Analysis of Long Lived Particles with BuSca at LHCb.

BuSca stands for Buffer Scanner and is a LHCb project prototype designed for long-lived particle searches in real-time, leveraging the enhanced parallelization capabilities of the new LHCb trigger scheme implemented on GPUs (the Allen project). BuSca algorithms are focused at present on downstream reconstructed tracks, which exclusively let hits in the UT and SciFi detectors. By projecting physics candidates onto 2D histograms of flight distance and mass hypotheses at 30 MHz rate, BuSca identifies hot spots indicative of potential candidates of new particles, thereby providing strategic guidance for the development of new trigger lines. Additionally, BuSca offers an A<rmenteros-Podolanski representation, providing insights into the mass hypotheses of the decay products associated with the new particle. The design and performance of BuSca, including the outcomes of its initial prototype on simulated and real data, are presented in this manuscript.