LHCb RICH Online-Monitor and Data-Quality

The LHCb experiment at the LHC (CERN) has been optimised for high precision measurements of the beauty quark sector. Its main objective is to precisely determine and over-constrain the parameters of the CKM mixing matrix, and to search for further sources of CP violation and new physics beyond the Standard Model in rare B-decays. Efficient particle identification at high purities over a wide momentum range from around 1 to ~100GeV/c is vital to many LHCb analyses. Central to the LHCb particle identification strategy are two Ring Imaging CHerenkov (RICH) detectors which use Silica Aerogel and C4F10 and CF4 gas radiators. A rigorous quality control scheme is being developed to insure that the data recorded by the RICH detector meets the stringent requirements of the physics analyses. The talk summarises the LHCb RICH online monitoring and data-quality strategy. Multiple dedicated algorithms are deployed to detect any potential issue already during data-taking ranging from integrity checks, mis-alignments to changes in the refractive determined from changes in the radii of Cherenkov rings found using a Markov Chain approach. A further key ingredient is the online monitoring of the particle ID performance using multiple exclusively reconstructed decay channels where the particle identity can be determined from kinematic constraints. In addition, any re-calibration of the detector can be performed using a dedicated express stream covering a dedicated data-taking period. The same tests are performed during the reconstruction phase of the full statistics of the recorded data to verify the quality of the data before made available for physics analyses.