An analytic approach to baryon acoustic oscillations
  The fitting formula for the location of the first acoustic peak in the matter
power spectrum is revised. We discuss the physics that leads to baryon acoustic
oscillations: the recombination history, the tight coupling approximation and
the velocity overshoot effect. A new fitting formula is proposed, which is in
accordance within 5% with numerical results for a suitable range of
cosmological parameters, whereas previous results yield deviations of up to
20%. The crucial improvement turns out to be the accuracy of the recombination
history.
