Search for the trilepton signal of the minimal supergravity model in DØ run II [Elektronische Ressource] / vorgelegt von Meta Binder

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Search for the Trilepton Signal of the MinimalSupergravity Model in DØ Run IID I S S E R T A T I O NderFakultät für PhysikderLudwig Maximilians Universität Münchenvorgelegt vonMeta Bindergeboren inSchäßburg, RumänienMünchen, den 24. Juni 2005Erstgutachterin: Prof. Dr. Dorothee SchaileZweitgutachter: Prof. Dr. Martin FaesslerTag der mündlichen Prüfung: 22.09.2005To my nieces and nephew:BirgitStefanieJohannes You arenever given a wishwithout also being given thepower to make it true.You mayhave to work for it,however.Richard BachccccncAbstractA search for associated chargino neutralino pair production is performed in the trilepton± 0 ± 0 ± ∓ 0e e e edecay channel qq¯→ → ‘ μ μ , using data collected with the DØ detector1 2 1 1at a center of mass energy of 1.96 TeV at the Fermilab Tevatron Collider. The data sample−1corresponds to an integrated luminosity of∼ 300 pb .A dedicated event selection is applied to all samples including the data sample andthe Monte Carlo simulated samples for the Standard Model background and the Super-symmetry signal. Events with two muons plus an additional isolated track, replacing therequirement of a third charged lepton in the event, are analyzed. Additionally, selectedevents must have a large amount of missing transverse energy due to the neutrino and the0etwo .1After all selection cuts are applied, 2 data events are found, with an expected numberof background events of 1.75± 0.34 (stat.)± 0.

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• Physik

Informations

• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2005
• Nombre de lectures: 3
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Search for the Trilepton Signal of the Minimal
Supergravity Model in DØ Run II
D I S S E R T A T I O N
der
Fakultät für Physik
der
Ludwig Maximilians Universität München
vorgelegt von
Meta Binder
geboren in
Schäßburg, Rumänien
München, den 24. Juni 2005Erstgutachterin: Prof. Dr. Dorothee Schaile
Zweitgutachter: Prof. Dr. Martin Faessler
Tag der mündlichen Prüfung: 22.09.2005To my nieces and nephew:
Birgit
Stefanie
Johannes You are
never given a wish
without also being given the
power to make it true.
You may
have to work for it,
however.
Richard BachAbstract
A search for associated chargino neutralino pair production is performed in the trilepton
± 0 ± 0 ± ∓ 0e e e edecay channel qq¯→ → ‘ μ μ , using data collected with the DØ detector1 2 1 1
at a center of mass energy of 1.96 TeV at the Fermilab Tevatron Collider. The data sample
−1corresponds to an integrated luminosity of∼ 300 pb .
A dedicated event selection is applied to all samples including the data sample and
the Monte Carlo simulated samples for the Standard Model background and the Super-
symmetry signal. Events with two muons plus an additional isolated track, replacing the
requirement of a third charged lepton in the event, are analyzed. Additionally, selected
events must have a large amount of missing transverse energy due to the neutrino and the
0
etwo .1
After all selection cuts are applied, 2 data events are found, with an expected number
of background events of 1.75± 0.34 (stat.)± 0.46 (syst.). No evidence for Supersymme
try is found and limits on the production cross section times leptonic branching fraction
are set.
When the presented analysis is considered in combination with three other decay
channels, no evidence for Supersymmetry is found. Limits on the production cross sec
tion times leptonic branching fraction are set. A lower chargino mass limit of 117 GeV
at 95% CL is then derived for the mSUGRA model in a region of parameter space with
enhanced leptonic branching fractions.
cccccn