Real-time physics, alignment and reconstruction in the LHCb trigger
2018 September 24
Since 2015, the LHCb experiment has employed an exclusively-real-time analysis strategy for a large fraction of its physics programme. Full physics analyses are performed directly on the objects reconstructed in the final stage of the software trigger, negating the need for subsequent offline reconstruction and reducing the output event size, without a loss of performance. In mid-2017, an extension of the associated persistency model was made to allow a completely flexible set of physics objects to be saved for subsequent study, greatly increasing the potential for speculative analysis and data mining. This model and its recent extension are motivated and described, as are the real-time alignment and calibration techniques that permit the strategy to provide offline-equivalent performance.