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 ...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 fermdons 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.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11675100)the Recruitment Program for Young Professionals(Grant No.15Z127060004)
文摘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 fermdons 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.
