Дисертації з теми "Higgs Sector"
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Cabi, Serkan. "Cosmology of hidden sector with Higgs portal." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52778.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 67-75).
In this thesis, we are investigating cosmological implications of hidden sector models which involve scalar fields that do not interact with the Standard Model gauge interactions, but couple directly to the Higgs field. We particularly focus on their relic particle density as a candidate for dark matter. For the case of hidden sector without a gauge field we have improved the accuracy of the bounds on the coupling constant and give bounds on the Lagrangian parameters. Models with Abelian and non-Abelian gauge fields are also studied with relic density bounds, BBN and galactic dynamics constraints. Several discussions on phase transitions and alternative dark matter candidates are included.
by Serkan Cabi.
Ph.D.
Thrasher, Richard Keith. "Extensions of the Standard Model Higgs Sector." W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1550153848.
Повний текст джерелаRiembau, Marc. "Exploration of the higgs sector after its discovery." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/663947.
Повний текст джерелаThe discovery of the Higgs boson culminates a 40-year long hunt and completes a theoretical framework under which almost all collider data can be consistently explained. At the same time, paradoxically, the con rmation of an apparent mass gap above the electroweak scale exacerbates the problem of the electroweak hierarchy. In the search of a description of the world that simpli es the patterns and symmetries of the Standard Model, the exploration of the TeV scale and in particular the study of the Higgs boson will play a central role. In this thesis we explore the possibilities that the LHC and future colliders will bring, with particular emphasis on the determination of the Higgs self-coupling. We also consider the pair production of electroweak bosons as a probe of the Goldstone interactions in the Higgs doublet, and show its relevance as a way to improve the Z pole measurements and its interplay with other LHC searches. Finally, we focus on how the electron’s electric dipole moment can set strong constraints on models where the Higgs arises as a composite state.
Munir, Shoaib. "The Higgs sector of non-minimal supersymmetric models." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439369.
Повний текст джерелаPattori, Andrea. "Unveiling New Physics Hints through the Higgs Sector." Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3426662.
Повний текст джерелаPer svelare i misteri della fisica oltre il Modello Standard si deve innanzitutto capire appieno il Modello Standard stesso ed in particolare il settore di Higgs, di gran lunga il meno compreso. In questa dissertazione delineiamo due possibili approcci a tale riguardo: si può assumere un’atteggiamento fenomenologico, cercando di parametrizzare in maniera ottimale gli esperimenti ad LHC, oppure un punto di vista più formale cercando di aumentare la nostra comprensione teorica del settore di Higgs (nella speranza di comprenderne i misteri). Nella prima parte di questa dissertazione, affrontiamo la questione delle correzioni infrarosse nella fisica degli acceleratori di particelle. Il nostro obiettivo è una descrizione generale di tali correzioni, da poter utilizzare in modo “model-independent” quando si cerca di caratterizzare la fenomenologia di nuova fisica ad LHC. Innanzitutto ci focalizziamo sulle correzioni elettromagnetiche (bremsstrahlung), fornendo un formalismo compatto e generale per descrivere la bremsstrahlung da correnti fermioniche neutre. Esemplifichiamo poi i nostri risultati tramite l’esempio del decadimento “h -> 2e 2mu”. In seguito ampliamo la nostra discussione per includere le correzioni elettrodeboli, limitandoci ai cosiddetti contributi doppio-logaritmici (importanti per i processi di produzione dell’Higgs) e concentrandoci sul caso di produzione associata Higgs-Z e Higgs-W. Nella seconda parte di questa dissertazione adottiamo un approccio complementare e effettuiamo uno studio teorico di una classe di teorie supersimmetriche chiamate “high-scale SUSY”. Sfruttando la struttura estremamente rigida del settore di Higgs in tali teorie, traiamo conclusioni molto interessanti riguardo la loro fattibilità nel piano (“massa dell’Higgs”, “massa del top”).
Williams, Karina E. "The Higgs sector of the complex minimal supersymmetric standard model." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2129/.
Повний текст джерелаFlament, Jean-Baptiste. "Phenomenology of the scalar sector beyond the standard model." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10178/document.
Повний текст джерелаWith the discovery of a new particle in July 2012 by the CMS and ATLAS experiments, with properties resembling those of a boson predicted about 50 years earlier by theorists, the search for physics outside of the standard model of particle physics (SM) has made a big step. Indeed, the existence of this piece of the electroweak symmetry breaking proved wrong many theories, while giving more credit to the SM. However, because of some observations it fails to match, we know the SM cannot be the final word, and it is hoped that the study of this new particle will be a path to new sectors of physics. After a brief description of the SM and of the statistics of particle physics, we will present a way to parametrise the couplings measured at CERN, in order to constrain, through these couplings, more fundamental models describing physics beyond the standard model. This parametrisation, focusing on loop-induced couplings, would allow to lift a correlation existing between parameters currently used by experimentalists. We will then study the feasibility of a search for another scalar, lighter than the one discovered and which would have escaped previous searches, through the use of the same parametrisation. In two models, the 2HDM and the NSSSM, values of parameters yet unconstrained are shown.Finally, we will see that this scalar can also influence the joint production of two weak gauge bosons. We will show that the analysis of this process can be used in a coherent manner with on-shell Higgs measurements to constrain its couplings through our parametrisation. We will then end with a brief look at some limitation of this approach, before suggesting ways to overcome them
Zucchetta, Alberto. "Searches for signatures of an extended Higgs sector in final states with leptons and Higgs to bb decays at CMS." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424106.
