Measuring the Proton Detection Asymmetry at LHCb

Violation of charge-parity (CP) symmetry gives rise to a fundamental matter-antimatter asymmetry. However, this underlying distinction appears obscured in experiments, in part due to differences in the hadronisation process of quarks and antiquarks from proton-proton collisions leading to a production asymmetry, and due to the detection asymmetry resulting from differences in the nuclear interactions with detector material. Quantifying these effects is necessary to disentangle them from the fundamental CP asymmetry, and accordingly correct the measured raw asymmetry. Another strategy involves cancelling out the detection and production effects by taking the difference of the raw asymmetries of two decay modes [3, 6].