Cosmological Hydrogen Recombination: influence of resonance and electron
  scattering
  In this paper we consider the effects of resonance and electron scattering on
the escape of Lyman alpha photons during cosmological hydrogen recombination.
We pay particular attention to the influence of atomic recoil, Doppler boosting
and Doppler broadening using a Fokker-Planck approximation of the
redistribution function describing the scattering of photons on the Lyman alpha
resonance of moving hydrogen atoms. We extend the computations of our recent
paper on the influence of the 3d/3s-1s two-photon channels on the dynamics of
hydrogen recombination, simultaneously including the full time-dependence of
the problem, the thermodynamic corrections factor, leading to a
frequency-dependent asymmetry between the emission and absorption profile, and
the quantum-mechanical corrections related to the two-photon nature of the
3d/3s-1s emission and absorption process on the exact shape of the Lyman alpha
emission profile. We show here that due to the redistribution of photons over
frequency hydrogen recombination is sped up by DN_e/N_e~-0.6% at z~900. For the
CMB temperature and polarization power spectra this results in
|DC_l/C_l|~0.5%-1% at l >~ 1500, and therefore will be important for the
analysis of future CMB data in the context of the PLANCK Surveyor, SPT and ACT.
The main contribution to this correction is coming from the atomic recoil
effect (DN_e/N_e~-1.2% at z~900), while Doppler boosting and Doppler broadening
partially cancel this correction, again slowing hydrogen recombination down by
DN_e/N_e~0.6% at z~900. The influence of electron scattering close to the
maximum of the Thomson visibility function at z~1100 can be neglected.
(abridged)