Повний текст джерелаIl modello standard (SM) delle particelle elementari, verificato sperimentalmente ad alta precisione, prevede l’esistenza di una particella scalare, il bosone di Higgs, grazie al quale avviene la rottura di simmetria elettrodebole ed è possibile spiegare le masse non nulle dei fermioni. La ricerca del bosone di Higgs è stata perseguita in passato da diversi esperimenti ai collisori LEP II e Tevatron, ma sempre con esito negativo. Solo nell’anno 2011, all’acceleratore LHC gli esperimenti ATLAS ed CMS hanno cominciato ad osservare le prime evidenze dell’elusiva particella, per poi confermane definitivamente la scoperta nel 2012. Tuttavia, pur essendo l’esistenza e le caratteristiche osservate del bosone di Higgs l’ennesima verifica sperimentale della validità del modello standard, esistono fenomeni naturali che esso non è in grado di spiegare, come ad esempio la massa dei neutrini o la materia oscura. Diverse estensioni del modello standard sono state proposte; diverse tra le più accreditate prevedono non uno, ma più bosoni. Con l’entrata a regime di LHC nel 2011 e le prime evidenze di un bosone di Higgs, una delle domande fondamentali a cui dare risposta era se il segnale che si stava osservando fosse dovuto al bosone di Higgs dello SM, oppure al più leggero dei diversi bosoni previsti dalle teorie oltre il modello standard. La risposta poteva venire sia dalla misura degli accoppiamenti dell’Higgs alle particelle dello SM, sia osservando processi e decadimenti non previsti dallo SM, o misurati con una frequenza maggiore dell’atteso. La produzione di un bosone di Higgs in associazione con quarks b, e il suo successivo decadimento in una coppia di quark b, è un processo difficilmente osservabile nel modello standard, pertanto la sua osservazione averebbe significato la presenza di nuova fisica. Precedenti ricerche a Tevatron hanno evidenziato un lieve eccesso in questo canale. In seguito alla scoperta del bosone di Higgs nel Luglio 2012 da parte degli esperimenti CMS e ATLAS, la conoscenza delle proprietà di questa particella, ivi compresa la sua massa, diventano informazioni che possono essere utilizzate per aumentare la sensibilità a ricerche di processi di nuova fisica. Uno dei canali che beneficia di questa informazione è la ricerca di un bosone pseudoscalare A, in particolare nel suo decadimento in un bosone Z e un bosone di Higgs leggero h, che si assume essere quello di massa 125 GeV recentemente scoperto. Lo stato finale consiste in una coppia di elettroni o muoni originati dal decadimento del bosone Z, e una coppia di quark b dal decadimento dell’Higgs. Questo canale, non previsto dallo SM, permette di sondare una regione dello spazio dei parametri di teorie oltre il modello standard per certi versi complementare a quella del canale con molti b nello stato finale.
Katanaeva, Alisa. "Holography applications in the strongly coupled sector: from QCD to the new physics." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/671798.
Повний текст джерелаEn esta tesis estudiamos sectores fuertemente acoplados en el Modelo Estándar (SM) y más allá (BSM) dentro del enfoque holográfico. Nuestro propósito es sobresalir el método en la aplicación a la física mejor estudiada y luego utilizar el conocimiento acumulado en el ámbito que está fuera del alcance de los experimentos contemporáneos. Las ideas holográficas aparecieron después de que se hiciera la observación de Bekenstein y Hawking sobre la naturaleza de la entropía del agujero negro. El principio holográfico general se formuló de la siguiente manera: todo el contenido de información de una teoría de la gravedad cuántica en un volumen dado se puede codificar en una teoría eficaz sobre la frontera. La correspondencia anti-de Sitter / teoría conforme de campos (AdS/CFT) combinó holografía y dualidades (por esa razón también se conoce con el nombre de dualidad gauge/gravedad) en una interesante propuesta para la investigación de la teoría de cuerdas y los aspectos de la gravedad cuántica. Sin embargo, pronto se descubrió que la teoría supersimétrica $ N = 4 $ de Yang-Mills, por la que Maldacena ha encontrado un la teoría dual de cuerdas, es en cierto modo similar a la cromodinámica cuántica (QCD) en el régimen fuertemente acoplado. Eso desvió la atención a la parte gauge de la correspondencia. Sorprendentemente, la teoría de cuerdas es más fácil de resolver que la teoría mundana de quarks y gluones porque se conjetura que está en el límite semiclásico y débilmente acoplado. Existen pocas herramientas teóricas para estudiar regímenes fuertemente acoplados. Para QCD, el más conocido es la formulación lattice de primer principio. Reveló mucho sobre la naturaleza de QCD. Por ejemplo, señaló que la transición de desconfinamiento de los estados de hadrones ligados al plasma de quark-gluones ocurre como un cruce suave. Desafortunadamente, no es omnipotente: además de las restricciones tecnológicas y la complejidad cada vez mayor de los cálculos numéricos, existe, por ejemplo, un problema mucho más profundo relacionado con la inclusión del potencial químico de los quarks finito. Este último define uno de los ejes del diagrama de fase QCD, de modo que la lattice QCD no puede analizarlo en su totalidad. A su vez, la holografía se puede utilizar para abordar varios aspectos de QCD: espectros de mesón, glueball y barión, interacciones hadrónicas y el proceso de hadronización en colisionadores, confinamiento y ruptura de simetría quiral, materia hadrónica en condiciones externas extremas. Sin embargo, existen varias limitaciones en QCD que aparecen en construcciones similares a AdS/CFT. Primero, se supone que debe estar en el límite de $N_c$ grande. Independientemente de la holografía, se demostró que este límite puede verse como una versión exagerada de QCD tricolor común: el número de excitaciones radiales de un estado dado es infinito, cada una de ellas es infinitamente estrecha, el desconfinamiento representa una transición de fase real, etc. En segundo lugar, la propiedad de confinamiento no se puede combinar con CFT; uno debería encontrar una manera de romper la invariancia conforme e introducir una escala QCD $ \ Lambda_ {QCD} $. No hace falta decir que se desconoce la teoría dual de cadena exacta para QCD. En esta tesis utilizamos el llamado enfoque holográfico bottom-up (AdS / QCD) que fue desarrollado para superar las dificultades teóricas y que se centra en la descripción exitosa de la fenomenología QCD. En AdS / QCD se construyen modelos de cinco dimensiones siguiendo las reglas del diccionario AdS / CFT. Los campos 5D corresponden a los operadores de interpolación en 4D y pueden considerarse como la conexión entre la fuente sobre la frontera y un punto en el volumen. Las funciones de Green, que definen la teoría 4D, se pueden calcular a partir de la acción 5D debido a la correspondencia entre las funciones de partición. Al mismo tiempo, la representación de Kaluza-Klein de un campo 5D contiene los grados de libertad físicos reales 4D con los números cuánticos de los operadores duales. Se puede extraer el espectro de masas de estos modos. La invariancia conforme del espacio $ AdS_5 $ se rompe mediante la introducción manual de la pared en la quinta dirección ($ z $). Básicamente, se pueden considerar paredes de dos tipos: la pared dura, que es solo un corte a una distancia finita en la dirección $ z $, y la pared blanda, donde se introduce un perfil exponencial en la acción para suprimir cualquier contribución en $ z $ -infinito. Hay esfuerzos para aplicar la holografía en varios sistemas físicos, incluso tan desconectados de la teoría de cuerdas como la física de la materia condensada. Nuestro interés particular es la incorporación de modelos AdS / QCD en el ámbito de la física BSM. Hay varias ideas sobre cómo podrían producirse dinámicas fuertes allí. Nos centramos en los modelos de Higgs compuesto (CH), donde la nueva interacción fuerte une a los hiper-fermiones en estados compuestos a energías TeV, en paralelo a QCD que une quarks de SM en mesones y bariones. Este nuevo sector a la escala energética de varios TeV puede resolver el problema de naturalidad del SM al precio de una afinación relativamente pequeña. Además, proporciona predicciones BSM dentro del alcance experimental del futuro cercano. Por lo tanto, en esta tesis informamos sobre nuestras investigaciones de QCD y CH dentro del enfoque holográfico bottom-up. Una revisión de una amplia gama de temas es un requisito previo en este tipo de estudio que combina construcciones teóricas sofisticadas y análisis de datos fenomenológicos. En el Capítulo 2 revisamos el formalismo teórico detrás de las dualidades gauge/gravedad. Los capítulos 3 y 4 se refieren a las características teóricas y fenomenológicas relevantes de la QCD. En el Capítulo 5 presentamos modelos simples de AdS/QCD y delineamos el análisis holográfico de los espectros de partículas. El Capítulo 6 contiene nuestros resultados originales sobre la determinación de la temperatura de desconfinación de QCD en el marco de AdS/QCD. El Capítulo 7 corresponde al artículo dedicado al estudio de la física de QCD de baja energía desencadenada por la implementación particular de la ruptura de simetría quiral en el modelo con la pared blanda. En el Capítulo 8 se presenta un trabajo sobre Higgs compuesto holográfico. Comenzamos en el Capítulo 2 con una descripción del formalismo central, el de la correspondencia AdS / CFT. Las prescripciones holográficas generales se recopilan en el diccionario AdS / CFT. Luego, especificamos al caso la dualidad de Maldacena entre la teoría de cuerdas tipo IIB en $ AdS_5 \ times S_5 $ espacio-tiempo y la teoría supersimétrica $N=4$ de Yang-Mills en cuatro dimensiones. Discutimos en qué sentido la parte gauge de esta dualidad es similar a large- $ N_c $ QCD y qué aspectos faltan. En el Capítulo 3 discutimos algunos temas seleccionados de QCD. Revisamos varios métodos bien establecidos que permiten estudiar la QCD en diferentes regímenes: a gran número de colores, a pequeñas energías, centrándonos en las implicaciones de la simetría quiral y a temperatura finita. También cubrimos la expansión de productos del operador, la formulación lattice de QCD, sus predicciones e implicaciones. Los observables fenomenológicos de hadrones se consideran en el Capítulo 4 e incluyen los espectros de masas de resonancia, los acoplamientos y los factores de forma. Investigamos en detalle la idea de excitaciones de mesones radiales que pertenecen a las trayectorias radiales lineales de Regge, y enfatizamos la noción de trayectorias de mesones radiales universales. También se analizan los espectros de glueballs, estudiados sobre lattice. Habiendo resaltado las características fenomenológicas relevantes de QCD, pasamos a su implementación holográfica bottom-up. El formalismo general de incluir resonancias QCD en el volumen 5D se presenta en el Capítulo 5. Presentamos varios modelos simples de AdS/QCD: pared dura, pared blanda y pared blanda generalizada. Se evalúan sobre la base de su éxito en la descripción de los espectros fenomenológicos. Los modelos de paredes blandas demuestran la linealidad de las trayectorias radiales esperadas en las teorías con la realización adecuada del confinamiento. Además, mencionamos la posibilidad de adquirir familias de perfiles de paredes blandas que conduzcan a los mismos espectros. En