Scalar dark matter interpretation of the DAMPE data with U(1) gauge interactions

Recently, DAMPE experiment released the new measurement of the total cosmic $e^{+}{e}^{-}$ flux between 25 GeV and 4.6 TeV which indicates a spectral softening at around 0.9 TeV and a tentative peak at around 1.4 TeV. We utilize the scalar dark matter (DM) annihilation scenario to explain the DAMPE peak by extending $G_{SM}\equiv SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y$ with additional $U(1)$ gauge symmetries while keeping anomaly free to generate $\chi \chi \to Z^\prime Z^\prime \to \ell\bar{\ell}\ell^\prime\overline{\ell^\prime}$,where$\chi, Z^\prime, \ell^{(^\prime)}$denotethescalarDM,thenewgaugebosonand$\ell^{(^\prime)}=e,\mu,\tau$,respectively,with$m_\chi \sim m_{Z^\prime} \sim 2 \times 1.5$(TeV)\mathrm{.}Wefirstillustratethattheminimalframework$G_{SM} \times U(1){Y^\prime}$ with the above mass choices can explain the DAMPE excess but has been excluded by LHC constraints from the $Z^{\mathrm{\prime }}$ searches. Then we study a non-minimal framework $G{SM} \times U(1){Y^\prime} \times U(1){Y^{\prime \prime}}$inwhich$U(1){Y^{\prime \prime}}$mixeswith$U(1){Y^\prime}$. We show that such a framework can interpret the DAMPE data while passing other constraints including the DM relic abundance, DM direct detection and collider bounds. We also investigate the predicted $e^{+}{e}^{-}$ spectrum in this framework and find that the mass splitting $\Delta m = m_\chi

• m_{Z’}$ should be less than about 17 GeV to produce the peak-like structure.