This repository contains the main software of the Belle II experiment.

It is used in all aspects of the data-processing chain, such as

• unpacking of real raw data,
• generating simulated data,
• reconstruction of particle decays (tracking, clustering, ...)

and high-level "analysis" reconstruction (such as applying selection criteria, vertex fitting, ...).

In addition to the code of this repository, the following three repositories are required:

• Belle II tools (public repository, internal repository): Scripts to install and set up basf2
• Belle II externals (public repository, internal repository): Manages external dependencies of basf2
• Belle II versioning (public repository, internal repository): Manages the different versions of basf2 and related conditions database global tags

Note that the history of the code is split in a part before (public repository, internal repository) and after (public repository, internal repository) July 7, 2021. Both parts are combined to a complete history with the b2code-history command.

Head to our documentation to learn about how to use basf2. If you are unsure about which version of the documentation to read, click on release-xx-xx-xx (recommended). We recommend you to start with the lessons of the Beginners' tutorials if you are just starting out.

More information about the core software can be found in the 2018 paper.