AdS / QCD se asume que la transición de la fase de desconfinamiento es dual a la transición Hawking-Page entre diferentes geometrías en la teoría 5D. Eso nos permite estimar la temperatura (pseudo) crítica de desconfinamiento, $T_c$. En el Capítulo 6 exploramos varios modelos holográficos con diferentes opciones para fijar sus parámetros con el fin de obtener el valor fenomenológico de $T_c$. Los resultados dependen bastante de la elección de los parámetros del modelo. Concluimos que hay un subconjunto que proporciona $T_c$ cerca de las estimaciones de quenched lattice y grande-$ N_c $, y aquellas que predicen $ T_c $ en el rango físico (temperatura de freeze-out, estimaciones lattice con quarks dinámicos). El mecanismo holográfico AdS / QCD para la implementación dual de la ruptura de la simetría quiral se desarrolla en el Capítulo 7. Elegimos el marco de pared blanda e introducimos varias características novedosas para acomodar mejor los modos Goldstone. El modelo resultante no tiene muchos parámetros libres y debido a este minimalismo proporciona interesantes interrelaciones entre diferentes sectores. Se extraen varios observables de interés. El resultado fenomenológico se da en términos del ajuste a quince QCD observables con el error cuadrático medio de $ ~ 30%$. En el Capítulo 8 comenzamos con la motivación para la extensión de BSM con el sector fuertemente acoplado y enfatizamos las ventajas de los modelos CH. Además, nos especializamos en el caso de CH mínimo con el patrón de ruptura de la nueva simetría de sabor tipo $SO (5) -> SO (4) $. Allí aplicamos la técnica AdS / QCD y, en concreto, utilizamos la experiencia del capítulo anterior. Sin embargo, las diferencias con el caso QCD no son tan simples como el intercambio de los grupos de "sabor" y "color". La reconsideración de la realización holográfica y el papel de los bosones de Goldstone es un desarrollo importante del capítulo. Calculamos las masas de las nuevas resonancias compuestas, estimamos varios acoplamientos entre los nuevos estados del sector y los bosones electro-débiles y analizamos la realización holográfica de la primera y segunda reglas de suma de Weinberg. Las limitaciones experimentales de los observables de precisión electro-débil y el ángulo de desalineación, así como el valor conocido de la escala electro-débil, restringen el espacio de parámetros del modelo holográfico y especifican la escala de sus predicciones. Concluimos que el modelo es capaz de acomodar nuevas resonancias vectoriales con masas en el rango de 2-3 TeV sin encontrar dificultades fenomenológicas. En conclusión, aunque los métodos AdS / QCD están lejos de ser precisos, son útiles aunque solo sea para proporcionar un marco bastante simple donde se pueden diseñar y probar diferentes escenarios. Al mismo tiempo, es fundamental tratar conscientemente la cantidad de libertad que otorga este marco fenomenológico. Nos esforzamos por encontrar este equilibrio y elaboramos para motivar bien las suposiciones y elecciones tomadas a lo largo de la construcción del modelo holográfico.
Sondenheimer, René [Verfasser], Holger [Gutachter] Gies, Axel Gutachter] Maas, and Jan M. [Gutachter] [Pawlowski. "Renormalization group flow of the Higgs sector / René Sondenheimer ; Gutachter: Holger Gies, Axel Maas, Jan Pawlowski." Jena : Friedrich-Schiller-Universität Jena, 2016. http://d-nb.info/1177612402/34.
Повний текст джерелаWilhelm, Franz. "Construction of the Higgs Mechanism and the Lee-Quigg-Thacker-bound." Thesis, Uppsala universitet, Högenergifysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388550.
Повний текст джерелаI denna artikel konstrueras higgsmekanismen i standardmodellen stegvis. Först genom att beakta spontant symmetribrott av diskreta samt kontinuerliga globala gaugeinvarianser. Därefter spontant symmetribrott av lokala gaugeinvarianser. Dessa resultat används sedan för att konstruera den elektrosvaga delen av standardmodellen genom tillämpning av higgsmekanismen. Slutligen beräknas en övre gräns för higgsmassan, den så kallade LQT-gränsen, via unitaritetsbegränsingar.
Tarna, Grigore. "Studies of the Higgs boson properties and search for new physics beyond the standard model in the top sector with the ATLAS detector." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0321.
Повний текст джерелаProton-proton collisions at a center of mass energy of 13 TeV recorded during 2015-2017 with the ATLAS detector at LHC are analyzed in this thesis. The first part of the thesis details electron efficiency measurements with a Tag-and-Probe method in Z->ee events. The measured electron reconstruction efficiency varies between 97\% (15Hu or t->Hc) using the 2015-2016 data. These processes are strongly suppressed in the Standard Model (SM), however larger enhancements are predicted in new physics models. Multivariate analyses (MVA) are used to improve signal-background separation in multilepton final states. The measured branching ratio for the t->Hu (t->Hc) process is found to be compatible with zero and a 95\% confidence level upper limit is set at 0.19\% (0.16\%) with an expected limit of 0.15\% (0.15\%), the best limit in a single channel to date.The Higgs boson production in association with a top quark pair (ttH) allows direct access to the top Yukawa coupling. The ttH production mode was observed by the ATLAS and CMS experiments, independently, by combining several decay channels. Further efforts to measure ttH in the two leptons same-sign channel are discussed in the last part of the thesis
Bouchart, Charles. "Phenomenology of the electroweak sector in warped (supersymmetric) extra-dimensional models." Paris 11, 2010. http://www.theses.fr/2010PA112331.
