Recently, the Dark Matter Particle Explorer (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 a scalar dark matter (DM) model to explain the DAMPE peak by $\chi \chi \to Z^{\prime }{Z}^{\prime }\to \ell \overline{\ell }{\ell }^{\prime }\overline{{\ell }^{\prime }}$ with an additional anomaly-free gauged $U(1)$ family symmetry, in which $\chi$, $Z^{\prime }$, and ${\ell }^{(\prime )}$ denote, respectively, the scalar DM, the new gauge boson, and ${\ell }^{(\prime )}=e$, $\mu$, $\tau$ with $m_{\chi }\sim m_{Z^{\prime }}\sim 2\times 1.5(\mathrm{TeV})$. We first illustrate that the minimal framework $G_{\mathrm{SM}}\times U(1{)}_{Y^{\prime }}$ with the above mass choices can explain the DAMPE excess, which, however, be excluded by LHC constraints from the $Z^{\prime }$ searches. Then, we study a nonminimal framework $G_{\mathrm{SM}}\times U(1{)}_{Y^{\prime }}\times U(1{)}_{Y^{\prime \prime }}$ in which $U(1{)}_{Y^{\prime \prime }}$ mixes with $U(1{)}_{Y^{\prime }}$. We show that such a framework can interpret the DAMPE data and at the same time survive all 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 $\mathrm{\Delta }m=m_{\chi }-m_{Z^{\prime \prime }}$ should be less than about 17 GeV to produce the peaklike structure.

• Received 20 February 2018

DOI:https://doi.org/10.1103/PhysRevD.97.095011

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society