Redshift space power spectrum beyond Einstein-de Sitter kernels
  We develop a framework to compute the redshift space power spectrum (PS),
with kernels beyond Einstein-de Sitter (EdS), that can be applied to a wide
variety of generalized cosmologies. We build upon a formalism that was recently
employed for standard cosmology in Chen, Vlah & White (2020), and utilize an
expansion of the density-weighted velocity moment generating function that
explicitly separates the magnitude of the $k$-modes and their angle to the
line-of-sight direction dependencies. We compute the PS for matter and biased
tracers to 1-loop Perturbation Theory (PT) and show that the expansion has a
correct infrared and ultraviolet behavior, free of unwanted divergences. We
also add Effective Field Theory (EFT) counterterms, necessary to account for
small-scale contributions to PT, and employ an IR-resummation prescription to
properly model the smearing of the BAO due to large scale bulk flows within
Standard-PT. To demonstrate the applicability of our formalism, we apply it on
the $\Lambda$CDM and the Hu-Sawicki $f(R)$ models, and compare our numerical
results against the ELEPHANT suite of $N$-body simulations, finding very good
agreement up to $k= 0.27\, \text{Mpc}^{-1} h$ at $z=0.5$ for the first three
non-vanishing Legendre multipoles of the PS. To our knowledge, the model
presented in this work is the most accurate theoretical EFT-PT for modified
gravity to date, being the only one that accounts for beyond linear local
biasing in redshift-space. Hence, we argue our RSD modeling is a promising tool
to construct theoretical templates in order to test deviations from
$\Lambda$CDM using real data obtained from the next stage of cosmological
surveys such as DESI and LSST.