Повний текст джерелаLn the framework of warped extra dimension models addressing the gauge hierarchy problem, we consider the Randall-Sundrum scenario under the usual hypothesis of a bulk custodial symmetry protecting the model from large ElectroWeak corrections together with a Higgs field localized on the so-called TeV-brane. After reviewing the basics of field theory in extra dimensions, we introduce the RS framework, and show in details the construction of our phenomenological model as well as the effects of EW symmetry breaking. We determine the several minimal quark representations allowing to address the anomalies in the forward-backward b-quark asymmetry. It is then shown in details that there can exist large corrections to the Higgs boson Vacuum Expectation Value induced by mixings of the gauge bosons with their KK excitations. The connection with EW precision tests is developed. We find possibly substantial RS corrections to the various Higgs couplings able to affect its phenomenology. The end of this thesis is dedicated to SuperSymmetric extension of warped models, the Higgs field still being confined on the TeV-brane
Capozi, Matteo [Verfasser], and Gerhard [Akademischer Betreuer] Buchalla. "Precision calculations in the Higgs sector within and beyond the Standard Model / Matteo Capozi ; Betreuer: Gerhard Buchalla." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1222436612/34.
Повний текст джерелаWalz, Anne-Kathrin [Verfasser], and M. [Akademischer Betreuer] Mühlleitner. "The Higgs Sector of the (Complex) NMSSM - Higher Order Corrections and Phenomenological Discussions / Anne-Kathrin Walz. Betreuer: M. Mühlleitner." Karlsruhe : KIT-Bibliothek, 2015. http://d-nb.info/1073204855/34.
Повний текст джерелаPruna, Giovanni Marco. "Phenomenology of the minimal B-L Model : the Higgs sector at the Large Hadron Collider and future linear colliders." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/199955/.
Повний текст джерелаKanishchev, Konstantin. "Studies of the Higgs sector in H->ZZ->2l2q and bbH->4b semileptonic channels at CMS." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/368540.
Повний текст джерелаKanishchev, Konstantin. "Studies of the Higgs sector in H->ZZ->2l2q and bbH->4b semileptonic channels at CMS." Doctoral thesis, University of Trento, 2013. http://eprints-phd.biblio.unitn.it/1280/1/Kanishchev_Thesis.pdf.
Повний текст джерелаCottin, Buracchio Giovanna Francesca. "Phenomenology of new physics beyond the Standard Model : signals of supersymmetry with displaced vertices and an extended Higgs sector at colliders." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/265849.
Повний текст джерелаCaspart, René [Verfasser], and R. [Akademischer Betreuer] Wolf. "Confining the Higgs sector via the investigation of di-tau final states with LHC Run II data / René Caspart ; Betreuer: R. Wolf." Karlsruhe : KIT-Bibliothek, 2017. http://d-nb.info/114436776X/34.
Повний текст джерелаMedina, Jaime Miguel 1983. "Interações não padrão de neutrinos no modelo 331 com setor de Higgs mínimo." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278592.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: Neste trabalho apresentamos um estudo de alguns problemas que ainda não forem esclarecidos na física de neutrinos do modelo padrão (MP) e encaminhamos eles na direção de física nova. Para esse fim, estuda-se uma classe de extensões de Gauge quirais do MP com simetria SU(3)C x SU(3)L x U(1)X (modelos 331), onde estudamos a interação eletrofraca dos neutrinos com a matéria via correntes carregadas e neutras (CC e CN) através dos bósons Gauge do modelo para processos de espalhamento elástico coerente. Finalmente, encontramos vínculos entre as contribuições não padrão no modelo 331 com as interações não padrão (INP) em experimentos de seção de choque, onde encontramos que o modelo 331 apresenta INP diagonais universais da ordem e a M2 W,Z / M2 X <~ O(10-3). Mostramos que o valor esperado no vácuo (VEV) para o tão procurado bóson de Higgs neste modelo tem que ser ?2 <~174.105GeV e os VEV V > 1.3TeV e 142 GeV < ?1 < 201GeV. Os novos bósons do modelo deverão ter massas maiores a 610 GeV
Abstract: We present a study of some problems that are not yet clarified in Standard Model (SM) neutrino physics and guide them in the direction of new physics. To this aim, we study a class of extensions of the SM Gauge chiral symmetry SU(3)CSU(3)LU(1)X (331 model), where we study the electroweak interaction of neutrinos with matter via charged and neutral current (CC and NC) by the gauge bosons of the model for coherent elastic scattering process. We finally found connections between the non-standard contributions on 331 with non-standard interactions (NSI) in cross section experiments, where we find that the model 331 has diagonal universal NSI of order e a M2 W,Z / M2 X <~ O(10-3) . We show that the expected value in vacuum (VEV) for the quite searched Higgs boson in this model has to be ?2 <~174.105 GeV and the VEV V > 1.3TeV and 142 GeV < ?1 < 201 GeV. The new bosons of the model must have masses greater than 610 GeV
Mestrado
Física das Particulas Elementares e Campos
Mestre em Física
Alexander-Nunneley, Lisa Pamela. "The minimal scale invariant extension of the standard model." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/the-minimal-scale-invariant-extension-of-the-standard-model(9fdbf3a3-ed27-428a-9b3c-80a3a1b3b9e6).html.
Повний текст джерелаGaller, Peter. "Effects of heavy Higgs bosons in the hadronic production of top-quark pairs including QCD corrections." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/18796.
