BESIII Offline Software Overview Weidong Li & Yajun Mao BESIII Collaboration Meeting, Beijing 12 January 2006

12/01/2006W.Li and Y. Mao2 Infrastructure and Environment  Underlying framework GAUDI (originally developed by LHCb)  Simulation GEANT4  Other external LIBs: CERNLIB, CLHEP, ROOT, AIDA, XercesC, GDML …  Database: PGSQL/MySQL  Software configuration management CMT and CVS  Computer language: C++ (BESII legacy code written in Fortran )  Operation system: Redhat 7.3/gcc3.2  Reused code from Belle, BaBar, ATLAS,GLAST …

12/01/2006W.Li and Y. Mao3 Organization   Institutes participating Institute of High Energy Physics Peking University Shandong University University of Science and Technology of China Hunan University Zhejiang University Joint Institute for Nuclear Research, Russian Kanglin He Huaimin Liu Zepu Mao Jinfa Qiu Weidong Li

12/01/2006W.Li and Y. Mao4 Event Data  HEPEVT Data Kinematics information only  RAW Data Delivered by DAQ for reconstruction Byte stream format  Simulated Event Data Contain digits, hits and other MC truth information Ascii file format  REC & DST Data Reconstructed Data is event data written as output of reconstruction procedure DST Data is a reduced event representation suitable for analysis Both in ROOT format RAW Data Simulated Event Data Event Data Generator HEPEVT Data Data G4 Simulation Reconstruction Rec & DST Data Data

12/01/2006W.Li and Y. Mao5 Event Data Conversion Services Algorithm A Algorithm B Algorithm C Data T1 Data T2, T3 Data T2 Data T3, T4 Data T4 Data T5 T1 T5 Real data flow Apparent data flow T2 T4 T3

12/01/2006W.Li and Y. Mao6 Detector Description  Based GDML (Geometry Description Markup Language), a kind of XML developed by GEANT4 group.  Peking University group expanded the GEANT4 Schema and developed a new ROOT Schema for BESIII applications.  GDML Detector Description has been used for simulation, event display and MUC reconstruction. Classes for Simulation Geometry, Materials, Alignment… XML description Classes for Reconstruction Classes for Event Display ROOT Schema XML writer GEANT4 Schema

12/01/2006W.Li and Y. Mao7 Access to Geometry Data TOF GeomSvc EMC GeomSvc MUC GeomSvc MDC GeomSvc ApplicationLayer TOF DAO EMC DAO MUC DAO MDC DAO Database Geometry, Materials XML description Objects for Reconstruction Data Access Layer

12/01/2006W.Li and Y. Mao8 Event Display Tool: BesVis  Based on ROOT, OpenGL, X3D and XML  Support both 2D and 3D view  Operations and controls available through menu and toolbar items  First version was released in December 2005.

12/01/2006W.Li and Y. Mao9 Simulation Integration  BES has ~30 event generators written in Fortran  Use C++ Hepevt_Wrapper to access the kinematics information generated by the generators Transient Event Store Generator Simulation Simulation ② ①   BOOST (BESIII Objected Oriented Simulation Tool) was originally developed in a independent framework.   Integration with BOOST simulation is based on ATLAS/Athena software.   Currently both BES generators and BOOST have been integrated with the offline framework.

12/01/2006W.Li and Y. Mao10 Calibration Status  Framework is based on GLAST calibration infrastructure   Status Developed MDC, TOF and EMC calibration prototype algorithms Defined calibration data for each sub-detector Reconstruction algorithms are able to retrieved calibration constants through the framework. calibUtil interface Data (persistent)Metadata (persistent) Dead chns (XML) CAL calibs (ROOT) MySQL rdbms Write/register Search Read Signifies “uses” or “accesses”

12/01/2006W.Li and Y. Mao11 Drift Chamber Software Status  Simulation Stereo cells are described by G4TwistTube. Digitization is based on parameters from test beam data.  The calibration algorithm contains correction to X-T relation, spatial resolution,T0, wire position, time walk.  Reconstruction algorithms are: TrkReco and MdcPatRec. For single 1 GeV muons, both of them obtain: Efficiency: ~99% Spatial resolution: ~110 μm  dE/dx resolution: ~6% consistent with detector design report.

