Towards a self-consistent analysis of the anisotropic galaxy two- and
  three-point correlation functions on large scales: application to mock galaxy
  catalogues
  We establish a practical method for the joint analysis of anisotropic galaxy
two- and three-point correlation functions (2PCF and 3PCF) on the basis of the
decomposition formalism of the 3PCF using tri-polar spherical harmonics. We
perform such an analysis with MultiDark Patchy mock catalogues to demonstrate
and understand the benefit of the anisotropic 3PCF. We focus on scales above
$80 h^{-1}\,{\rm Mpc}$, and use information from the shape and the baryon
acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density
field reconstruction to increase the signal-noise ratio of BAO in the 2PCF
measurement, but not in the 3PCF measurement. In particular, we study in detail
the constraints on the angular diameter distance and the Hubble parameter. We
build a model of the bispectrum or 3PCF that includes the nonlinear damping of
the BAO signal in redshift space. We carefully account for various
uncertainties in our analysis including theoretical models of the 3PCF, window
function corrections, biases in estimated parameters from the fiducial values,
the number of mock realizations to estimate the covariance matrix, and bin
size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole
components shows a $30\%$ a nd $20\%$ improvement in Hubble parameter
constraints before and after reconstruction of the 2PCF measurements,
respectively, compared to the 2PCF analysis alone. This study clearly shows
that the anisotropic 3PCF increases cosmological information from galaxy
surveys and encourages further development of the modeling of the 3PCF on
smaller scales than we consider.
