The hubble rate trouble: an effective field theory of dark matter

Abstract The Hubble constant inferred from the 6-parameter fit to CMB power spectrum conflicts with value obtained direct measurements via type Ia supernova and Cepheids observations. We write down effective operators involving spin-0, spin-1/2, spin-1 dark matter that lead relativistic production of particles at early times, consequently an increase in number degrees freedom. This mechanism which is amenable CMB, BBN, structure formation observables can sufficiently raise derived reconcile local probes constant. alone increases $$H_0$$ H 0 up $$70\, \textrm{km}\, \textrm{s}^{-1} \, \textrm{Mpc}^{-1}$$ 70 km s - 1 Mpc , help a Phantom-like cosmology, reach $$H_0 \simeq $$ ≃ 71–73 $$\textrm{km} \,\textrm{s}^{-1} . Lastly, we outline region parameter space reproduces while obeying all relevant constraints.