12/01/2006W.Li and Y. Mao12 TOF Software Status  Simulation Two-layered structure for Barrel Digitization takes into account: light production, light propagation and PMT response etc. Intrinsic time resolution: 85 ps  Calibration & reconstruction Calibration algorithm includes time correction, effective velocity and attenuation calibration. Reconstruction results have been used in particle identification

12/01/2006W.Li and Y. Mao13 EM Calorimeter Software Status  Simulation End-cap is described by G4IrregBox. Full simulation of readout electronics is included in digitization.  Energy calibration Digit calibration: converting ADC channels into energy. Cluster calibration: correcting non- linearity of readout signals.  Reconstruction ΔE/E = σ z = 0.6

12/01/2006W.Li and Y. Mao14 Muon Counter Software Status  Simulation RPC as sensitive detector Detailed to each read-out strip  Reconstruction Tracking algorithm is seeded by the tracks extrapolated from MDC. Searching for hits gap by gap within predefined windows.  Reconstruction efficiency: ~ 1GeV Ext track Fired strips Window

12/01/2006W.Li and Y. Mao15 Physics Analysis Software Status  Prototype software for physics analysis Analysis event data model Analysis event builder Kinematics fitting Secondary vertex finding Particle identification  Physicists already start checking physics performance.

12/01/2006W.Li and Y. Mao16 Online Event Selection Software  Fast reconstruction algorithms and steering prototypes that control event selection have been developed and tested in the online environment. Accept Reconstruction algorithms Consistent with criteria End of AlgSeq N N Y Reject Y Algorithm sequences StepSequencer Reconstruction result   Share the same framework with offline.   Fast reconstruction algorithms shall be executed step by step according to the predefined sequences. In each step, event is rejected if it does not satisfy any selection criteria.

12/01/2006W.Li and Y. Mao17 Release Status  BOSS alpha release integration with BOOST simulation ( done ) Running the reconstruction chain for MDC, TOF, EMC and MUC can be achieved in the BOSS Gaudi framework. ( done ) EDM for both Raw Data and reconstructed data developed. Completion of fully functional Event Data I/O. ( done ) Status: published on 30 th of May, 2005  BOSS beta release Simulation and reconstruction chain functions reasonably well and can successfully process thousands of events. ( done ) Common physics analysis tools and utilities available. ( done ) Physics study in BOSS can start. Status: published on 17 th of November, 2005

12/01/2006W.Li and Y. Mao18 Progress since 2005 Annual Meeting  Analysis software development Analysis event builder (done) Particle identification (done) Secondary vertex finding (done)  Calibration infrastructure and algorithm prototypes (done)  Event Display Tool: BesVis (done)  Migration to GDML detector description (done for MUC )  Performance studies (ongoing) Physics: efficiency and resolution System: algorithms’ benchmarking and profiling, memory leakage etc.  Cavern backgrounds and realistic detector simulation (ongoing)

12/01/2006W.Li and Y. Mao19 Areas where work is needed  Detector alignment, dead/hot channel services  Magnetic field service  Parameters database  Simulation of Level1 hardware trigger  Mixing of background events  Migration to Gaudi v16r4/LCGCMT_35 that has been tested in our target operation system (SLC3).  Analysis software will still evolve based on experience obtained from the current prototype.  Physics study for online Event Filter  Data Challenges

12/01/2006W.Li and Y. Mao20 Data Challenge (1)  Motivation To understand the BESIII computing environment CPU, storage and network requirements, system performances, bottle necks, etc… To check and validate the BESIII software  Iterate on a set of Data Challenges of increasing complexity Running ‘simulation’, ‘reconstruction’ and ‘analysis’ on a large scale Testing calibration procedures Adding trigger simulation and event filter algorithms Producing physics results

12/01/2006W.Li and Y. Mao21 Data Challenge (2)  It should include Subsystem tests: simulation, calibration, reconstruction and analysis Generation  simulation  digitization  background mixing  reconstruction  analysis Full offline chain test: Generation  simulation  digitization  background mixing  reconstruction  analysis Trigger/Event filter/Offline chain test Trigger/Event filter/Offline chain test Stress tests for scaled systems (10%, 25%…)

12/01/2006W.Li and Y. Mao22 Summary  A tremendous amount of progress in 2005 and people are focusing on more realistic digitization procedures. Simulation is in good shape and people are focusing on more realistic digitization procedures. Calibration Infrastructure and prototype algorithms have been developed. Reconstruction algorithms are being tuned for better performance. Physics analysis prototype software are also developed and are being used in physics studies.  Data challenge and software performance optimization are two major tasks this year.

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