Constraining higher-order parameters for primordial non-Gaussianities
  from power spectra and bispectra of imaging survey
  We investigate the statistical power of higher-order statistics and
cross-correlation statistics to constrain the primordial non-Gaussianity from
the imaging surveys. In particular, we consider the local-type primordial non-
Gaussianity and discuss how well one can tightly constrain the higher-order
non-Gaussian parameters ($g_{\rm NL}$ and $\tau_{\rm NL}$) as well as the
leading order parameter $f_{\rm NL}$ from the halo/galaxy clustering and weak
gravitational lensing measurements. Making use of a strong scale-dependent
behavior in the galaxy/halo clustering, Fisher matrix analysis reveals that the
bispectra can break the degeneracy between non-Gaussian parameters ($f_{\rm
NL}$, $g_{\rm NL}$ and $\tau_{\rm NL}$) and this will give simultaneous
constraints on those three parameters. The combination of cross-correlation
statistics further improves the constraints by factor of 2. As a result,
upcoming imaging surveys like the Large Synoptic Survey Telescope have the
potential to improve the constraints on the primordial non-Gaussianity much
tighter than those obtained from the CMB measurement by Planck, giving us an
opportunity to test the single-sourced consistency relation, $\tau_{\rm NL} \ge
(36/25) f_{\rm NL}^2$.
