Measurement Of CP Violation In Angular Distribution Of ∧_c~+→∧K~+ Decay In LHCb

CP violation in the quark sector is one of the major research areas of particle physics.Since the discovery of CP symmetry breaking in neutral K decays in 1964,CP violation effects have also been observed in the B system,which axe all found to be consistent with the CKM mechanism.However,the CP violation in charm sector has not been explored yet.CP violation effect with charm hadrons is predicted to be tiny in the Standard Model,and no such effect has been established experimentally so far.The large amount of ∧c+ baryons that have been and will continue to be collected at the LHCb experiment can provide a great opportunity for study of CP violation.In this analysis,CP violation in angular distribution of ∧c+→∧K+ and ∧c-→∧K-decays are measured for the first time,using 1.67fb-1 of data collected by LHCb at a center-of-mass energy of(?)= 13 TeV in proton-proton collisions.The decay asymmetries α∧c+ and α∧c-are estimated from the distributions helicity angles for proton and antiproton respectively,which are used to obtain the average decay asymmetry parameter α∧c=-0.576±0.037 and CP violation ACP=-0.010±0.040.The systematic uncertainties of this preliminary result need further study and can be significantly improved.The measurement uncertainties have significant contributions from the limited sizes of the Monte Carlo data samples used to understand detector effects.It is very important to develop new techniques for fast generation of large MC samples,using which we can further improve the analysis method and estimation of systematic un-certainties,and eventually achieve precise measurements of the asymmetry parameter and CP violation in the decay ∧c+→∧K+.