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Experimental e + e - physics – LEP&LC

Experimental e + e - physics – LEP&LC. OPAL. ALEPH. Major finnish LEP contribution. L3. DELPHI. analysis contribution 1994-99.

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Experimental e + e - physics – LEP&LC

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  1. Experimental e+e- physics – LEP&LC OPAL ALEPH Major finnish LEP contribution L3 DELPHI analysis contribution 1994-99 Kenneth Österberg, lecturer at High Energy Physics Division, Department of Physical Sciences & project leader at Helsinki Institute of Physics, University of Helsinki Kenneth Österberg, University of Helsinki

  2. Finnish DELPHI contributions (1983-) Barrel Hadron Calorimeter Forward Hadron Calorimeter Vertex Detector & Physics analysis Kenneth Österberg, University of Helsinki

  3. Kenneth Österberg, University of Helsinki

  4. Kenneth Österberg, University of Helsinki

  5. DELPHI Vertex Detector (1990-1995) • 1990: Two layers of single-sided sensors • Mechanical support structure and readout • 1991: A third single-sided layer added (& beam pipe radius reduced) • Finnish VTT sensors used, mechanical support structure & mounting • 1994: Two layers exchanged to double-sided double-metal sensors • Double-sided double-metal sensor development, mounting & cooling • Design & feasibility studies; development of the reconstruction software Jig setup for outer layer module assembly in the Helsinki detector lab Kenneth Österberg, University of Helsinki

  6. DELPHI Silicon Tracker (1996-2000) • Three extended double-sided layers & forward pixels+ministrips crowns • Outer layer module assembly in Helsinki and mounting at CERN • Software development work & coordination • Running responsibility & full project coordination 1999-2001 Kenneth Österberg, University of Helsinki

  7. Physics analysis LEP1 • Searches: New particles in events with ’s (L3), lepton flavour violation, heavy ’s, squarks and charged Higgses. • B- and -physics: b  ul decays, exclusive charmless B meson decays, inclusive charmless and double-charm b decays, moments of the lepton spectrum in semileptonic b decays, charged K’s in  decays, B0s and b mass and search for b  s and b  s decays. • Final state interactions: colour portraits in bbg events, dead cone effect in heavy flavour decays, interference of neutral kaons and production of quarkonia in hadronic Z0 decays. DELPHI signal of b  ul transitions  the LEP combined result gives ~15 % precision on |Vub|. Kenneth Österberg, University of Helsinki

  8. Physics analysis LEP2 • Limit assuming no H  W*A decay • Searches: Charged and neutral Higgses. • QCD: Colour coherence phenomena (colour portraits & interconnection effects). • Electroweak: Hadronic cross section (L3). DELPHI preliminary BR(H+) Final DELPHI result on the search for the charged Higgs that is just to be published !! (finnish analysis of the fully hadronic decay channel) MH(GeV/c2) Kenneth Österberg, University of Helsinki

  9. Current activities Measurement of statistical moments of the leptonic energy spectrum in semileptonic B decays at LEP By measuring statistical moments of leptonic & hadronic B decay spectra, one can constrain the parameters of the model describing B hadrons  reduce the theoretical uncertainty related to the extraction of |Vcb| from experimental data. DELPHI preliminary 1 (GeV2/c4) for more details see M. Battaglia et al. (with L. Salmi), hep-ph/0210319   mb (GeV/c2) Kenneth Österberg, University of Helsinki

  10. Some unofficial statistics • Publications: • ~ 300 DELPHI physics papers in refereed journals with 10 finnish authors (L3: ~ 150 papers and 2 authors) • ~ 25 of those with Finn(s) as main/one of the main contributors • ~ 35 papers in refereed journals on detectors or experimental methods by finnish authors •  50 internal notes by finnish authors • Theses(including both analysis and detector related): • 12 PhD’s (+ 2 more to be finalized by summer 2004) • ~ 25 MSc and Lic. Phil. Disclaimer: numbers should be taken as approximative, not as absolute & factual numbers !! Kenneth Österberg, University of Helsinki

  11. Linear collider (LC) Extending knowledge & experience to a future LC Assume Higgs is found at LHC  studies at LC important to characterize the Higgs field Conceptual design of a Vertex Tracker Measurement precision of Higgs Br’s, width & potential + charged Higgs mass reconstruction Done within the framework of the 2nd ECFA/DESY study on physics & detectors for a e+e- LC  contributions to TESLA TDR Latest addition:  and AFB in top pair production at a few TeV LC that is very sensitive to tan Kenneth Österberg, University of Helsinki

  12. Conclusions & reflections • 1st finnish involvement in a large scale HEP experiment that included all aspects (design & feasibility work, hardware, software & analysis) !! • Finnish LEP/DELPHI effort was successful ... however activity is winding down (to be completed by the end of 2004). • Knowledge and experience have been acquired and already have been applied to feasibility studies for future LC  establish a small scale project focused on finnish detector R&D and finnish physics feasibility studies for future LC !! • Students need more supervision (modern HEP experiments are complex) increase number of supervisors (establish a few new finnish post-doc type positions in experimental HEP that should be both attractive & longer term) !! Kenneth Österberg, University of Helsinki

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