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Dissertations / Theses on the topic 'Single lepton'

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Published: 4 June 2021
Last updated: 15 February 2022

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1

Rehnisch, Laura. "Search for singly produced vector-like down-type quarks in single-lepton final states with ATLAS." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17493.

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In dieser Arbeit wird die Suche nach vektorartigen und angeregten Quarks mit einer elektrischen Ladung von Q = 1/3 mit dem ATLAS-Detektor vorgestellt. Die Existenz solcher Quarks wird von verschiedenen Modellen jenseits des Standardmodells vorhergesagt, die bestimmte Schwächen der Theorie beseitigen können. Es wird nach einzeln produzierten Quarks aus zwei verschiedenen Modellen gesucht, da für diesen Produktionsmodus höhere Wirkungsquerschnitte im untersuchten Massenbereich vorhergesagt sind als für die Paarproduktion. Die Suche beschränkt sich auf Zerfälle der Quarks in W-Bosonen und Top-Quarks, wobei letztere fast ausschließlich in W-Bosonen und Bottom-Quarks zerfallen. Verlangt man, dass eines der W-Bosonen leptonisch zerfällt, erhält man Endzustände mit einem Lepton (Elektron oder Myon in diesem Fall), mehreren Jets, von denen einer als von einem Bottom-Quark stammend identifiziert werden kann, und fehlender Energie in der Transversalebene, die durch das beim leptonischen Zerfall entstandene und nicht detektierbare Neutrino hervorgerufen wird. Die daraus berechnete invariante Masse des neuen Quarks wird zur Unterscheidung zwischen Signal und Untergrund verwendet. Die Suche wurde auf dem am LHC im Jahr 2012 aufgenommenen Datensatz von Proton-Proton-Kollisionen bei einer Schwerpunktsenergie von 8 TeV ausgeführt. Es wurde kein signifikanter Unterschied zum vorhergesagten Untergrund gemessen und deshalb Ausschlussgrenzen für Parameter der untersuchten Modelle berechnet. Da die vorgestellte Suche Gebrauch von der geboosteten Topologie der Signalereignisse im untersuchten Massenbereich macht, übertreffen die Ergebnisse bei Weitem die Ausschlussgrenzen für das angeregte Quarkmodell, die in der Vorgängersuche auf dem Datensatz von 2011 erhalten wurden und sind vergleichbar mit kürzlich auf dem Datensatz von 2012 mit dem CMS-Detektor gewonnenen Ergebnissen. Darüber hinaus ist es die erste Suche nach einzeln produzierten vektorartigen Quarks im untersuchten Modell.
A search for vector-like and excited down-type (Q = 1/3) quarks with the ATLAS detector is presented in this thesis. The existence of these quarks is predicted by various models beyond the Standard Model, motivated by some limitations of that theory. Quarks from two specific models are searched for in single production mode, as this is predicted to yield higher cross-sections than pair production in the investigated mass range. The search focuses on decays of the heavy quarks to a W boson and a top quark, the latter of which subsequently decays almost exclusively into another W boson and a bottom quark. Requiring one of the two W bosons to decay leptonically leads to final states containing exactly one lepton (electron or muon in this case), several jets, one of which can be identified as originating from a bottom quark, and some amount of missing energy in the transverse plane stemming from the neutrino of the leptonic W decay. The reconstructed mass of the heavy quark is used to discriminate between signal and background. This search was performed on 20.3 inverse femtobarns of proton-proton collision data collected at the Large Hadron Collider in the year 2012 with a centre-of-mass energy of 8 TeV. No significant excess of the data over the background could be observed and therefore exclusion limits were set on model parameters. The search presented here makes use of the boosted event topology that is prominent in the explored range of signal masses, allowing it to by far exceed the exclusion bounds obtained in the preceding search for the excited quark model on the 2011 data set, and producing results that are comparable to those from a recent search performed with the CMS detector on the 2012 data set. Additionally, it is the first search in the single production mode for that specific vector-like quark model.
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2

Bielski, Rafal. "Top quark pair production measurements in the single lepton channel using the ATLAS detector." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/top-quark-pair-production-measurements-in-the-single-lepton-channel-using-the-atlas-detector(ff46d1b0-0102-47d5-a60c-3a9e4ae07c07).html.

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Three measurements of top-quark pair production cross sections in proton-proton collisions at sqrt(s) = 13 TeV using data collected by the ATLAS experiment are presented. The single-lepton final states are used, where one electron or muon, two b-jets and two other jets can be identified. The inclusive ttbar production cross section is measured to be sigma(ttbar) = 817 +/- 13 (stat.) +/- 103 (syst.) +/- 88 (lum.) pb, which is in good agreement with predictions and with other measurements. Absolute and relative differential cross sections of ttbar production are also measured, showing an overall good agreement with predictions, except for the top-quark transverse momentum distribution. As already reported in measurements at lower proton-proton collision energies, this distribution is shifted towards higher momenta in all predictions with respect to the observations. Total and differential fiducial cross sections of ttbar production in association with heavy-flavour jets are also presented. All tested models are found to agree with data within the uncertainties of these measurements.
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3

Edmonds, Keith Morgan [Verfasser]. "Supersymmetry searches in the single lepton final state with the ATLAS detector / Keith Morgan Edmonds." Mainz : Universitätsbibliothek Mainz, 2012. http://d-nb.info/1019194596/34.

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4

Biedermann, Dustin. "Search for Single Production of Vector-like Quarks Decaying into Wb in pp Collisions at sqrt(s)=13 TeV with the ATLAS Detector." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21025.

