Multibody charmless b-hadron decays

Multibody charmless b-hadron decays are a unique laboratory to probe CP violation, to look for effects of new physics and to provide insights into the hadronisation mechanism. The decay modes $\Lambda_b^0 \to \Lambda K^+ K^-$, $\Lambda_b^0 \to \Lambda K^+ \pi^-$, $\Lambda_b^0 \to \Lambda \phi$ and $B_s^0 \to K_{\rm S}^0 K^*$ are observed for the first time by LHCb and their branching fractions are measured. Evidence is seen for the $\Lambda_b^0 \to \Lambda \pi^+ \pi^-$ decay and limits are set for the decays $\Xi_b^0\to \Lambda h^+ h^{(\prime)-}$ and $B^0 \to K_{\rm S}^0 K^*$ . The phase-space integrated CP asymmetry parameters are measured for $\Lambda_b^0 \to \Lambda K^+ K^-$ and $\Lambda_b^0 \to \Lambda K^+ \pi^-$ while several triple-product asymmetries are measured for $\Lambda_b^0 \to \Lambda \phi$. All these asymmetries are found to be compatible with zero.