Gravitational Vector Dark Matter

Abstract

A new dark sector consisting of a pure non-abelian gauge theory has no renormalizable interaction with SM particles, and can thereby realise gravitational Dark Matter (DM). Gauge interactions confine at a scale ${\Lambda }_{\mathrm{DM}}$ giving bound states with typical lifetimes $\tau \sim M_{\mathrm{Pl}}^4/{\Lambda }_{\mathrm{DM}}^5$ that can be DM candidates if ${\Lambda }_{\mathrm{DM}}$ is below 100 TeV. Furthermore, accidental symmetries of group-theoretical nature produce special gravitationally stable bound states. In the presence of generic Planck-suppressed operators such states become long-lived: SU$(N)$ gauge theories contain bound states with $\tau \sim M_{\mathrm{Pl}}^8/{\Lambda }_{\mathrm{DM}}^9$; even longer lifetimes $\tau =(M_{\mathrm{Pl}}/{\Lambda }_{\mathrm{DM}}{)}^{2N-4}/{\Lambda }_{\mathrm{DM}}$ arise from SO$(N)$ theories with $N\ge 8$, and possibly from $F_4$ or $E_8$. We compute their relic abundance generated by gravitational freeze-in and by inflationary fluctuations, finding that they can be viable DM candidates for ${\Lambda }_{\mathrm{DM}}\gtrsim 10^{10}$ GeV.

21 pages; to appear in JHEP