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In dieser Dissertation wird die Suche nach einzeln erzeugten vektorartigen T-Quarks mit einer elektrischen Ladung +2/3 und Y-Quarks mit einer elektrischen Ladung von -4/3 vorgestellt. Diese exotischen Teilchen werden von verschiedenen Modellen jenseits des Standardmodells vorhergesagt, welche versuchen das Verständnis der elektorschwachen Symmetriebrechung zu erweitern und somit das Naturalness Problem zu lösen. Hierfür werden die in 2015 und 2016 bei einer Schwerpunktsenergie von 13 TeV und einer integrierten Luminosität von 36.1 inversen fb vom ATLAS Detektor am LHC aufgezeichneten Proton-Proton-Kollisionen ausgewertet. Die Ereignisselektion ist auf leptonisch zerfallende W-Bosonen der Y/T nach Wb Zerfälle ausgerichtet, weshalb ein hochenergetischer, von einem Bottom-Quark stammender Jet, ein einzelnes Lepton, ein in Vorwärtsrichtung emittierter Jet sowie fehlende transversale Energie, neben verschiedenen Isolationskriterien, verlangt wird. Es konnte keine signifikante Abweichung zur Vorhersage des Standardmodells gemessen werden. Aus diesem Grund wurden obere Grenzen for die Kopplungsstärke und den Mischungswinkel von T-Quarks in einem Singulett-Modell sowie Y-Quarks eines (B,Y)-Dublett bzw. (T,B,Y)-Triplett-Modells mit Quarks der dritten Generation des Standard Modells bestimmt. Hierbei wurden erstmalig Interferenzeffekte mit Standardmodellprozessen berücksichtigt. Die obere Grenze für den Mischungswinkel wurden für ein T-Singulett-Modell bei einer Masse von 800 GeV zu |sin(theta_L)|= 0.18, für ein Y eines (B,Y)-Dublett-Modells zu |sin(theta_R)|= 0.17 sowie für ein Y eines (T,B,Y)-Triplett-Modells zu |sin(theta_L)|= 0.16 bestimmt. Die ermittelten Grenzen innerhalb des (B,Y)-Dublett-Modells im Massenbereich 800 GeV bis 1250 GeV sind zu indirekten, aus elektroschwachen Präzisionsvariablen abgeleiteten Schranken kompetitiv.
This thesis presents a search for singly produced vector-like T quarks with charge +2/3 or Y quarks with charge -4/3. These exotic particles are predicted by several beyond-the-standard-model theories which try to shed light on the mechanism of electro-weak symmetry breaking, thus addressing the Naturalness Problem. The analysis is performed on a proton-proton collision data set with an integrated luminosity of 36.1 inverse fb at a centre-of-mass energy of 13 TeV recorded in 2015 and 2016 by the ATLAS detector at the LHC. The focus is on leptonically decaying W bosons from Y/T to Wb decays of the heavy quarks and the event selection requires a jet leading in transverse momentum and being b-tagged, exactly one lepton, a forward jet as well as missing transverse energy beside several isolation requirements. No significant deviation from the expected Standard Model background is observed. Therefore, upper limits on the coupling strength and mixing angle between third generation Standard Model quarks and a T from a singlet model as well as a Y from a (B,Y) doublet or a (T,B,Y) triplet model are computed using the CLs method. This search represents the first analysis in which the interference effects with the Standard Model background are taken into account. The smallest upper limits are found to be |sin(theta_L)|= 0.18 for a T singlet for a mass of 800 GeV, |sin(theta_R)|= 0.17 in the (B,Y) doublet case at 800 GeV and |sin(theta_L)|= 0.16 for the (T,B,Y) triplet model. The observed limits on the mixing parameter |sin(theta_R)| are competitive with indirect bounds from electroweak precision observables in the mass range between about 800 GeV and 1250 GeV.
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5

Mergelmeyer, Sebastian [Verfasser]. "Measurement of the Associated Production of a Single Top Quark and a W Boson in Single-Lepton Events with the ATLAS Detector / Sebastian Mergelmeyer." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/110718455X/34.

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6

Rehnisch, Laura [Verfasser], Heiko [Akademischer Betreuer] Lacker, Arno [Akademischer Betreuer] Straessner, and Johannes [Akademischer Betreuer] Haller. "Search for singly produced vector-like down-type quarks in single-lepton final states with ATLAS / Laura Rehnisch. Gutachter: Heiko Lacker ; Arno Straessner ; Johannes Haller." Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://d-nb.info/1100447555/34.

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7

Ferrara, Valentina. "Extraction of the top quark mass from the total top quark pair production cross section in the single lepton channel." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16727.

