Scalar dark matter explanation of the DAMPE data in the minimal left-right symmetric model

The left-right symmetric model (LRSM) is an attractive extension of the Standard Model (SM) that can address the origin of parity violation in the SM electroweak interactions, generate tiny neutrino masses, accommodate dark matter (DM) candidates, and provide a natural framework for baryogenesis through leptogenesis. In this work, we utilize the minimal LRSM to study the recently reported DAMPE results of the cosmic e⁺e^- spectrum, which exhibits a tentative peak around 1.4 TeV, while satisfying the current neutrino data. We propose to explain the DAMPE peak with a complex scalar DM χ in two scenarios: (1) ${χ}{{χ}}*{→}{H}₁⁺⁺{H}₁^{{-}{-}}{→}{{}}ᵢ⁺{{}}ᵢ⁺{{}}ⱼ^{{-}}{{}}ⱼ^{{-}}$, and (2) ${χ}{{χ}}*{→}{H}ₖ⁺⁺{H}ₖ^{{-}{-}}{→}{{}}ᵢ⁺{{}}ᵢ⁺{{}}ⱼ^{{-}}{{}}ⱼ^{{-}}$ accompanied by ${χ}{{χ}}*{→}{{0ex}{0ex}}{H}₁⁺{H}₁^{{-}}{→}{{}}ᵢ⁺{{ν}}_{{{}}ᵢ}{{}}ⱼ^{{-}}{{ν}}_{{{}}ⱼ}$, with ${{}}i,j=e$, ${μ}$, ${τ}$ and $k=1$, 2. We fit the theoretical prediction of the ${e}⁺{e}^{{-}}$ spectrum to relevant experimental data to determine the scalar mass spectrum favored by the DAMPE excess. We also consider various constraints from theoretical principles and collider experiments, as well as DM relic density and direct search experiments. We find that there is ample parameter space to interpret the DAMPE data while also passing the constraints. On the other hand, our explanations usually imply the existence of other new physics at an energy scale ranging from 10⁷ to 10¹¹ GeV. Collider tests of our explanations are also discussed.