Redshift-Space Distortions in Lagrangian Perturbation Theory
  We present the one-loop 2-point function of biased tracers in redshift space
computed with Lagrangian perturbation theory, including a full resummation of
both long-wavelength (infrared) displacements and associated velocities. The
resulting model accurately predicts the power spectrum and correlation function
of halos and mock galaxies from two different sets of N-body simulations at the
percent level for quasi-linear scales, including the damping of the baryon
acoustic oscillation signal due to the bulk motions of galaxies. We compare
this full resummation with other, approximate, techniques including the moment
expansion and Gaussian streaming model. We discuss infrared resummation in
detail and compare our Lagrangian formulation with the Eulerian theory
augmented by an infrared resummation based on splitting the input power
spectrum into "wiggle" and "no-wiggle" components. We show that our model is
able to recover unbiased cosmological parameters in mock data encompassing a
volume much larger than what will be available to future galaxy surveys. We
demonstrate how to efficiently compute the resulting expressions numerically,
making available a fast Python code capable of rapidly computing these
statistics in both configuration and Fourier space.
