Constraints on massive neutrinos from the pairwise kinematic
  Sunyaev-Zel'dovich effect
  We present the mean pairwise momentum of clusters, as observed through the
kinematic Sunvaev-Zel'dovich (kSZ) effect, as a novel probe of massive
neutrinos. We find that kSZ measurements with current and upcoming surveys will
provide complementary constraints on the sum of neutrino masses from large
scale structure and will improve on Planck satellite measurements of the
primordial cosmic microwave background (CMB) and CMB lensing. Central to the
constraints is a distinctive scale dependency of the kSZ neutrino signature on
the mean pairwise momentum of clusters that we do not expect to be mirrored in
systematic effects that change the overall amplitude of the signal, like the
cluster optical depth.
  Assuming a minimal $\Lambda$CDM cosmology including massive neutrinos with
Planck primordial CMB priors combined with conservative kSZ specifications, we
forecast $68%$ upper limits on the neutrino mass sum of $290$ meV, $220$ meV,
$96$ meV for "Stage II" (ACTPol + BOSS), "Stage III" (Advanced ACTPol + BOSS),
and "Stage IV" (CMB-S4 + DESI) surveys respectively, compared to the Planck
alone forecast of 540 meV. These forecasts include the ability to
simultaneously constrain the neutrino mass sum and the mass-averaged optical
depth of the cluster sample in each redshift bin. If the averaged optical depth
of clusters can be measured with few percent accuracy and a lower limiting mass
is assumed, the projected kSZ constraints improve further to $120$ meV, $90$
meV and $33$ meV (Stage II, III and IV). These forecasts represent a
conservative estimate of neutrino constraints using cross-correlations of
arcminute-resolution CMB measurements and spectroscopic galaxy surveys. More
information relevant for neutrino constraints is available from these surveys,
such as galaxy clustering, weak lensing, and CMB temperature and polarization.
