New software technologies in the LHCb Simulation

Monte Carlo simulations are key to the design and commissioning of new detectors as well as the interpretation of physics measurements. The amount of simulated samples required for the Run 3 physics program of the LHCb experiment will increase significantly from 2022 onward to match the increase in the amount of data collected with respect to Run 1 and 2 operation. A new version of the LHCb Gauss simulation framework has been developed to better accommodate new simulation techniques and software technologies to produce the necessary samples within the computing resources allocated for the next few years. It provides the LHCb specific functionality while the generic simulation infrastructure has been encapsulated in an experiment-independent framework, Gaussino. The latter combines the Gaudi core software framework and the Geant4 simulation toolkit and fully exploits their multi-threading capabilities. Fast simulation interface is the latest feature being developed in Gaussino to interact with Geant4 giving the possibility of replacing its detailed description of physics processes with an extensive palette of fast simulation models for a specific LHCb sub-detector. A facility to ease the production of training datasets for fast simulations models has also been introduced.