Charmless b-hadron decays at LHCb

Abstract

Violation of charge-parity ($C\!P$) symmetry in the Standard Model is driven by a single global phase, however manifestations of $C\!P$ violating quantities are often non-trivial due to the role of the strong interaction in generating observable $C\!P$ violation effects. Here we explore how the role of the strong phase in $B^+ \rightarrow \pi^+\pi^+\pi^-$ decays, described by the intermediate resonance structure and final-state rescattering effects, governs the manifestation of large $C\!P$ violation. Significant $C\!P$ violation is observed in the scalar and tensor contributions, along with the first observation of $C\!P$ violation in the interference between two competing decay amplitudes. Additionally $P$ and $C\!P$ violation are tested for in the phase-space of $\Lambda_b^0 \rightarrow p^+\pi^-\pi^+\pi^-$ decays using model-independent triple-product asymmetry and energy-test methods, with a first observation of $P$ violation in $b$-baryon decays.