  The cosmic microwave background (CMB) temperature distribution measured by
the Wilkinson Microwave Anisotropy Probe (WMAP) exhibits anomalously low
correlation at large angles. Quantifying the degree to which this feature in
the temperature data is in conflict with standard Lambda-CDM cosmology is
somewhat ambiguous because of the a posteriori nature of the observation. One
physical mechanism that has been proposed as a possible explanation for the
deficit in the large-angle temperature correlations is a suppression of
primordial power on ~Gpc scales. To distinguish whether the anomaly is a signal
of new physics, such as suppressed primordial power, it would be invaluable to
perform experimental tests of the authenticity of this signal in data sets
which are independent of the WMAP temperature measurements or even other CMB
measurements. We explore the possibility of testing models of power suppression
with large-scale structure observations, and compare the ability of planned
photometric and spectroscopic surveys to constrain the power spectrum. Of the
surveys planned for the next decade, a spectroscopic redshift survey such as
BigBOSS will have a greater number of radial modes available for study, but we
find that this advantage is outweighed by the greater surface density of
high-redshift sources that will be observed by photometric surveys such as LSST
or Euclid. We also find that the ability to constrain primordial power
suppression is insensitive to the precision of the calibration of photometric
redshifts. We conclude that very-wide-area imaging surveys have the potential
to probe viable models for the missing power but that it will be difficult to
use such surveys to conclusively rule out primordial power suppression as the
mechanism behind the observed anomaly.
