  Ultracold CH radicals promise a fruitful testbed for probing quantum-state
controllable organic chemistry. In this work, we calculate CH vibrational
branching ratios (VBRs) and rotational branching ratios (RBRs) with ground
state mixing. We subsequently use these values to inform optical cycling
proposals and consider two possible radiative cooling schemes using the
$X^{2}\Pi \leftarrow A^{2}\Delta$ and $X^{2}\Pi \leftarrow B^{2}\Sigma^{-}$
transitions. As a first step towards laser cooled CH, we characterize the
effective buffer gas cooling of this species and produce $\sim5\times10^{10}$
CH molecules per pulse with a rotational temperature of 2(1) K and a
translational temperature of 7(2) K. We also determine the CH-helium
collisional cross section to be $2.4(8)\times10^{-14}$ cm$^{2}$. This value is
crucial to correctly account for collisional broadening and accurately extract
the in-cell CH density. These cold CH molecules mark an ideal starting point
for future laser cooling and trapping experiments and tests of cold organic
chemistry.
