Quasi-degenerate dark matter for DAMPE excess and 3.5 keV line

• 来源期刊: 中国科学:物理学 力学 天文学（英文版）
• 年，卷（期）: 2018,（10）
• 页码范围: 30-35
• 页数: 6页
• 语种: 英文

摘要

We propose a quasi-degenerate dark matter scenario to simultaneously explain the 1.4 TeV peak in the high-energy cosmic-ray electron-positron spectrum reported by the DAMPE collaboration very recently and the 3.5 keV X-ray line observed in galaxies clusters and from the Galactic centre and confirmed by the Chandra and NuSTAR satellites.We consider a dark S U(2)'× U(1)'gauge symmetry under which the dark matter is a Dirac fermion doublet composed of two S U(2)'doublets with non-trivial U(1)'charges.At the one-loop level the two dark fermion components can have a mass split as a result of the dark gauge symmetry breaking.Through the exchange of a mediator scalar doublet the two quasi-degenerate dark fermions can mostly annihilate into the electron-positron pairs at the tree level for explaining the 1.4 TeV positron anomaly,meanwhile,the heavy dark fermion can very slowly decay into the light dark fermion with a photon at the one-loop level for explaining the 3.5 keV X-ray line.Our dark fermions can be also verified in the direct detection experiments.