Constraining the Baryon-Dark Matter Relative Velocity with the   Large-Scale 3-Point Correlation Function of the SDSS BOSS DR12 CMASS Galaxies
  We search for a galaxy clustering bias due to a modulation of galaxy number with the baryon-dark matter relative velocity resulting from recombination-era physics. We find no detected signal and place the constraint $b_v < 0.01$ on the relative velocity bias for the CMASS galaxies. This bias is an important potential systematic of Baryon Acoustic Oscillation (BAO) method measurements of the cosmic distance scale using the 2-point clustering. Our limit on the relative velocity bias indicates a systematic shift of no more than $0.3\%$ rms in the distance scale inferred from the BAO feature in the BOSS 2-point clustering, well below the $1\%$ statistical error of this measurement. This constraint is the most stringent currently available and has important implications for the ability of upcoming large-scale structure surveys such as DESI to self-protect against the relative velocity as a possible systematic. 
Zachary Slepian, Daniel J. Eisenstein, Jonathan A. Blazek, Joel R.   Brownstein, Chia-Hsun Chuang, H\'ector Gil-Mar\'in, Shi...
astro-ph.CO