Spin-one dark matter and gamma ray signals from the galactic center

In this work we study the possibility that the gamma ray excess (GRE) at the Milky Way galactic center come from the annihilation of dark matter with a $(1,0)\oplus(0,1)$ space-time structure (spin-one dark matter, SODM). We calculate the production of prompt photons from initial state radiation, internal bremsstrahlung, final state radiation including the emission from the decay products of the $\mu, \tau$ or hadronization of quarks. Next we study the delayed photon emission from the inverse Compton scattering (ICS) of electrons (produced directly or in the prompt decay of $\mu, \tau$ leptons or in the hadronization of quarks produced in the annihilation of SODM) with the cosmic microwave background or starlight. All these mechanisms yield significant contributions only for Higgs resonant exchange, i.e. for $M\approx M_{H}/2$, and the results depend on the Higgs scalar coupling to SODM, $g_{s}$. The dominant mechanism at the GRE bump is the prompt photon production in the hadronization of $b$ quarks produced in $\bar{D}D\to \bar{b}b$, whereas the delayed photon emission from the ICS of electrons coming from the hadronization of $b$ quarks produced in the same reaction dominates at low energies ($\omega < 0.3~ GeV$) and prompt photons from $c$ and $\tau$, as well as from internal bremsstrahlung, yield competitive contributions at the end point of the spectrum ($\omega \ge 30 ~GeV$). Taking into account all these contributions, our results for photons produced in the annihilation of SODM are in good agreement with the GRE data for $g_{s}\in [0.98, 1.01] \times 10^{-3}$ and $M\in [62.470,62.505]~GeV$.
Comment: 24 pages, new sections added, version to appear in JHEP