Cosmological constraints from the tomographic cross-correlation of DESI
  Luminous Red Galaxies and Planck CMB lensing
  We use luminous red galaxies selected from the imaging surveys that are being
used for targeting by the Dark Energy Spectroscopic Instrument (DESI) in
combination with CMB lensing maps from the Planck collaboration to probe the
amplitude of large-scale structure over $0.4\le z\le 1$. Our galaxy sample,
with an angular number density of approximately $500\,\mathrm{deg}^{-2}$ over
18,000 sq.deg., is divided into 4 tomographic bins by photometric redshift and
the redshift distributions are calibrated using spectroscopy from DESI. We fit
the galaxy autospectra and galaxy-convergence cross-spectra using models based
on cosmological perturbation theory, restricting to large scales that are
expected to be well described by such models. Within the context of
$\Lambda$CDM, combining all 4 samples and using priors on the background
cosmology from supernova and baryon acoustic oscillation measurements, we find
$S_8=\sigma_8(\Omega_m/0.3)^{0.5}=0.73\pm 0.03$. This result is lower than the
prediction of the $\Lambda$CDM model conditioned on the Planck data. Our data
prefer a slower growth of structure at low redshift than the model predictions,
though at only modest significance.
