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Integrated Tracker – STAR tracking framework of the future

Integrated Tracker – STAR tracking framework of the future. update on status and perspective IT(TF) efforts. Present status of Integrated Tracker (aka ITTF, Sti or simply IT).

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Integrated Tracker – STAR tracking framework of the future

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  1. Integrated Tracker – STAR tracking framework of the future update on status and perspective IT(TF) efforts Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  2. Present status of Integrated Tracker (aka ITTF, Sti or simply IT) • By May 2005 in general a wave of bug fixes and ITTF codes clean ups started in fall of 2004 (V.Perevoztchikov et al.) has been finished . • After evaluation and verification in June 2005 ITTF has been used for pp-production of 2005 data (no SVT). • More modifications were made during last 6 months to provide more stable fitting, but • main efforts were concentrated around SVT. Spiros has already presented conclusions: • SVT is too far from TPC. This creates high level ghosting in high hit density environment, • SVT does not meet specification (we believe that this is due to misalignment) • But there is a hope that with SSD and with SVT+SSD self alignment the situation can be improved. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  3. Present status (cont.) • IdTruth information has been added for SVT and SSD. This makes big impact on quality of ITTF verification. Presence of the IdTruth information is vital for any new detector development and evaluation. • Track reconstruction with both SVT and SSD (thanks SSD team and especially Lilian Martin) for both simulation and data is available now in ITTF. • Adding any new “barrel’’ type detector is straight forward (it just require to use STAR data model --- StEvent --- to feed ITTF). Thus HFT and IST,IGT can be used in ITTF practically as soon as their hits will be in StEvent. Adding forward detectors (FTPC, FST, FGT,..) still requires some work. • Last month ITTF performance (for TPC only data) has been reevaluated with respect to TPT. No problems have been found. Results of the track by track comparison between ITTF and TPT chains presented in the next slides. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  4. Efficiencies ITTF(Sti) versus TPT(TPC only) AuAu200 ITTF is slightly better than TPT CuCu62 pp200 Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  5. pT Differences (TPC only) 20 MeV/c AuAu200 CuCu62 pp200 Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  6. Relative pT differences (TPC only) AuAu200 Deviations are within a few ‰ CuCu62 pp200 Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  7. Momentum resolution of primary tracks (simulation). • The only new problem found so far is primary tracks momentum resolution: • Global tracks resolutions (Gl) for both ITTF and TPT are practically the same • Resolution of primary tracks (Pr) in ITTF is worse than in TPT. Addition of primary vertex practically does not improve resolution as we expected. • This is due to fact that ITTF does not require convergence of primary track fit. • The track refit procedure has been rewritten by Victor and is now under test. We expect that this procedure will take care about the convergence issue. TPT: Adding primary vertex improves resolution by a factor of ~2 (from 2.6% to 1.4% at 2GeV/c) ITTF: Improvement only by ~20% Primary track fit has not converged Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  8. Status (cont.) • Except the above problem with convergence for primary track fit, which has been addressed and will be fixed in time scale of a few days, we can state that the ITTF performance for TPC only is the same or better than TPT. • SVT has been covered by Spiros • ITTF has and will have more features (SSD, new detectors,…) which do not exist in TPT i.e. ITTF is the Integrated Tracker (still for barrel like detectors only but we have plan to address this issue too). • Thus we can state that: • We are ready to do physics evaluation of ITTF with respect to TPT; • After successful ITTF evaluation • we can declare ITTF as baseline tracker for existing detector, and • ITTF is (almost) ready for R&D with new detectors. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  9. Perspective IT(TF) efforts ITTF still requires dedicated efforts for clean ups and improvements. The plan to improve ITTF includes 3 items: • To use VMC geometry • To expand ITTF with more (multiple) user friendly Plug-ins • To add missing parts: smoother and vertex fitter. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  10. VMC Geometry • The main limitation in ITTF is the geometry model. It is essentially 2D+1 geometry which is suited for ``barrel’’ like detectors but it has problem with including forward detectors (FTPC,...). • VMC Geometry: • Allows to use all (GEANT) knowledge of the whole detector, including dead materials,… • Track parameter propagation in VMC will solve problem with including forward detectors. It has been shown that usage VMC propagation should not degrade performance of ITTF. • Account for non uniform magnetic field, propagation outside of STAR TPC volume • Track extrapolation outside of track detector regions to provide prediction in ToF, Calorimeters,… • Main step in this direction is to provide simulation with VMC in STAR framework. This step has been completed. STAR VMC simulation is ready for evaluation right now. • Next step is to provide ITTF with VMC based propagator(s). Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  11. More Plug-ins • There is an architectural problem with Plug-ins in ITTF. There is plug-in mechanism in StMaker-scheme (based on data transfer via TDataSet) and plug-in mechanism in ITTF itself. We have to make an architecture choice. • Expanding ITTF with (multiple) user friendly Plug-ins • Multiple track parameter propagators (precise, fast, Runge Kutt, VMC,..) • Multiple (alternative) track seeders (there is a request from EMC group for reconstruction beam halo tracks). • This work has been started. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  12. Adding missing parts • Smoother • Adding smother allows (besides fit stability, outlier removal, …) also to control our alignment parameters. We expect the smoother will be in the next ITTF release. • Vertex fitter • We have multiple primary vertex fitters outside of ITTF. Idea is to use whole track information including track parameters covariance matrix available in ITTF to fit multiple vertices. • … Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

  13. Conclusion • We have the stable Integrated Tracker (ITTF) which is factually ``baseline’’ STAR tracker. • ITTF can serve the present needs of the STAR and most of requests for R&D tracking detectors. • The Star Integrated Tracker has potential to be improved. • Any new (R&D) detector has to use ITTF. Any efforts to by pass official ITTF is wasting time and resources. Y.Fisyak, BNL - STAR Upgrade workshop, 12/2/2005

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