Hubble constant difference between CMB lensing and BAO measurements
  We apply a tension metric $Q_\textrm{UDM}$, the update difference in mean
parameters, to understand the source of the difference in the measured Hubble
constant $H_0$ inferred with cosmic microwave background lensing measurements
from the Planck satellite ($H_0=67.9^{+1.1}_{-1.3}\, \mathrm{km/s/Mpc}$) and
from the South Pole Telescope ($H_0=72.0^{+2.1}_{-2.5}\, \mathrm{km/s/Mpc}$)
when both are combined with baryon acoustic oscillation (BAO) measurements with
priors on the baryon density (BBN). $Q_\textrm{UDM}$ isolates the relevant
parameter directions for tension or concordance where the two data sets are
both informative, and aids in the identification of subsets of data that source
the observed tension. With $Q_\textrm{UDM}$, we uncover that the difference in
$H_0$ is driven by the tension between Planck lensing and BAO+BBN, at
probability-to-exceed of 6.6%. Most of this mild tension comes from the galaxy
BAO measurements parallel to the line of sight. The redshift dependence of the
parallel BAOs pulls both the matter density $\Omega_m$ and $H_0$ high in
$\Lambda$CDM, but these parameter anomalies are usually hidden when the BAO
measurements are combined with other cosmological data sets with much stronger
$\Omega_m$ constraints.
