Medusa, a multithread 4-body decay fitting and simulation software

We present a new C++14 compliant application to perform physics data analyses of generic 4-body decays in massively parallel platforms. Medusa is highly based on Hydra, a header-only library which hides most of the complexities of writing parallel code for different architectures. Medusa has been tested through the measurement of the CP-violating phase ϕsin b-hadron decays exploiting the data collected by the LHCb experiment. Medusa executes the optimization of the full model, running over 500000 events, until 330 times faster than a non-parallelized program. Medusa is freely available on GitHub under GPL v.3.0 license.