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In dieser Arbeit wird eine Messung des totalen {\ttb} Produktions-Wirkungsquerschnitts im Einzellepton-Kanal vorgestellt. Der Wirkungsquerschnitt wird mittels einer Profile-Likelihood-Anpassung von Templates bestimmt, welche \"uber einen Lieklihood-Klassifikator unter Benutzung von vier kinematischen Variablen konstruiert werden. F\"ur ein Top-Quark der Masse $m_t=172.5$ GeV ergibt sich ein gemessener Wirkungsquerschnitt von $178.9 \pm 12$ pb, welcher innerhalb einer Standardabweichung mit den aktuellsten theoretischen Vorhersagen \"uberein stimmt. Um die Massenabh\"angigkeit des experimentellen Wirkungsquerschnitts zu bestimmen, wird die Messung f\"ur sieben weitere Werte der Top-Quarkmasse im Bereich zwischen 140 GeV und 200 GeV wiederholt. Mittels Vergleich dieser Massenabh\"angigkeit mit theoretischen Vorhersagen h\"oherer Ordnung wird die Top-Quarkmasse ermittelt. Diese Methode erlaubt die Bestimmung von zwei verschiedenen theoretischen Massenparametern: der Top-Quarkmasse im On-Shell-Schema $m_t^{\mathrm{pole}}$ sowie der Masse im $\overline{MS}$-Schema $\overline{m}_t(\overline{m}_t)$. Der Messwert mit der h\"ochsten erhaltenen Genauigkeit liegt bei $m_t^{\mathrm{pole}} = 171.2\pm 4.5$ GeV, und wird durch Verwendung der derzeit pr\"azisesten Berechnungen h\"oherer Ordnung im $\overline{MS}$-Schema erhalten. Dieser Wert stimmt innerhalb einer Standardabweichung mit den derzeitig besten Mittelwert von Messungen der Top-Quarkmasse am Tevatron \"uberein.
A measurement of the total {\ttb} production cross section in the single lepton channel is presented. The cross section is extracted in a profile likelihood fit of templates constructed from a likelihood classifier using four kinematic variables. For a top quark of mass $m_t=172.5$ GeV, the measured cross section is $178.9 \pm 12$ pb. The measurement agrees within one-standard deviation with the latest theoretical predictions. The cross section measurement is repeated for seven other values of the top quark mass ranging from 140 GeV to 200 GeV to obtain the mass dependence of the experimental cross section. By comparing this with the mass dependence of different higher-order predictions, the top quark mass is extracted. This method allows the determination of two different theoretical mass parameters: the top quark mass in the on-shell scheme $m_t^{\mathrm{pole}}$ and in the $\overline{MS}$ scheme $\overline{m}_t(\overline{m}_t)$. The most precise measurement obtained is $m_t^{\mathrm{pole}} = 171.2\pm 4.5$ GeV, obtained when employing the most precise higher-order calculations in the $\overline{MS}$ scheme. This value agrees within one-standard deviation with the latest Tevatron average of the best top quark mass measurements.
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8

Arrubarrena, Paola [Verfasser], and Alexander [Akademischer Betreuer] Mann. "Searches for supersymmetric top squarks and Higgsinos in single-lepton final states with the ATLAS detector / Paola Arrubarrena ; Betreuer: Alexander Mann." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1239049579/34.

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9

Sperlich, Dennis. "Search for the production of a single excited b quark in the Wt final state with a single lepton in pp collisions at sqrt s = 13 TeV with the ATLAS detector." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://edoc.hu-berlin.de/18452/24063.

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In dieser Dissertation wird eine Suche nach einem angeregten $b$ Quark, $b^*$, durchgeführt. Für diese $b^*$ wird eine anomale Kopplung an Bosonen aus dem Standard Modell vorhergesagt. Diese Kopplung führt zu der Produktion in hochenergetischen Proton-Proton Kollisionen. In der Suche zielen wir auf Ereignisse, bei denen eines der zwei $W$ Bosonen in ein Elektron oder Muon zerfällt und das andere in ein Hadronenpaar. Da es nur ein Neutrino in diesem Prozess gibt, kann das ganze Ereigniss kinematisch rekonstruiert werden. Damit ist es möglich, die Masse des $b^*$ als diskriminierende Variable zu verwenden. Als Datenquelle dienen die Daten, die der ATLAS Detektor in den Jahren 2015 und 2016 bei Proton-Proton Kollisionen mit einer Schwerpunksenergie von $\sqrt s = \SI{13}{\tera\electronvolt}$ aufgezeichnet hat. Dabei entspricht diese Datenmenge einer integrierten Luminosität von $\L_{int} = \SI{36.1}{\femto\barn^{-1}}$. Da die Analyse auf hochmassige $b^*$ abziehlt, kann man davon ausgehen, dass das Hadronenpaar aus dem $W$ Zerfall in einen Jet mit großen Radius passt. Es wurde kein signifikanter Überschuss über den Untergrund gefunden. Damit können nur obere Ausschlussgrenzen bezüglich der Wirkungsquerschnitte in dem entsprechenden Zerfallskanal abgeleitet werden. Unter Annahme von einer Kopplungskonstanten von 1, sind Zerfälle von $b^*\to Wt$ bis zu einer Masse $m_{b^*,\mathrm{obs}}= \SI{2.5}{\tera\electronvolt}$ ausgeschlossen, wobei erwartet wurde, dass die Ausschlussmasse bei $m_{b^*,\mathrm{exp}}= \SI{2.4}{\tera\electronvolt}$ liegen würde.
A search for an excited $b$ quark, $b^*$, in events containing a top quark and a $W$ boson is investigated. These $b^*$ are predicted to have some anomalous couplings to Standard Model bosons aiding the production in high energy proton-proton collisions. The search is aiming for events, where one of the two $W$ bosons decays into an electron or muon, while the other decays hadronically. With only one neutrino, the event can be kinematically fully reconstructed. This enables the use of the mass of the $b^*$ as the discriminant variable. The data source under investigation is the data taken by the ATLAS detector at the LHC accelerator in the years 2015 and 2016 at a center-of-mass energy of $\sqrt s = \SI{13}{\tera\electronvolt}$. The combined dataset corresponds to an integrated luminosity of $\L_{int} = \SI{36.1}{\femto\barn^{-1}}$. The analysis targets high mass excited $b^*$ quarks, where the products of the hadronically decaying $W$ are contained within a large-radius jet. No significant excess over the expected background is observed and upper limits on the cross-section times branching ratio and coupling limits are derived. Assuming unit coupling, $b^*$ decaying into $Wt$ are excluded up to $m_{b^*,\mathrm{obs}}= \SI{2.5}{\tera\electronvolt}$, with an expected exclusion limit of $m_{b^*,\mathrm{exp}}= \SI{2.4}{\tera\electronvolt}$.
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10

