1. DELPHI involvement of the Institute for High Energy Physics of the Austrian Academy of Sciences DELPHI L3 OPAL ALEPH

2. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Overview u One of two Austrian participations in the LEP programme (see also next talk on ALEPH) u The only Austrian institute in DELPHI (out of ~56) - member since the design phase u Typically 10 out of ~ 550 authors on DELPHI papers u Contributions to DELPHI construction and running budgets at the level of about 2% u External funding from â Phase 1: Austrian Science Fund (FWF) â Phase 2 (LEP II upgrade): Austrian Ministry of Eduction, Science and Culture u Construction of detectors and electronics in collaboration with Austrian industry

3. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Hardware - Contributions Forward Chamber A Silicon Tracker

4. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 u FCA: Part of the forward tracking system â Two arms with six layers of streamer tubes each â Provided track trigger in the forward region and â 4D track segments for reconstruction (together with a 2 nd set of drift chambers and the DELPHI TPC) u Designed, constructed and operated by HEPHY for the DELPHI data-taking 1989 - 2000 Forward Chamber A Mounting of one FCA module on the TPC endplate

5. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Readout and Trigger Electronics DELPHI electronics in the FASTBUS standard: u Multiplexing for parts of the forward chamber readout u Design, construction and operation of the forward track trigger at level 1 & 2: â Linking hits in FCA and FCB with momentum selection and check for compatibility with interaction point u Maintenance of the standard time digitizer “LTD” for the whole collaboration FASTBUS multiplexer for drift chamber signals

6. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 u The forward part of the extended Silicon Tracker installed in the framework of the upgrade programme for LEP II : â two crowns of pixel and two crowns of “mini-strip” detectors in each endcap u Leading participation of Austria in the mini-strip system â development of a simple and robust system with resolutions matched to the effects of multiple scattering in the very forward region  single-sided detectors with 200  m pitch â glued back-to-back to provide intersection points in 2D u Operated by the Silicon Tracker group throughout LEP II data-taking (1996-2000) Very Forward Tracker Forward region of a halfshell of the Silicon Tracker Two crowns of mini-strips

7. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Pattern Recognition & Track Fitting Contributions to track reconstruction in DELPHI u Introduction of the Kalman Filter â Proof of the equivalence of previously developed iterative track fitting algorithms with the Kalman filter (widely used outside HEP) â Use of the full advantage of the Kalman approach: flexibility and optimal estimates everywhere on the track by combining a filtering and smoothing stage u Development of an electron track fit â Treatment of radiative energy loss in a least-squares track fit u Local pattern recognition in FCA â resolution of ambiguities using a Hopfield-network

8. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 u Application of the Kalman filter to vertex reconstruction â equivalent to least-squares fit â iterative procedure, suitable for attaching / detaching tracks to / from a vertex u Robustified vertex fits  Kalman filter with  2 tests of individual tracks â Vertex fits based on the M-estimator algorithm u Application of these procedures to â primary vertex reconstruction â secondary vertex reconstruction in c- and b-events Vertex Fitting

9. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Physics Analyses LEP I u B-Physics: â Early analysis of B-lifetime â Exclusive reconstruction of rare B-decays, e.g. search for charmless decays of B-hadrons â Exclusive decays of B-hadrons to J/  X â Inclusive b decays to wrong sign charmed mesons u Tau-production â cross-section and asymmetry measurement Here & following pages: Analyses done by or with strong participation of HEPHY physicists reconstruction of displaced vertices

10. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Physics Analyses QCD u Multiparticle correlations in Z 0 decays â Angular correlations and correlation integral studies u 3-jet events at  s = M Z â comparison of the leading systems in gluon- and quark-jets u Identified hadron spectra at LEP II â Pion, kaon and proton spectra in e + e -  qq and hadronic W-decays â Using dE/dx (TPC) and Cherenkov angles (RICH) â Motivated by the temporary involvement of several Austrian physicists in the DELPHI RICH project maximum of -log(2p/√s) vs.  s

11. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Physics Analyses Searches u Search for a scalar top quark â Analysis of the decay mode to b lepton sneutrino in the first part of LEP II u Contributions to other searches at LEP II â Higgs â Excited leptons â Technicolor Excluded regions in the techni-pion vs. techni-rho mass plane

12. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Co-ordination u Co-ordination & general tasks of HEPHY members : â Resonsibility for sub-detector operations and in global data-taking â Mandate in the DELPHI executive committee â Co-ordination of LEP II analyses, responsible for topologies with leptons or E miss / searches for Exotica â Co-ordination of the LEP working group for searches for Exotica u Activity now on the follow-up of the remaining publications

13. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Outreach u Activities in Austria â Since the end of DELPHI data-taking detector parts have been prepared for presentation to the public. â They form a key element of an exhibition shown at museums, high schools and universities. u DELPHI exhibition at CERN â A specially prepared module of the forward chamber will be shown in its original position on the DELPHI barrel in the context of the permanent exhibition in the former DELPHI / now LHCB pit. FCA on display

14. W.Adam: DELPHIRECFA. Innsbruck, 26/03/04 Summary u Some statistics (approximate numbers!) â typically 10 HEPHY authors on ~ 350 DELPHI publications â ~ 70 DELPHI notes (co-) authored by HEPHY physicists â + DELPHI-related publications on detector development and reconstruction algorithms â ~ 14 diploma theses and 6 PHDs u Conclusion â The participation in DELPHI was an important step in the experimental programme of the institute. â There were significant Austrian contributions to hardware, software and analysis. â The know-how gained in this way is now used for the next generation of experiments with HEPHY-involvement.