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Abstract:
Approximately a quarter of the energy density of the Universe consists of Dark Matter (DM). A new stable particle in an extension of the Standard Model is a good candidate for DM, and thermal freeze-out scenario is one of the most attractive scenarios for the production of particle DM. Indirect detection experiments of DM started to be sensitive to the annihilation of DM whose mass is O(1-100) TeV. Assuming thermal freeze-out scenario, heavier thermal relic DM requires a larger coupling to be consistent with the observed relic abundance. One natural way to accommodate such a large coupling is to assume that DM is a composite particles from new strong dynamics.
In this seminar, I will introduce a DM model based on QCD-like SU(N) gauge theory with electroweakly interacting dark quarks. In particular, we focus on meson-like particles (dark pions) arising from chiral symmetry breaking in the new QCD-like sector. The lightest G-parity odd dark pion is stable and can be a good candidate for DM.
We investigate mass spectra of dark pions and annihilation channels of DM which mainly contribute to the relic abundance. We find that the mass term of the dark quarks affects the mass spectrum, and masses of DM and heavier G-parity even dark pions tend to be degenerate. In this case, annihilation processes which are kinematically forbidden in zero-temperature contribute to the relic abundance of DM in our setup. Taking such forbidden annihilation processes into account, we find that the DM model realizes heavy DM whose mass is O(1-100) TeV. I will also discuss the Sommerfeld effect on annihilation of dark pions.
Online Meeting Room：https://meeting.tencent.com/dm/ti77iypOtuur
ID: 563505654