Повний текст джерелаIn this dissertation a possible extension of the standard model of particle physics (SM) in the Higgs sector is investigated using top-quark pair production at the Large Hadron Collider as a probe. In particular, the so-called two-Higgs-doublet model (2HDM) is studied. The 2HDM introduces several spin-0 bosons (which are also called Higgs bosons) in addition to the SM Higgs boson. In this thesis these additional Higgs bosons are assumed to be heavy enough to decay into a top-antitop quark pair. Thus, the experimental signatures of these new particles can be studied through observables of top-quark pair production. To this end the resonant production of heavy neutral Higgs bosons and their decay into top-quark pairs in calculated up to next-to-leading order corrections in the QCD coupling constant retaining the full spin information of the top-antitop pair. This allows to analyse spin dependent observables which can be more sensitive to effects of heavy Higgs bosons than spin independent ones especially in the case of top-antitop spin correlations. The additional application of kinematical cuts on the phase space of top and antitop quarks can enhance the sensitivity further. In this thesis a method is presented that can be used to construct the spin correlation which is most sensitive to the effects of heavy Higgs bosons on top-quark pair production. Furthermore, it is shown that the next-to-leading order corrections are required to construct observables which entail robust predictions. The results for the next-to-leading order in the QCD coupling constant presented in this thesis were the first ones given for resonant heavy Higgs production and decay into top-quark pairs.
Asmuß, Jan Paul [Verfasser]. "Search for high-mass bosons of an extended Higgs sector in b quark final states using the 2017 data set of the CMS experiment / Jan Paul Asmuß." Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2021. http://nbn-resolving.de/urn:nbn:de:gbv:18-ediss-94102.
Повний текст джерелаAkeroyd, Andrew Gerard. "Signals of non-minimal Higgs sectors at future colliders." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5288/.
Повний текст джерелаBishara, Fady. "Prospecting for New Physics in the Higgs and Flavor Sectors." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439295686.
Повний текст джерелаBertella, Claudia. "Probing top quark and Higgs boson production in multijet events at the LHC with the ATLAS detector." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4055.
Повний текст джерелаProbing top quark and Higgs boson production in multi-jet avents at the LHC with the Atlas detector.The Atlas detector is a general purpose detector located at the Large Hadron Collider (LHC). It aims at the discovery af new physics phenomena and improving our knowledge of the standart Model (SM)
Ziesche, Hanna [Verfasser], and M. [Akademischer Betreuer] Mühlleitner. "Higher-Order Corrections in Extended Higgs Sectors / Hanna Ziesche ; Betreuer: M. Mühlleitner." Karlsruhe : KIT-Bibliothek, 2016. http://d-nb.info/1119242932/34.
Повний текст джерелаAbreu, Aguilar Henso Javier. "Measurement of the inclusive prompt photon cross section and preparation of the search of the Higgs boson decaying into two photons with the ATLAS detector at the LHC." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00627369.
Повний текст джерелаSchwoerer, Maud. "'Etudes des états finals diphoton dans l'expérience ATLAS au LHC : mesure de section efficace différentielle, découverte d'une nouvelle résonance dans la recherche du boson de Higgs et étude de ses propriétés'." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00978539.
Повний текст джерелаLi, H. "Higgs Recoil Mass and Cross-Section Analysis at ILC AND Calibration of the CALICE SiW ECAL Prototype." Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00430432.
Повний текст джерелаBernon, Jérémy. "Caractérisation du secteur de Higgs et aspects du problème de la saveur." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY020/document.
Повний текст джерелаThe Standard Model (SM) of particle physics stands as the most successful description of the fundamental interactions between elementary particles. The discovery of a Higgs boson, at a mass of 125 GeV, in July 2012 at the Large Hadron Collider (LHC), marked its ultimate confirmation. However, various observational and theoretical problems lie in the heart of the SM, with the majority of them linked to the Higgs sector. Being a scalar, the Higgs boson is subject to very large radiative corrections and this ultimately leads to the electroweak hierarchy problem. One of the main goals of the LHC program is to precisely probe the Higgs sector, in order to characterize the mechanism at the origin of the breaking of the electroweak symmetry and test possible solutions to the hierarchy problem. The Higgs sector is also responsible for the generation of the fermion masses, as it induces the Yukawa couplings. The SM flavor sector is highly hierarchical and this leads to flavor puzzles in theories beyond the SM.The first part of this thesis is dedicated to the precise characterization of the Higgs sector. In particular, the public tool Lilith is presented, which allows to derive constraints on new physics models based on the Higgs measurements at colliders. It is then used to perform global fits of the Higgs couplings in the context of various scenarios. In the second part, the phenomenology of two-Higgs-doublet models is studied in the light of the results from the first run of the LHC. The so-called alignment limit is explored in detail, as well as the possible presence of light scalar states. Finally, in the last part of this thesis, the Minimal Flavor Violation hypothesis is introduced as a possible solution to the flavor puzzles beyond the SM. Enforcing it in the Minimal Supersymmetric Standard Model, the renormalisation group evolution of the baryonic R-parity violating couplings is then studied in detail
Helmboldt, Alexander [Verfasser], and Manfred [Akademischer Betreuer] Lindner. "New insights into modified scalar sectors and exotic Higgs decays / Alexander Helmboldt ; Betreuer: Manfred Lindner." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177253364/34.
Повний текст джерелаLesage, Arthur Alexis Jules. "Study of the fiducial cross section of the Higgs boson decaying into four leptons and study of muon isolation in the ATLAS experiment at the LHC." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS208/document.
