Abstract
An analysis of the bottom baryon decay $Λb→J/ψ(→μ^+μ^−)Λ(→pπ^−)$ is performed to measure the $Λb$ polarization and three angular parameters in data from $pp$ collisions at $\sqrt s=7$ and $8 TeV$, collected by the CMS experiment at the Large Hadron Collider. The $Λb$ polarization is measured to be $0.00±0.06(stat)±0.06(syst)$ and the parity-violating asymmetry parameter is determined to be $0.14±0.14(stat)±0.10(syst)$. The measurements are compared to various theoretical predictions, including those from perturbative quantum chromodynamics.