Sperlich, Dennis [Verfasser]. "Search for the production of a single excited b quark in the Wt final state with a single lepton in pp collisions at sqrt s = 13 TeV with the ATLAS detector / Dennis Sperlich." Berlin : Humboldt-Universität zu Berlin, 2021. http://nbn-resolving.de/urn:nbn:de:kobv:11-110-18452/24063-4.

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11

Horner, Stephan [Verfasser], and Gregor [Akademischer Betreuer] Herten. "Search for Supersymmetry in single-lepton final states with the ATLAS detector and Improved background model for the search of new physics = Suche nach Supersymmetry in Einzel-Lepton-Endzuständen mit dem ATLAS-Detektor und Verbessertes Untergrundmodell für die Suche nach Neuer Physik." Freiburg : Universität, 2011. http://d-nb.info/1123459878/34.

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12

Handl, David [Verfasser], and Dorothee [Akademischer Betreuer] Schaile. "Search for top squark pair production in the 3-body decay mode with a single lepton final state with the ATLAS detector / David Handl ; Betreuer: Dorothee Schaile." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1196968594/34.

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13

Ferrara, Valentina [Verfasser], Ulrich Akademischer Betreuer] Husemann, Hermann [Akademischer Betreuer] [Kolanoski, and Wolfang [Akademischer Betreuer] Lohmann. "Extraction of the top quark mass from the total top quark pair production cross section in the single lepton channel / Valentina Ferrara. Gutachter: Ulrich Husemann ; Hermann Kolanoski ; Wolfang Lohmann." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://d-nb.info/1034123718/34.

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14

Henrichs, Anna Christine [Verfasser], Arnulf [Akademischer Betreuer] Quadt, and Ulrich [Akademischer Betreuer] Husemann. "Precision Measurements of the Top Quark Pair Production Cross Section in the Single Lepton Channel with the ATLAS Experiment / Anna Christine Henrichs. Gutachter: Arnulf Quadt ; Ulrich Husemann. Betreuer: Arnulf Quadt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://d-nb.info/1043611495/34.

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15

Peri, Francesco. "Search for charged Higgs bosons decaying into top and bottom quarks with single-lepton final states using pp collisions collected at a centre-of-mass energy of 13 TeV by the ATLAS detector." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19775.

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In dieser Arbeit wird die Suche nach geladenen Higgs Bosonen (H±) vorgestellt. Dafür wurden Proton–Proton Kollisionen, die bei einer Schwerpunktsenergie von 13 TeV in den Jahren 2015 und 2016 mit einer integrierten Luminosität von 36.1 fb−1 mit dem ATLAS-Experiment produziert wurden, untersucht. Die Existenz solcher geladener Higgs Bosonen wird in verschiedenen Modellen jenseits des Standardmodells vorhergesagt und ist auch dadurch motiviert, das dass Standardmodell nicht immer eine Erklärung für verschiedenste beobachtete Phänomene liefern kann. Diese Arbeit konzentriert sich auf geladene Higgs Bosonen, die eine höhere Masse als das top Quark besitzen und über H± → tb zerfallen. Die H± Produktion, in Verbindung mit einem top und einem bottom Quark pp → tbH±, wird im Massenbereich von 200 bis 2000 GeV untersucht. Die Suche nach H± in dieser Arbeit beschränkt sich auf Endzustände mit einem geladenen Lepton und mehreren Jets. Mit Hilfe eines boosted decision trees werden verschiedenste kinematische Variablen miteinander kombiniert, um dadurch das H± Signal besser von dem Standardmodell Untergrund unterscheiden zu können. Es wurde kein signifikanter Unterschied zum vorhergesagten Standardmodell-Untergrund gemessen und deshalb Ausschlussgrenzen für den Produktionswirkungsquerschnitt mal Verzweigungsverhältnis dieses H± Zerfalls berechnet. Weitere Ausschlussgrenzen wurden für den tanβ Parameter des MSSM Modells für die mhmod− und hMSSM Benchmark-Szenarien bestimmt. Die Ergebnisse dieser Arbeit übertreffen alle bisherigen Ausschlussgrenzen - insbesondere werden zum ersten Mal Erkenntnisse über den Massenbereich bis zu 2000 GeV gewonnen.
This thesis presents a search for charged Higgs bosons produced in proton–proton collisions at a centre-of-mass energy of 13 TeV, using 36.1 fb−1 of data collected by the ATLAS detector at the LHC in 2015 and 2016. The existence of charged Higgs bosons is predicted by various theories Beyond the Standard Model and it is motivated by the inadequacy of the Standard Model to explain some observed experimental phenomena. The work focuses on charged Higgs bosons heavier than the top quark and decaying via H± → tb. The production in association with a top and a bottom quark (pp → tbH±) is investigated in the mass range between 200 and 2000 GeV. A final state containing one charged lepton and jets is considered. Multiple kinematic variables are combined using a boosted decision tree (BDT) in order to separate signal and background. The output of the BDT is used to perform a profile likelihood fit of the Monte Carlo predictions to the observed data. No significant excess of events above the expected Standard Model background is observed, therefore upper limits are set for the cross-section of the charged Higgs boson production times the branching fraction of its decay. Limits are also provided for the tanβ parameter of the MSSM, in the mhmod− and hMSSM benchmark scenarios. The work improves the reach of all previous searches, including for the first time masses ranging up to 2000 GeV.
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16

Sabatini, Paolo [Verfasser]. "Search for the production of four top quarks in proton-proton collisions at √s=13 TeV in the single lepton and opposite-sign dilepton channels with the ATLAS detector at the Large Hadron Collider / Paolo Sabatini." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1214887120/34.

