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Dark Matter Candidates

Hypothetical particles that make up the majority of the universe's mass, interacting weakly with ordinary matter, explored through various theoretical models.
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The statement of the theorem

Define the Lagrangian density L\mathcal{L} for a generic Weakly Interacting Massive Particle (WIMP) candidate χ\chi interacting with the Standard Model fields Φ\Phi: L=LSM+Lχ+Lint\mathcal{L} = \mathcal{L}_{SM} + \mathcal{L}_{\chi} + \mathcal{L}_{int} where Lχ\mathcal{L}_{\chi} describes the free propagation of χ\chi (e.g., Lχ=12Tr(∂μχ∂μχ)−12mχ2Tr(χ2)\mathcal{L}_{\chi} = \frac{1}{2} \text{Tr}(\partial_{\mu} \chi \partial^{\mu} \chi) - \frac{1}{2} m_{\chi}^2 \text{Tr}(\chi^2)). The interaction term Lint\mathcal{L}_{int} must be suppressed relative to the SM interactions, typically involving couplings gχg_{\chi} to SM gauge bosons or fermions: Lint=gχχψˉψ+12gVχ2 Tr(FμνFμν)+…\mathcal{L}_{int} = g_{\chi} \chi \bar{\psi} \psi + \frac{1}{2} g_{V} \chi^2 \ \text{Tr}(F_{\mu\nu} F^{\mu\nu}) + \dots The relic density Ωχh2\Omega_{\chi} h^2 is determined by solving the Boltzmann equation for the particle number density nχ(t)n_{\chi}(t) in the early universe.
Source: Wikipedia