Search for Flavour Changing Neutral Currents through Single Top-Quark Production at √s= 8 TeV with the ATLAS Detector
Search for Flavour Changing Neutral Currents through Single Top-Quark Production at √s= 8 TeV with the ATLAS Detector
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DissertationPrüfungsdatum
20.07.2017Datum der Veröffentlichung
20.12.2017Erstgutachter
Brock, Ian C.Zweitgutachter
Dingfelder, Jochen ChristianMetadaten
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Inhalt
Flavour changing neutral current processes are highly suppressed in the Standard Model due to the Glashow-Iliopoulos-Maiani mechanism. However, many extensions of the Standard Model predict the existence of these processes with higher branching fractions, where some are within the reach of the current particle accelerators. In this thesis, an experimental search for flavour changing neutral currents during single top-quark production in proton–proton collisions at the LHC is presented. The main search process involves the interaction of an up- or charm–quark with a gluon, producing a single top quark, which then decays into a W boson and a b quark. The W boson then decays leptonically. The data collected by the ATLAS detector during 2012 from the 8 TeV centre-of-mass energy collisions, corresponding to an integrated luminosity of 20.3 fb-1 are used. The signal- and background-like events are classifed using neural networks. As no sign of signal is observed, an upper limit on the production cross-section multiplied by the t → Wb branching fraction is set. The observed 95 % CL limit is σqg→ t × B (t → Wb)<2.9 pb. The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics κugt/Λ < 5.8×10-3 TeV-1 and κcgt/Λ < 13 ×10-3 TeV-1 and on the branching fractions B(t → ug) <4.0×10-5 and B(t → cg) <20×10-5.
Klassifikation (DDC)
530 PhysikArslan, Ozan: Search for Flavour Changing Neutral Currents through Single Top-Quark Production at √s= 8 TeV with the ATLAS Detector. - Bonn, 2017. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-49214
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-49214
@phdthesis{handle:20.500.11811/7311,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-49214,
author = {{Ozan Arslan}},
title = {Search for Flavour Changing Neutral Currents through Single Top-Quark Production at √s= 8 TeV with the ATLAS Detector},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2017,
month = dec,
note = {Flavour changing neutral current processes are highly suppressed in the Standard Model due to the Glashow-Iliopoulos-Maiani mechanism. However, many extensions of the Standard Model predict the existence of these processes with higher branching fractions, where some are within the reach of the current particle accelerators. In this thesis, an experimental search for flavour changing neutral currents during single top-quark production in proton–proton collisions at the LHC is presented. The main search process involves the interaction of an up- or charm–quark with a gluon, producing a single top quark, which then decays into a W boson and a b quark. The W boson then decays leptonically. The data collected by the ATLAS detector during 2012 from the 8 TeV centre-of-mass energy collisions, corresponding to an integrated luminosity of 20.3 fb-1 are used. The signal- and background-like events are classifed using neural networks. As no sign of signal is observed, an upper limit on the production cross-section multiplied by the t → Wb branching fraction is set. The observed 95 % CL limit is σqg→ t × B (t → Wb)<2.9 pb. The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics κugt/Λ < 5.8×10-3 TeV-1 and κcgt/Λ < 13 ×10-3 TeV-1 and on the branching fractions B(t → ug) <4.0×10-5 and B(t → cg) <20×10-5.},
url = {https://hdl.handle.net/20.500.11811/7311}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-49214,
author = {{Ozan Arslan}},
title = {Search for Flavour Changing Neutral Currents through Single Top-Quark Production at √s= 8 TeV with the ATLAS Detector},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2017,
month = dec,
note = {Flavour changing neutral current processes are highly suppressed in the Standard Model due to the Glashow-Iliopoulos-Maiani mechanism. However, many extensions of the Standard Model predict the existence of these processes with higher branching fractions, where some are within the reach of the current particle accelerators. In this thesis, an experimental search for flavour changing neutral currents during single top-quark production in proton–proton collisions at the LHC is presented. The main search process involves the interaction of an up- or charm–quark with a gluon, producing a single top quark, which then decays into a W boson and a b quark. The W boson then decays leptonically. The data collected by the ATLAS detector during 2012 from the 8 TeV centre-of-mass energy collisions, corresponding to an integrated luminosity of 20.3 fb-1 are used. The signal- and background-like events are classifed using neural networks. As no sign of signal is observed, an upper limit on the production cross-section multiplied by the t → Wb branching fraction is set. The observed 95 % CL limit is σqg→ t × B (t → Wb)<2.9 pb. The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics κugt/Λ < 5.8×10-3 TeV-1 and κcgt/Λ < 13 ×10-3 TeV-1 and on the branching fractions B(t → ug) <4.0×10-5 and B(t → cg) <20×10-5.},
url = {https://hdl.handle.net/20.500.11811/7311}
}
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