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17

Atlay, Naim Bora [Verfasser]. "Differentiating top-quark - photon coupling: inclusive and differential cross-section measurements of top-quark pair production in association with a photon in the single lepton channel in pp collisions data at √s 8TeV with the ATLAS experiment / Naim Bora Atlay." Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/1163453919/34.

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Peri, Francesco [Verfasser], Thomas [Gutachter] Lohse, Johannes [Gutachter] Haller, and Heiko [Gutachter] Lacker. "Search for charged Higgs bosons decaying into top and bottom quarks with single-lepton final states using pp collisions collected at a centre-of-mass energy of 13 TeV by the ATLAS detector / Francesco Peri ; Gutachter: Thomas Lohse, Johannes Haller, Heiko Lacker." Berlin : Humboldt-Universität zu Berlin, 2019. http://d-nb.info/1182541593/34.

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19

Korcsák-Gorzó, Katherine. "High Pτ leptons and single W boson production at HERA." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670032.

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20

Mantoani, Matteo [Verfasser], Arnulf [Akademischer Betreuer] [Gutachter] Quadt, and Stan [Gutachter] Lai. "Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at √s = 13 TeV with the ATLAS experiment at the LHC / Matteo Mantoani ; Gutachter: Arnulf Quadt, Stan Lai ; Betreuer: Arnulf Quadt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1136471448/34.

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Serkin, Leonid [Verfasser], Arnulf [Akademischer Betreuer] [Gutachter] Quadt, and Stan [Gutachter] Lai. "Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at √s = 8 TeV with the ATLAS experiment at the LHC / Leonid Serkin. Betreuer: Arnulf Quadt. Gutachter: Arnulf Quadt ; Stan Lai." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1111883556/34.

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22

Kyriazis, George. "THE EFFECTS OF A SINGLE EXERCISE BOUT ON PLASMA LEPTIN CONCENTRATION IN OBESE MALES." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3682.

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Recent findings suggest that leptin may be regulated in response to abrupt changes in energy homeostasis. Therefore, it is conceivable that transient changes in energy balance induced by exercise may also regulate leptin synthesis and secretion. As such, we hypothesized that acute increases energy expenditure (i.e. exercise), may regulate leptin concentrations in obese individuals. Fifteen healthy obese males underwent either a single exercise session of moderate intensity (58.4 % ± 4.0 of VO2max) for 60 min (n=8), or served as controls (n=7). The exercise session elicited an energy expenditure of 567±80 Kcal. No significant changes in plasma leptin (pre 23.5± 30.2; post 24.3± 34.3; 24h-post 34.9± 66.6; 48h-post 33.8±64.0 ng/ml), or insulin levels (pre 16.1± 9.2 vs. post 8.1± 9.1; 24h-post 14.3± 9.9; 48h-post 13.8± 10.2 ?U/ml) were detected immediately after the intervention. Baseline plasma leptin levels were positively correlated with BMI (r=0.65; p<0.01), body weight (r=0.64; p<0.01), % body fat (r=0.90; p<0.01) and were negatively correlated with VO2max (r=-0.82; p<0.01). The results of the present study suggest that acute exercise of moderate intensity and duration may not affect leptin concentration.
M.A.
Department of Child, Family and Community Sciences
Education
Physical Education
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23

Weiland, Cedric. "Effects of fermionic singlet neutrinos on high- and low-energy observables." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00922999.

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In this doctoral thesis, we study both low- and high-energy observables related to massive neutrinos. Neutrino oscillations have provided indisputable evidence in favour of non-zero neutrino masses and mixings. However, the original formulation of the Standard Model cannot account for these observations, which calls for the introduction of new Physics. Among many possibilities, we focus here on the inverse seesaw, a neutrino mass generation mechanism in which the Standard Model is extended with fermionic gauge singlets. This model offers an attractive alternative to the usual seesaw realisations since it can potentially have natural Yukawa couplings (O(1)) while keeping the new Physics scale at energies within reach of the LHC. Among the many possible effects, this scenario can lead to deviations from lepton flavour universality. We have investigated these signatures and found that the ratios R_K and R_π provide new, additional constraints on the inverse seesaw. We have also considered the embedding of the inverse seesaw in supersymmetric models. This leads to increased rates for various lepton flavour violating processes, due to enhanced contributions from penguin diagrams mediated by the Higgs and Z bosons. Finally, we also found that the new invisible decay channels associated with the sterile neutrinos present in the supersymmetric inverse seesaw could significantly weaken the constraints on the mass and couplings of a light CP-odd Higgs boson.
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Mellenthin, Johannes Donatus [Verfasser], Arnulf [Akademischer Betreuer] Quadt, Arnulf [Gutachter] Quadt, and Stan [Gutachter] Lai. "Observation of the Standard Model Higgs boson produced in association with a pair of top quarks at $\sqrts} = 13 \, \textTeV}$ with the ATLAS experiment at the LHC with emphasis on the decay of the Higgs boson into a $b\bar{b}$-pair in the single-lepton channel / Johannes Donatus Mellenthin ; Gutachter: Arnulf Quadt, Stan Lai ; Betreuer: Arnulf Quadt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1198481234/34.

