Search for $CP$ violation in $\Lambda_b^0 \to pK^-$ and $\Lambda_b^0 \to p \pi^-$ decays at LHCb

The LHCb experiment at the Large Hadron Collider has been designed to perform high-precision flavour-physics measurements. In particular, $CP$-violation measurements are of great importance to shed light on some open issues related to the baryon asymmetry in the Universe and to find evidence for physics beyond the Standard Model. A search for $CP$ violation in $\Lambda_b^0 \to pK^-$ and $\Lambda_b^0 \to p \pi^-$ decays using an integrated luminosity of 3.0 fb$^{-1}$ collected by the LHCb experiment during Run 1 is presented. The $CP$ asymmetries are found to be $A_{CP} (pK^-)$ = −0.020 ± 0.013 ± 0.019 and $A_{CP} (p\pi^-)$ = −0.035 ± 0.017 ± 0.020, where the first uncertainties are statistical and the second systematic. No evidence for $CP$ violation is found.