We explore the cosmological implications of the clustering wedges , \xi _ { \perp } ( s ) and \xi _ { \parallel } ( s ) , of the CMASS Data Release 9 ( DR9 ) sample of the SDSS-III Baryon Oscillation Spectroscopic Survey ( BOSS ) .
These clustering wedges are defined by averaging the full two-dimensional correlation function , \xi ( \mu,s ) , over the ranges 0 < \mu < 0.5 and 0.5 < \mu < 1 , respectively .
These measurements allow us to constrain the parameter combinations D _ { A } ( z ) / r _ { s } ( z _ { d } ) = 9.03 \pm 0.21 and cz / ( r _ { s } ( z _ { d } ) H ( z ) ) = 12.14 \pm 0.43 at the mean redshift of the sample , z = 0.57 .
We combine the information from the clustering wedges with recent measurements of CMB , BAO and type Ia supernovae to obtain constraints on the cosmological parameters of the standard \Lambda CDM model and a number of potential extensions .
The information encoded in the clustering wedges is most useful when the dark energy equation of state is allowed to deviate from its standard \Lambda CDM value .
The combination of all datasets shows no evidence of a deviation from a constant dark energy equation of state , in which case we find w _ { DE } = -1.013 \pm 0.064 , in complete agreement with a cosmological constant .
We explore potential deviations from general relativity by constraining the growth rate f ( z ) = { d } \ln D ( a ) / { d } \ln a , in which case the combination of the CMASS clustering wedges with CMB data implies f ( z = 0.57 ) = 0.719 _ { -0.096 } ^ { +0.092 } , in accordance with the predictions of GR .
Our results clearly illustrate the additional constraining power of anisotropic clustering measurements with respect to that of angle-averaged quantities .