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25

Antonelli, Stefano <1969&gt. "Study of production of high-PT leptons and limits on single top production at HERA." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2026/.

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26

Fujiwara, Clarissa Tamie Hiwatashi. "Efeito dos polimorfismos nos genes da leptina e do receptor da leptina sobre a compulsão alimentar em crianças e adolescentes obesos." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/5/5135/tde-30102014-104249/.

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INTRODUÇÃO: A obesidade na infância e adolescência representa uma epidemia global e figura como um problema de saúde pública proeminente de prevalência crescente. A obesidade frequentemente está associada à compulsão alimentar periódica (CAP) e componentes genéticos participam de sua etiologia multifatorial. Polimorfismos de nucleotídeo único (SNPs) no gene da leptina (LEP) e do receptor da leptina (LEPR) podem modificar a expressão da leptina e de suas vias de sinalização e, consequentemente, alterar a regulação do apetite e da saciedade, contribuindo assim para a etiopatogenia e manutenção da CAP. O objetivo deste trabalho foi investigar a influência dos polimorfismos rs7799039 (G > A) no gene LEP e rs1137100 (A > G), rs1137101 (A > G) e rs8179183 (G > C) no gene LEPR sobre a CAP em crianças e adolescentes obesos, além de caracterizar a população quanto à CAP e verificar a associação dos SNPs com o risco cardiometabólico (RCM) e a obesidade. MÉTODOS: Estudo transversal que incluiu 465 crianças e adolescentes obesos com idade entre 7 e 19 anos avaliados quanto a variáveis antropométricas e metabólicas. Os fatores de RCM consistiram de hipertensão arterial sistêmica, glicemia de jejum alterada, HDL-colesterol baixo e hipertrigliceridemia. A CAP foi avaliada por meio da Escala de Compulsão Alimentar Periódica (ECAP). Para investigar o efeito dos SNPs no risco para a obesidade foi incluído um grupo controle composto por 135 crianças e adolescentes eutróficos. A genotipagem foi realizada por PCR em tempo real e para análise dos SNPs, adotou-se o modelo dominante. Foi calculado o desequilíbrio de ligação entre os SNPs e estimada as frequências dos haplótipos. As comparações entre os grupos foram realizadas estratificadamente por gênero e estádio puberal. Para avaliar a magnitude do risco dos SNPs sobre a CAP e a obesidade foi realizada regressão logística ajustada para variáveis de confusão (idade, Z-IMC e estádio puberal). RESULTADOS: As crianças e adolescentes obesos (12,5 ± 2,9 anos; 52,7% meninas) classificados com CAP apresentaram maior adiposidade e a frequência da CAP foi mais elevada no gênero feminino (OR= 2,146; IC 95% 1,461-3,152; p < 0,001). A frequência do alelo A do rs7799039 foi mais elevada no grupo de obesos (OR= 1,530; IC 95% 1,022-2,292; p= 0,039) e o alelo associou-se ao maior nível de leptina e colesterol total em meninas e à maior glicemia em meninos (p < 0,05). No rs1137100 e o rs1137101, a presença do alelo G em meninas conferiu risco para a hipertrigliceridemia (OR= 1,926; IC 95% 1,010-3,673; p= 0,047 e OR= 2,039; IC 95% 1,057-3,931; p= 0,033, respectivamente). O alelo C do rs8179183 relacionou-se, em meninas, à relação cintura-estatura e glicemia mais elevadas e, em meninos, ao maior percentil de pressão arterial diastólica, glicemia, colesterol total e LDL-colesterol (p <0,05). CONCLUSÃO: Os polimorfismos não foram associados à compulsão alimentar periódica. A CAP foi relacionada ao pior grau de adiposidade e o maior risco foi observado no gênero feminino. O SNP rs7799039 no gene LEP conferiu risco para obesidade, enquanto o rs1137100, rs1137101 e rs8179183 no gene LEPR relacionaram-se ao pior perfil cardiometabólico em crianças e adolescentes obesos
INTRODUCTION: Obesity during childhood and adolescence represents a global epidemic and consists in a prominent public health issue of increasing prevalence. Obesity is frequently associated with binge eating (BE) and genetic factors participate of its multifactorial etiology. Single nucleotide polymorphisms (SNPs) in the leptin (LEP) and leptin receptor (LEPR) genes may modify the leptin expression and its signaling pathways and, consequently, alter appetite and satiety regulation, thus contributing to the etiopathogeny and maintenance of BE. The aim of this study was to investigate the influence of polymorphisms rs7799039 (G > A) in the LEP gene and rs1137100 (A > G), rs1137101 (A > G) and rs8179183 (G > C) in the LEPR gene on BE in obese children and adolescents, besides characterize the population regarding to BE and examine the association of SNPs with cardiometabolic risk (CMR) and obesity. METHODS: Cross-sectional study in which 465 obese children and adolescents aged from 7 to 19 years were enrolled and had anthropometric and metabolic variables assessed. The CMR factors consisted of systemic hypertension, impaired fasting glucose, low HDL-cholesterol levels and hypertriglyceridemia. The BE was evaluated through the Binge Eating Scale (BES). To investigate the effect of SNPs on obesity risk, a control group of 135 eutrophic children and adolescents was enrolled. Genotyping was performed by real-time PCR and for the SNPs analysis, the dominant model was adopted. The linkage disequilibrium between SNPs was calculated and the haplotype frequencies were estimated. Comparisons between groups were performed stratified by gender and pubertal stage. To assess the risk magnitude for the SNPs on BE and obesity, logistic regression adjusted for confounding variables (age, Z-BMI and pubertal stage) was performed. RESULTS: Obese children and adolescents (12.5 ± 2.9 years, 52.7% girls) classified with BE showed greater adiposity and BE frequency was higher among females (OR= 2.146; 95% CI 1.461-3.152; p < 0.001). The observed frequency of A allele of rs7799039 was a higher in the obese group (OR= 1.530; 95% CI 1.022-2.292; p= 0.039) and the allele was associated with higher leptin and total cholesterol levels in girls and higher glucose levels in boys (p < 0.05). For the rs1137100 and rs1137101, the presence of the G allele among girls, conferred risk for hypertriglyceridemia (OR= 1.926; 95% CI 1.010-3.673; p= 0.047 and OR= 2.039; 95% CI 1.057-3.931; p= 0.033, respectively). The C allele of rs8179183 was associated, among girls, with a higher waist-to-height ratio and glucose levels and, among boys, with greater diastolic blood pressure percentile, glucose, total cholesterol and LDL-cholesterol levels (p < 0.05). CONCLUSION: Polymorphisms were not associated with binge eating. BE was related with a more severe adiposity and an increased risk was observed among females. The SNP rs7799039 in the LEP gene contributed to the risk of obesity, whereas the rs1137100, rs1137101 and rs8179183 in LEPR gene were related to a worse cardiometabolic profile in obese children and adolescents
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27

