A Constraint On the Integrated Mass Power Spectrum out to z = 1100 from
  Lensing of the Cosmic Microwave Background
  The temperature fluctuations and polarization of the Cosmic Microwave
Background (CMB) are now a well-known probe of the Universe at an infant age of
400,000 years. During the transit to us from the surface of last scattering,
the CMB photons are expected to undergo modifications induced by the
intervening large-scale structure. Among the expected secondary effects is the
weak gravitational lensing of the CMB by the foreground dark matter
distribution. We derive a quadratic estimator that uses the non-Gaussianities
generated by the lensing effect at the four-point function level to extract the
power spectrum of lensing potential fluctuations integrated out to z ~ 1100
with peak contributions from potential fluctuations at z of 2 to 3. Using WMAP
7-year temperature maps, we report the first direct constraints of this lensing
potential power spectrum and find that it has an amplitude of A_L = 0.96 +/-
0.60, 1.06 +/- 0.69 and 0.97 +/- 0.47 using the W, V and W+V bands,
respectively.
