A precise measurement of the Lambda_b production asymmetry is critical to the measurements of CP violation in the decay of b-baryons at LHCb. In general these production asymmetries cannot be precisely predicted since they require knowledge of non perturbative b-quark hadronisation processes, and so need to be experimentally determined. The semileptonic Lambda_b->Lambda_c mu nu decay offers an excellent tool for precise measurement of such production asymmetry. It has a large branching fraction and a clear experimental signature with the presence of a high transverse momentum muon. Furthermore, it is theoretically clean and the CP violation in the decay can be safely assumed to be negligible. The first observation of the Lb-anti-Lb baryon production asymmetry is presented, together with strong evidence of a dependence of this production asymmetry with the rapidity.
|First author||Stefania Ricciardi|
|Collaboration / Activity||LHCb|