Speaker
Description
The BESIII experiment has been operating since 2009, to study physics in the $\tau$-charm energy region utilizing the high luminosity BEPCII (Beijing Electron-Positron Collider II) double ring collider. The BESIII Offline Software System (BOSS) is built upon the Gaudi framework, while also leveraging ROOT extensively across its various components.
The BESIII experiment primarily utilizes ROOT for data management and storage. Most data, including simulated (rtraw), fully reconstructed (REC), and slimmed event data (DST), are stored in ROOT format, while RAW data remains in binary. The ROOT Conversion Service (RootCnvSvc), developed following Gaudi's specifications, enables bidirectional conversion between transient data objects (TDS) and persistent ROOT files. Calibration constants are serialized using ROOT and stored as BLOBs in databases, with functionalities for access provided by the BESIII Experiment Management Platform (BEMP). ROOT is also integral to validation workflows, where histogram-based comparisons serve as a critical benchmark for assessing both the functional accuracy and performance metrics of new software releases. Furthermore, the tag-based analysis software improves physics analysis efficiency by reorganizing DST events to boost the basket cache hit rate for non-contiguous data in ROOT. Many other tools, such as event display, also rely on ROOT.
