Abstract
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 $\chi, Z^\prime, \ell^{(^\prime)}$ denote the scalar DM, the new gauge boson and $\ell^{(^\prime)}=e,\mu,\tau$, respectively, with $m_\chi \sim m_{Z^\prime} \sim 2 \times 1.5$ (TeV). We first illustrate that the minimal framework $G_{SM} \times U(1)_{Y^\prime}$ with the above mass choices can explain the DAMPE excess but has been excluded by LHC constraints from the $Z^\prime$ searches. Then we study a non-minimal framework $G_{SM} \times U(1)_{Y^\prime} \times U(1)_{Y^{\prime \prime}}$ in which $U(1)_{Y^{\prime \prime}}$ mixes with $U(1)_{Y^\prime}$. We show that such a framework can interpret the DAMPE data 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.
Highlights
The Dark Matter Particle Explorer (DAMPE) experiment released the new measurement of the total cosmic eþe− 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 [1,2]
We extended GSM ≡ SUð3ÞC × SUð2ÞL × Uð1ÞY with an additional gauged Uð1Þ family symmetry to generate χχ → Z0Z0 → lll0l0, where χ, Z0, and lð0Þ denote the scalar dark matter (DM), the new gauge boson, and lð0Þ 1⁄4 e, μ, τ, respectively, with mχ ∼ mZ0 ∼ 2 × 1.5 ðTeVÞ
We first illustrated that the minimal framework GSM × Uð1ÞY0 with the above mass choices can explain the DAMPE excess but has been excluded by the LHC constraints from the Z0 searches
Summary
The Dark Matter Particle Explorer (DAMPE) experiment released the new measurement of the total cosmic eþe− 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 [1,2]. Since no confirmed source has been established, in this paper, we assume DM to annihilate democratically into eþe−, μþμ−, and τþτ− to explain the DAMPE data. This interpretation requires the following four conditions: (i) Indirect detection (ID): large hσvi0 ≳1×10−26 cm3=s with v ∼ 10−3c in today’s Universe, coinciding with other DM ID constraints. There are many possible ways for the charge assignments to guarantee anomaly cancelation, we adopt the minimal setting to predict equal eþe−, μþμ−, and τþτ− coupling strengths for the new gauge boson, which was first proposed in Ref. The term λ0χsððφÃχφsÞ2 þ H:c:Þ in Eq (2) can generate an important
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