⁰■870 GeV,although the H^±± decay mode is allowed,the cascade decays are suppressed.A maximum event number~16 can be obtained at approximately v△~4×10⁴GeV and λ₁₄~0.26 for M_A⁰=1000 GeV with L=5 ab^-1 at the √s=3 TeV CLIC.Finally,we find that this signature is not promising for M_A⁰= 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(±)(l^±±)d mode,one can probe MρS 800(1160) GeV at future lepton colliders.     

Confronting the DAMPE excess with the scotogenic type-Ⅱ seesaw model

The DArk Matter Particle Explorer(DAMPE) has observed a tentative peak at E ~ 1.4 Te V in the cosmic-ray electron spectrum.In this paper,we interpret this excess in the scotogenic type-Ⅱ seesaw model.This model extends the canonical type-Ⅱ seesaw model with dark matter(DM) candidates and a loop-induced vacuum expectation value of the triplet scalars,v?,resulting in small neutrino masses naturally even for Te V scale triplet scalars.Assuming a nearby DM subhalo,the DAMPE excess can be explained by DM annihilating into a pair of triplet scalars which subsequently decay to charged lepton final states.Spectrum fitting of the DAMPE excess indicates it potentially favors the inverted neutrino mass hierarchy.We also discuss how to evade associated neutrino flux in our model.     

《文科物理——生活中的物理学》教材的特色与启示

对《文科物理——生活中的物理学》教材进行了全面深入的评介与研究.笔者通过对教材特色的分析,对我国文科物理教材的编写提出了三点建议:诸如注重人文教学、重在讲述概念、加强实例插图.