Повний текст джерелаThe main subject of the thesis is the measurement of the production cross section of the Higgs boson decaying to two Z bosons in the four-lepton final state (H →ZZ * → 4l, l = e, μ), using 36.1 fb- 1 of data recorded during 2015 and 2016 with the ATLAS experiment installed at the Large Hadron Collider (LHC) at CERN. The inclusive fiducial cross section in the H → ZZ * → 4l decay channel is measured to be 3.62 ± 0.53 (stat) ± 0.25 (syst) fb,in agreement with the Standard Model prediction of 2.91 ± 0.13 fb. Several differential fiducial cross sections are measured for observables sensitive to the Higgs-boson production and decay, including kinematic distributions of the jets produced together with the Higgs boson. Good agreement is found between the data and the predictions of the Standard Model. The extracted cross-section distributions are also used to constrain anomalous Higgs-boson interactions with Standard-Model particles.The second part of the thesis is dedicated to the muon isolation. Isolation variables, based on information from the tracker (track-based isolation) and the calorimeters (calorimeter-based isolation) measure the ambient activity surrounding a particle in the detectors and are a powerful tool to reject background objects. Using36.1 fb-1 of data recorded by ATLAS in 2015 and2016, the variable distributions are compared with simulation. Working points are then defined as sets of cuts applied to the isolation variables. Using theZ boson decays to a pair of muons, the signal efficiency of the working points is calculated. Scale factors are then derived as ratio of efficiencies measured in data over simulation. The good agreement leads to scale factors close to one
Fowler, Alison Clare. "Higher order and CP-violating effects in the neutralino and Higgs boson sectors of the MSSM." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/449/.
Повний текст джерелаBarnovska, Zuzana. "Diphoton measurements with the ATLAS detector at LHC : search for new resonances and study of diphoton production in association with jets." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY072/document.
Повний текст джерелаThis thesis studies pp collisions at sqrt{s}=8 TeV with pairs of photons in the final state, as collected by the ATLAS experiment at the LHC during 2012. The diphoton final state has proven to be crucial to the discovery of the Higgs boson. The motivation for searching for additional resonances decaying into two photons is very strong due to many models predicting an extended Higgs sector. At the same time, detailed measurements of diphoton cross sections are necessary to establish the quality of the theoretical predictions currently available for these processes.The measurement of photons by ATLAS relies on an excellent calibration of the electromagnetic calorimeter response. For this reason, studies related to the calibration of the photon response in the ATLAS Liquid Argon (LAr) calorimeter are initially performed, including a measurement of the calorimeter layer energy scale relative calibration using photons, and the potential need of an inter-calibration of the photon energy response as a function of the azimuthal angle $phi$. A study of noise performance of the calorimeter in high pile-up conditions is also presented, resulting in recommendations for the LAr pulse sampling configurations for Run2.A search for an additional resonance decaying into two photons is performed, leading to no significant excess being observed. A limit on the fiducial cross section times branching fraction of a new resonance decaying into two photons is therefore computed. The measurement of the production cross section of isolated prompt diphoton in association with jets is performed as a function of the diphoton invariant mass, the transverse momentum of the diphoton system, the azimuthal angle difference of the two photons and the coplanarity angle theta, for jet multiplicity categories and as a function of various jet variables. The results are compared to the latest Next-To-Leading-Order QCD predictions. Such a measurement has not been previously published at the LHC
Machet, Martina. "Higgs boson production in the diphoton decay channel with CMS at the LHC : first measurement of the inclusive cross section in 13 TeV pp collisions, and study of the Higgs coupling to electroweak vector bosons." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS254/document.
Повний текст джерелаIn this document two analyses of the properties of the Higgs boson in the diphoton decay channel with the CMS experiment at the LHC (Large Hadron Collider) are presented.The document starts with a theoretical introduction of the Standard Model and the Higgs boson physics, followed by a detailed description of the CMS detector.Then, photon reconstruction and identification algorithms are presented, with a particular focus on the differences between the first and the second run of the LHC, the first run (Run1) took place from 2010 to 2012 with a centre-of-mass energy of 7 and then 8 TeV, while the second run (Run2) started in 2015 with a centre-of-mass energy of 13 TeV. Performances of Run1 and Run2 reconstructions from the photon identification point of view are compared. Then the photon identification algorithm for the H->γγ analysis optimised for Run2 is presented. To do that a multivariate analysis method is used. Performances of the photon identification at 13 TeV are finally studied and a data-simulation validation is performed.Afterwards, the H->γγ analysis using the first Run2 data is presented. The analysis is performed with a dataset corresponding to an integrated luminosity of 2.7/fb. An event classification is performed to maximize signal significance and to studyspecific Higgs boson production modes. The observed significance for the standard model Higgs boson is 1.7 sigma, while a significance of 2.7 sigma is expected.Finally a feasibility study, having the aim of constraining the anomalous couplings of the Higgs boson to the vector bosons, is presented. This analysis is performed using the data collected at 8 TeV during Run1 at the LHC, corresponding to an integrated luminosity of 19.5/fb. This analysis exploits the production of the Higgs boson through vector boson fusion (VBF), with the Higgs decaying to 2 photons. The kinematic distributions of the dijet and diphoton systems, which depend from the spin-parity hypothesis, are used to build some discriminants able to discriminate between different spin-parity hypotheses. These discriminants allow to define different regions of the phase-space enriched with a certain spin-parity process. The Higgs boson signal yield is extracted in each region from a fit to the diphoton mass, allowing to determine the contributions of the different processes and then constrain the production of a pseudo-scalar (spin-parity 0-) Higgs boson
HIRN, Johannes. "Formulation de la théorie effective à basse énergie du secteur électrofaible sans particule de Higgs." Phd thesis, Université Paris Sud - Paris XI, 2004. http://tel.archives-ouvertes.fr/tel-00008357.
Повний текст джерелаSU(2)xU(1) via des spurions. Les opérateurs indésirables n'apparaissent qu'aux ordres supérieurs du développement simultané en puissances des impulsions et des spurions. De plus, la brisure de l'isospin faible est traitée de façon systématique et la formule de comptage de Weinberg peut être reproduite. Les spurions permettent de rendre compte des faibles masses des neutrinos actifs. Les trois neutrinos droits, légers par rapport au TeV, introduits afin de préserver une symétrie custodiale, sont quasi-stériles et stables. On étudie également le raccordement des anomalies dans le secteur composite, généralisant la construction de Wess-Zumino: on obtient une contrainte sur la théorie sous-jacente. Appliquant le formalisme des spurions aux modèles "moose" linéaires ouverts, on démontre des règles de somme de Weinberg généralisées.
