Experimental e + e - physics – LEP&LC

RECFA RECFA September September 26 200326 2003 RECFA RECFA September September 26 200326 2003

Kenneth Österberg, University of Kenneth Österberg, University of HelsinkiHelsinki


Experimental e+e- physics – LEP&LC

Experimental e+e- physics – LEP&LC

DELPHI

Major finnishLEP contribution

analysis contribution

1994-99

OPAL

L3

ALEPH

Kenneth Österberg, lecturer at High Energy Physics Division, Department of Physical Sciences &

project leader at Helsinki Institute of Physics, University of Helsinki




Barrel Hadron Calorimeter

Forward Hadron Calorimeter

Vertex Detector

Finnish DELPHI contributions (1983-)

Finnish DELPHI contributions (1983-)

& Physics analysis& Physics analysis




DELPHI Vertex Detector (1990-1995)DELPHI Vertex Detector (1990-1995)• 1990: Two layers of single-sided sensors 1990: Two layers of single-sided sensors

• Mechanical support structure and readoutMechanical support structure and readout

• 1991: A third single-sided layer added (& beam pipe radius reduced)1991: A third single-sided layer added (& beam pipe radius reduced)

• Finnish VTT sensors used, mechanical support structure & mountingFinnish VTT sensors used, mechanical support structure & mounting

• 1994: Two layers exchanged to double-sided double-metal sensors1994: Two layers exchanged to double-sided double-metal sensors

• Double-sided double-metal sensor development, mounting & coolingDouble-sided double-metal sensor development, mounting & cooling

• Design & feasibility studies; development of the reconstruction software Design & feasibility studies; development of the reconstruction software

Jig setup for outer layer Jig setup for outer layer module assembly in the module assembly in the Helsinki detector labHelsinki detector lab




• Three extended double-sided layers & forward pixels+ministrips crownsThree extended double-sided layers & forward pixels+ministrips crowns

• Outer layer module assembly in Helsinki and mounting at CERNOuter layer module assembly in Helsinki and mounting at CERN

• Software development work & coordinationSoftware development work & coordination

• Running responsibility & full project coordination 1999-2001Running responsibility & full project coordination 1999-2001

DELPHI Silicon Tracker (1996-2000)DELPHI Silicon Tracker (1996-2000)




Physics analysis LEP1Physics analysis LEP1• SearchesSearches: : New particles in events with New particles in events with ’s (L3), lepton flavour ’s (L3), lepton flavour violation, heavy violation, heavy ’s, squarks and charged Higgses.’s, squarks and charged Higgses.

• B- and B- and -physics-physics: : b b ul ul decays, exclusive charmless B meson decays, exclusive charmless B meson decays, inclusive charmless and double-charm b decays, moments decays, inclusive charmless and double-charm b decays, moments of the lepton spectrum in semileptonic b decays, charged K’s in of the lepton spectrum in semileptonic b decays, charged K’s in decays, Bdecays, B00

ss and and bb mass and search for b mass and search for b s s and b and b s s decays. decays.

• Final state interactionsFinal state interactions: : colour portraits in bbg events, dead cone colour portraits in bbg events, dead cone effect in heavy flavour decays, interference of neutral kaons and effect in heavy flavour decays, interference of neutral kaons and production of quarkonia in hadronic Zproduction of quarkonia in hadronic Z00 decays. decays.

signal of b signal of b ul ul transitions transitions the LEP the LEP combined result gives combined result gives ~15 % precision on |V~15 % precision on |Vubub|.|.

DELPHI




Physics analysis LEP2Physics analysis LEP2

• SearchesSearches: : Charged and Charged and neutral Higgses.neutral Higgses.

• QCDQCD: : Colour coherence Colour coherence phenomena phenomena (colour portraits (colour portraits & interconnection effects).& interconnection effects).

• ElectroweakElectroweak: : Hadronic Hadronic cross section (L3).cross section (L3).

DELPHI preliminary

Limit assuming no H W*A decay

BR

(H+

)

MH(GeV/c2)

Final DELPHI result on the search Final DELPHI result on the search for the charged Higgs that is just to for the charged Higgs that is just to be published !! (finnish analysis of be published !! (finnish analysis of the fully hadronic decay channel)the fully hadronic decay channel)




Current activitiesCurrent activitiesMeasurement 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

for more details see M. Battaglia et al. (with L. Salmi), hep-ph/0210319

1 (

GeV

2 /c4 )

mb (GeV/c2)




Some unofficial statistics Some unofficial statistics

ThesesTheses (including both analysis and detector related):

• 12 PhD’s (+ 2 more to be finalized by summer 2004)12 PhD’s (+ 2 more to be finalized by summer 2004)

• ~ 25 MSc and Lic. Phil.~ 25 MSc and Lic. Phil.

PublicationsPublications:

• ~ 300 DELPHI physics papers in refereed journals with ~ 300 DELPHI physics papers in refereed journals with 1010 finnish authors (L3: ~ 150 papers and finnish authors (L3: ~ 150 papers and 22 authors) authors)

• ~ 25 of those with Finn(s) as main/one of the main contributors~ 25 of those with Finn(s) as main/one of the main contributors

• ~ 35 papers in refereed journals on detectors or experimental ~ 35 papers in refereed journals on detectors or experimental methods by finnish authorsmethods by finnish authors

• 50 internal notes by finnish authors50 internal notes by finnish authors

Disclaimer: numbers should be taken as approximative, not as absolute & factual numbers !!Disclaimer: numbers should be taken as approximative, not as absolute & factual numbers !!




Linear collider (LC)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

Measurement precision of Higgs Br’s, width & potential + charged Higgs mass reconstruction

Conceptual design of a Vertex Tracker

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




Conclusions & reflectionsConclusions & reflections

• 11stst finnish involvement in a large scale HEP experiment that included finnish involvement in a large scale HEP experiment that included all aspects (design & feasibility work, hardware, software & analysis) !!all aspects (design & feasibility work, hardware, software & analysis) !!

• Finnish LEP/DELPHI effort was successful ... Finnish LEP/DELPHI effort was successful ... however activity is winding down however activity is winding down (to be completed by the end of (to be completed by the end of 2004).2004).

• Knowledge and experience have been acquired and already have Knowledge and experience have been acquired and already have been applied to feasibility studies for future LC been applied to feasibility studies for future LC establish a small scale project focused on finnish establish a small scale project focused on finnish detector R&D and finnish physics feasibility studies for future LC !! detector R&D and finnish physics feasibility studies for future LC !!

• Students need more supervision Students need more supervision (modern HEP experiments are complex)(modern HEP experiments are complex) increase number of supervisors increase number of supervisors (establish a few new finnish post-doc type (establish a few new finnish post-doc type positions in experimental HEP that should be both attractive & longer term)positions in experimental HEP that should be both attractive & longer term) !! !!

Experimental e + e - physics – LEP&LC

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