HyperIso: A general BSM calculator for flavour observables

We present HyperIso, a new standalone program for the evaluation of flavour physics observables across a wide variety of Standard Model (SM) and Beyond-the-Standard-Model (BSM) scenarios. The code builds on the physics heritage of SuperIso, but is implemented as a new modular software package with a modern C++ core and multiple user interfaces. In addition to native implementations for established scenarios such as the SM, the general Two-Higgs-Doublet Model (THDM), and supersymmetric models, HyperIso interfaces with the MARTY framework to compute automatically BSM Wilson coefficients at leading order. This design makes it possible to study user-defined BSM models while keeping the observable calculation, uncertainty propagation and statistical interpretation in a common backend. The software provides C++, Python, command-line and graphical interfaces. It supports the evaluation of key observables such as the branching ratios and, where available, angular observables, for radiative, leptonic, and semileptonic B decays, as well as for the relevant kaon and D-meson decays, together with the muon anomalous magnetic moment (g-2). The inputs can be provided through JSON/YAML configuration files and Les Houches Accord files, either supplied by the user or generated by external spectrum calculators. HyperIso therefore provides a flexible and extensible tool for flavour studies, phenomenological scans and the validation of BSM scenarios.