Hint of a truncated primordial spectrum from the CMB large-scale
  anomalies
  Several satellite missions have uncovered a series of potential anomalies in
the fluctuation spectrum of the cosmic microwave background temperature,
including: (1) an unexpectedly low level of correlation at large angles,
manifested via the angular correlation function, C(theta); and (2) missing
power in the low multipole moments of the angular power spectrum, C_ell. Their
origin is still debated, however, due to a persistent lack of clarity
concerning the seeding of quantum fluctuations in the early Universe. A likely
explanation for the first of these appears to be a cutoff, k_min=(3.14 +/-
0.36) x 10^{-4} Mpc^{-1}, in the primordial power spectrum, P(k). Our goal in
this paper is twofold: (1) we examine whether the same k_min can also
self-consistently explain the missing power at large angles, and (2) we confirm
that the of this cutoff in P(k) does not adversely affect the remarkable
consistency between the prediction of Planck-LCDM and the Planck measurements
at ell > 30. We use the publicly available code CAMB to calculate the angular
power spectrum, based on a line-of-sight approach. The code is modified
slightly to include the additional parameter (i.e., k_min) characterizing the
primordial power spectrum. In addition to this cutoff, the code optimizes all
of the usual standard-model parameters. In fitting the angular power spectrum,
we find an optimized cutoff, k_min = 2.04^{+1.4}_{-0.79} x 10^{-4} Mpc^{-1},
when using the whole range of ell's, and k_min=3.3^{+1.7}_{-1.3} x 10^{-4}
Mpc^{-1}, when fitting only the range ell < 30, where the Sachs-Wolfe effect is
dominant. These are fully consistent with the value inferred from C(theta),
suggesting that both of these large-angle anomalies may be due to the same
truncation in P(k).