Kuo, Alice Yi-Wen. "Genomic and Physiological Differences for Ghrelin and Leptin Receptor in Lines of Chickens Selected for High and Low Body Weight." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/30045.

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Autonomic nervous system (ANS) activity is related to body weight regulation. Based on the hypothesis that Most Obesities kNown Are Low In Sympathetic Activity (MONA LISA), it has been suggested that most obese subjects and animals have low sympathetic nervous system activity. Leptin, leptin receptor, and ghrelin genes influence the ANS regulation of body weight and food intake. The aim of this study was to investigate whether there are differences in leptin, the leptin receptor, or ghrelin regulation between lines of chickens selected for high (HWS) or low body weight (LWS). Intraperitoneal injections of reserpine were administrated to chickens from the HWS and LWS lines. Body weight and food intake were then compared to evaluate ANS regulation. While reserpine caused a transitory decrease in food intake and body weight in both lines, the magnitude of the change was greater in the HWS than in the LWS chickens. However, chickens from the LWS line exhibited greater catecholamine and indoleamine level changes in response to reserpine than those from the HWS line. Therefore, HWS chickens were more sensitive to the body weight-reducing effects of reserpine than LWS lines, while LWS chickens appeared to have greater sympathetic nervous system activity. Food and water intakes were differentially affected in HWS and LWS chickens in response to intracerebroventricular administration of human recombinant leptin. Leptin caused a linear decrease in food intake in the LWS line, but no effect on food intake in the HWS lines. The HWS chickens tended to have reduced water intake following leptin administration. These results suggest that the leptin receptor, or the down-stream neuropeptide regulation pathway mediating the effect of leptin; may be different between chickens from the HWS and LWS lines. Leptin, insulin like growth factor (IGF)-1, and IGF-2 concentrations in the plasma of HWS and LWS lines of chickens were evaluated. Leptin, IGF-1 and IGF-2 levels were significantly higher in the LWS than HWS chickens. The HWS female leptin concentrations were significantly lower than in HWS males or LWS females. Male chickens had greater IGF-1 concentrations in the plasma than female chickens. However, the concentration of IGF-2 did not differ between sexes. The difference in leptin concentrations in these lines and sexes may explain the differences in age of sexual maturity. Different IGF-1 and IGF-2 concentrations may be involved in the obese and anorexic conditions, fast and slow growth, and high and low food consumption found in these two lines of chickens. Differences in the gene sequence of the leptin receptor were observed in HWS and LWS lines of chickens. A single nucleotide polymorphism (SNP) in the intron between exon 8 and 9 introduced a restriction site for the enzyme Sel I in the HWS, but not the LWS line. Two SNP were detected in the leptin receptor cDNA region at nucleotides 189 and 234. At nucleotide 189, the LWS line has both a homozygous (T-T) and heterozygous (C-T), whereas the HWS line has only homozygous (T-T) form. The SNP found in nucleotide 234 introduces a restriction site Mse I in the HWS, but not the LWS line. These specific changes may be directly involved or closely linked to differences between the two lines in either the coding or regulatory domains of the leptin receptor. Differences in the leptin receptor gene expression between HWS and LWS lines of chickens in various organs and ages were observed. Leptin receptor expression in the whole brain was significantly different between sexes at 28 days-of-age in the HWS and LWS lines. The LWS line had higher leptin receptor gene expression in the liver at 2 days-of-age than at 56 and 363 days-of-age, but no differences were observed in the HWS line. In addition, at 2 days-of age, liver leptin receptor gene expression was higher in LWS than HWS chickens, but the reverse was observed at 363 days-of age. In adipose tissue, leptin receptor expression was higher in the LWS than HWS line. Leptin receptor expression in adipose tissue was greater at 363, than 28 and 56 days-of-ages. Our results showed that changes in the regulation of leptin and the leptin receptor were associated with sex, age, and growth. Differences in the ghrelin gene in the HWS and LWS lines under different feeding conditions were investigated. Both HWS and LWS chickens have six extra base pairs in the 5'-untranslated region. The LWS male ghrelin gene expression was significantly lower than in the LWS female and HWS male. The 84 day-old males had lower gene expression than 84 day-old females and 363 day-old males. When comparing different feeding methods, females allowed ad libitum feed consumption had a lower cycle threshold cycle number (CT) ratio than males allowed ad libitum feeding or fasted females. However, the inflection point cycle number of ad libitum fed females was lower than that of the ad libitum fed males, but greater than the fasted females. Ghrelin gene expression was different between the two lines of chickens, and the expression of ghrelin in chickens was influenced by body weight selection, sex, age, and feeding condition.
Ph. D.
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28

