CP violation in multibody decays of beauty baryons

Gauthier Durieux

Published 2016-08-10Version 1

Beauty baryons are being observed in large number in the LHCb detector. The rich kinematics of their multibody decays are therefore becoming accessible and provide us with new opportunities to search for CP violation. We analyse the angular distributions of some three- and four-body decays of spin-$1/2$ baryons using the Jacob-Wick helicity formalism. The asymmetries that provide access to small differences of CP-odd phases between decay amplitudes of identical CP-even phases are notably discussed. The understanding gained on processes featuring specific resonant intermediate states allows us to establish which asymmetries are relevant for what purpose. It is for instance shown that some CP-odd angular asymmetries measured by the LHCb collaboration in the $\Lambda_b \to \Lambda\,\varphi \to p\,\pi\, K^+ K^-$ decay are expected to vanish identically.