Hirn, Johannes. "Formulation de la théorie effective à basse énergie du secteur électrofaible sans particule de Higgs." Paris 11, 2004. https://tel.archives-ouvertes.fr/tel-00008357.
Повний текст джерелаThe low-energy effective theory of electroweak symmetry-breaking without a Higgs particle is constructed using the methods of Chiral Perturbation Theory. Weinberg's power-counting formula demonstrates the consistency of the loop expansion, with the corresponding renormalization. We find that the suppression of effective operators by a mass scale, which was automatic in the case of the Standard Model, no longer holds in the Higgs-less case for a specific class of operators. Moreover, the incriminated operators appear at leading order in the chiral expansion, in conflict with experiments. To account for their suppression, invariance under a larger symmetry is required, corresponding to the composite sector (which produces the three Goldstone modes) being decoupled from the elementary sector (quarks, leptons and Yang-Mills fields). The couplings are introduced via spurions: this reduces the symmetry to SU(2)xU(1). Ln the simultaneous expansion in powers of momenta and spurions, the aforementioned operators are relegated to higher orders. Ln addition, the method allows for a systematic treatment of weak isospin breaking. The Weinberg power-counting formula can be recovered, and small neutrino masses accounted for. The three right-handed neutrinos (lighter than the TeV) are introduced in connection with the custodial symmetry: they are quasi-sterile and stable and may thus contribute to dark matter. We also obtain a constraint on the underlying theory by studying the anomaly-matching in the composite sector and generalizing the Wess-Zumino construction. The spurion formalism is also applied to open linear moose models, for which generalized Weinberg sum rules are derived
Wooden, Gemma H. "A search for H -> WW using a matrix element discriminant and a WW cross section measurement at ATLAS." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:d75dcc58-063d-48ec-9ea9-e5c2e60ec9c9.
Повний текст джерелаGlaysher, Paul Christopher Frederick. "Differential cross section measurements in H→ WW and prospects of observing H→ bb in future LHC runs at the ATLAS detector." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22074.
Повний текст джерелаBall, Gordon. "Cross section studies of the Z and neutral supersymmetric Higgs bosons decaying to tau leptons at CMS." Thesis, Imperial College London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544292.
Повний текст джерелаLarner, Aimee Bridget. "Measurement of the Z—>TlTh cross-section and search for the standard model vector boson fusion produced Higgs —>TlTh at ATLAS." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:1b7174f0-802f-40ac-9ae9-bc0c589e4d6e.
Повний текст джерелаAndrea, Jérémy Bloch Daniel. "Mesure de la section efficace de production de paires de quarks top dans l'expérience CMS au LHC." Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/1127/01/ANDREA_Jeremy_2009_restrict.pdf.
Повний текст джерелаKonrath, Jens-Peter. "Measurement of the top quark pair production cross-section in dimuon final states in proton-antiproton collisions at 1.96 TeV." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-59358.
Повний текст джерелаMillischer, Laurent. "Mesure de la section efficace de production de paires de photons isolés avec le détecteurs CMS." Paris 7, 2011. http://www.theses.fr/2011PA077209.
Повний текст джерелаThe predictions made by the Standard Model of particle physics have been tested experimentally to a considerable degree of precision. The quest is now on, at high energy particle colliders, for the only remaining pièce within the framework of the Standard Model to be discovered, namely the Higgs boson, which is responsible for the electroweak symmetry breaking. The asymptotic freedom of Quantum Chromodynamics (QCD), the theory of strong interactions in the Standard Model, makes QCD predictions possible in perturbation theory. The comparatively high value of the strong coupling constant however makes several orders of the series necessary for predictions to be accurate and comparable to measurements. The mass of the Higgs boson is known from direct searches and by precision fits of electroweak data. In the lower part of this mass window, searches of the Higgs boson decaying to two photons are among the most sensitive. Studies of isolated photon pairs at the LHC allow the testing QCD in its perturbative regime at energy scales never probed before. Moreover, the measurement of the cross section of diphotons is crucial, as photon pairs produced in hard QCD interactions form the largest irreducible background to the search for a low mass Higgs boson that decays to diphotons. This thesis presents a comprehensive study of the production cross section of pairs of prompt isolated photons. Its last chapter gives the details of the first measurement of the production cross section of pairs of isolated photons with the CMS detector at a centre-of-mass energy of 7 TeV
Follega, Francesco Maria. "Search for boosted Higgs bosons decaying to b-quarks at sqrt{s}=13 TeV with the ATLAS detector." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259651.
Повний текст джерелаFollega, Francesco Maria. "Search for boosted Higgs bosons decaying to b-quarks at sqrt{s}=13 TeV with the ATLAS detector." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259651.
Повний текст джерелаQin, Yang. "Search for tt̄H production and measurement of the tt̄ cross-section with the ATLAS detector." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/search-for-tbarth-production-and-measurement-of-the-tbart-crosssection-with-the-atlas-detector(1c05f62c-67ad-4011-802d-703d045490f1).html.
Повний текст джерелаMURRONE, ALESSIA. "MEASUREMENTS OF THE HIGGS BOSON PRODUCTION CROSS SECTION AND OF CP VIOLATION IN THE DITAU DECAY CHANNEL WITH THE ATLAS DETECTOR." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/785300.
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