Breiner, Ryan Michael. "Association of single nucleotide polymorphisms in the leptin gene and segregation by ultrasound backfat at weaning on carcass performance in steers." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1400.

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29

Zelenskiy, Svetlana. "Effect of dietary glycemic load and single nucleotide polymorphisms in the adipogenesis pathway on colon cancer susceptibility." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1386349030.

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30

Negroni, Sylvain. "Etude de la détection de la supersymétrie par production de quark top en singlet. Détermination de l'échelle d'énergie des calorimètres électromagnétiques auprès des collisionneurs hadroniques." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2000. http://tel.archives-ouvertes.fr/tel-00001476.

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Dans le cadre des théories au delà du modèle standard, au cours de la prochaine dizaine d'années, deux accélérateurs exploreront le domaine d'énergie du TeV, où sont attendus des signes de cette nouvelle physique. En 2001, le Tevatron, collisionneur proton-antiproton du Femilab à Chicago, redémarrera avec une énergie de 2 TeV et une luminosité augmentée et sera première étape dans cette voie. Elle sera suivie en 2005 par le nouvel accélérateur du CERN, le collisionneur proton-proton LHC, dont l'énergie atteindra 14 TeV. Deux expériences, D0 pour le Tevatron et ATLAS pour le LHC, partagent de nombreuses similitudes dans leurs choix techniques. Cette particularité permet d'envisager des études qui sont facilement transposables d'une expérience à l'autre, et c'est dans cette optique que j'ai pris part au cours de ma thèse à ces deux expériences. A l'aide d'un générateur Monte-Carlo spécialement écrit pour la simulation de la production du quark top par R-parité violée, j'ai étudié les potentiels de découverte de la supersymétrie pour l'expérience ATLAS. Compte-tenu des limites actuelles sur les couplages RPV et des hypothèses prises en compte, la production de s-quark en voie résonnante peut-être détectée au LHC pour des masses allant de 300 à 900 GeV. Réciproquement, l'absence de signaux permettra d'augmenter les limites sur les produits de couplages considérés d'un facteur 10 au moins. Enfin , en cas de détection de s-quarks, la masse de ceux-ci peut-être mesurée directement avec une erreur de l'odre du %. Dans le cadre de DO, j'ai proposé un aglorithme de calibration pour le calorimètre électromagnétique, utilisant des événements physiques Z -> ee. Avec une statistique de 7000 événements, correspondant à un ou deux mois de fonctionnement du Tevatron, la calibration du détecteur peut être ramenée de 1% à 0,5%
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Altheimer, Andrew David. "A Search for tt Resonances in the Single Lepton Final State with the ATLAS Experiment." Thesis, 2014. https://doi.org/10.7916/D8XG9PBD.

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A search for undiscovered particles decaying into top-antitop quark pairs produced in proton-proton collisions with the ATLAS experiment at the Large Hadron Collider utilizing 20.3 fb$^-1$ of data collected at $\sqrt{s}=8$ \tev\ center-of-mass energy during the 2012 data taking period is presented. The invariant mass spectrum of events containing multiple jets, exactly one lepton, and missing transverse energy and which are consistent with the decay of a top-antitop quark pair is studied and found to be consistent with that predicted by the Standard Model. Upper limits on the production cross section times branching ratio of several benchmark signal models are set at a 95\% confidence level.
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Henrichs, Anna Christine. "Precision Measurements of the Top Quark Pair Production Cross Section in the Single Lepton Channel with the ATLAS Experiment." Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-F083-5.

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33

Sabatini, Paolo. "Search for the production of four top quarks in proton-proton collisions at $\sqrt{s}=13$ TeV in the single lepton and opposite-sign dilepton channels with the ATLAS detector at the Large Hadron Collider." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1439-5.

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34

Serkin, Leonid. "Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at sqrt{s} = 8 TeV with the ATLAS experiment at the LHC." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-8804-4.

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Mantoani, Matteo. "Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at √s = 13 TeV with the ATLAS experiment at the LHC." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3E97-C.

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36

Mellenthin, Johannes Donatus. "Observation of the Standard Model Higgs boson produced in association with a pair of top quarks at $\sqrt{s} = 13 \, \text{TeV}$ with the ATLAS experiment at the LHC with emphasis on the decay of the Higgs boson into a $b\bar{b}$-pair in the single-lepton channel." Doctoral thesis, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-128B-A.

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