Literatura académica sobre el tema "Electroweak fit"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros

Elija tipo de fuente:

Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Electroweak fit".

Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.

También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.

Artículos de revistas sobre el tema "Electroweak fit"

1

Ciuchini, M., E. Franco, S. Mishima y L. Silvestrini. "Electroweak theory and global fit". EPJ Web of Conferences 60 (2013): 08004. http://dx.doi.org/10.1051/epjconf/20136008004.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
2

Quast, Günter. "Global fit to electroweak precision data". European Physical Journal C 33, S1 (3 de febrero de 2004): s641—s643. http://dx.doi.org/10.1140/epjcd/s2004-03-1611-4.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
3

Zhang, Ying, Shao-Zhou Jiang y Qing Wang. "Global Electroweak Fit and Its Implication for Z ′". Communications in Theoretical Physics 61, n.º 6 (junio de 2014): 729–34. http://dx.doi.org/10.1088/0253-6102/61/6/11.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
4

Gurtu, Atul. "Precision Tests of the Electroweak Theory". International Journal of Modern Physics A 18, n.º 21 (20 de agosto de 2003): 3591–627. http://dx.doi.org/10.1142/s0217751x03013958.

Texto completo
Resumen
Electroweak data from the high energy electron–positron and proton–antiproton colliders are reviewed. On the whole the data is consistent with and supports the predictions of the electroweak theory. However, a crucial prediction of the theory remains to be verified: the existence of the Higgs boson and its light mass, less than 193 GeV, obtained from a fit to all the data within the electroweak framework. The lower limit on its mass from direct searches being 114 GeV, the mass of the Higgs is fixed within a narrow range which is expected to be explored at the Fermilab Tevatron experiments or later at the Large Hadron Collider at CERN.
Los estilos APA, Harvard, Vancouver, ISO, etc.
5

Kvedaraitė, Sandra. "Two-loop Electroweak Corrections to ϵK". Journal of Physics: Conference Series 2446, n.º 1 (1 de febrero de 2023): 012020. http://dx.doi.org/10.1088/1742-6596/2446/1/012020.

Texto completo
Resumen
Abstract The parameter εK measures CP violation in the neutral kaon system. It is a sensitive probe of new physics and plays a prominent role in the global fit of the Cabibbo-Kobabyashi-Maskawa matrix. As one of the first discovered sources of CP violation, it has been measured in experiment to permil precision. A simple reparametrization of the efFective Hamiltonian has been recently shown to drastically reduce the perturbative errors coming from the charm-quark corrections, making the electroweak corrections relevant. In this proceedings, I will present the two-loop electroweak corrections to ϵK .
Los estilos APA, Harvard, Vancouver, ISO, etc.
6

HIOKI, ZENRŌ. "TOP AND HIGGS HUNTING VIA Mw AND Γz". Modern Physics Letters A 06, n.º 23 (30 de julio de 1991): 2129–35. http://dx.doi.org/10.1142/s0217732391002311.

Texto completo
Resumen
Virtual top and Higgs effects are studied through the electroweak radiative corrections to the W boson mass, MW, and the total decay-width of the Z boson, ΓZ, by using the data [Formula: see text], [Formula: see text] and [Formula: see text]. Carrying out the χ2 fit in the framework of the standard electroweak theory, constraints are derived on the top-quark mass, mt, and the Higgs–boson mass, mϕ, which are almost free from the complicated hadron physics like parton model calculations. For example, [Formula: see text] for mϕ = 100 GeV (at 1σ level) while mϕ ≲ 680 GeV if mt ≤ 110 GeV and mϕ ≳ 280 GeV if mt ≥ 190 GeV . It is also studied how precise measurements of MW at LEP II improve these constraints.
Los estilos APA, Harvard, Vancouver, ISO, etc.
7

CHO, GI-CHOL. "LOOKING FOR Z′ BOSONS IN SUPERSYMMETRIC E6 Models THROUGH ELECTROWEAK PRECISION DATA". Modern Physics Letters A 15, n.º 05 (20 de febrero de 2000): 311–31. http://dx.doi.org/10.1142/s021773230000030x.

Texto completo
Resumen
We review constraints on additional Z′ bosons predicted in supersymmetric (SUSY) E6 models from electroweak experiments — Z-pole experiments, mW measurements and the low-energy neutral current (LENC) experiments. Four representative models — χ, ψ, η and ν — are studied in some detail. We find that the improved data of parity violation in cesium atom, which is 2.2-σ away from the standard model (SM) prediction, could be explained by the exchange of the heavy mass eigenstate Z2 in the intermediate state. The improvement over the SM can be found in χ, η, ν models, where the total χ2 of the fit to the 26 data points decreases by about five units, owing to the better fit to the atomic parity violation. Impacts of the kinetic mixing between the U (1)Y and U (1)′ gauge bosons on the χ2-analysis are studied. We find that the Z′ model with (βE,δ)=(-π/4,0.2), where βE is the mixing angle between Zχ and Zψ bosons and δ denotes the kinetic mixing, shows the most excellent fit to the data: The total χ2 decreases by about seven units as compared to the SM. We introduce the effective mixing parameter ζ, a combination of the mass and the kinetic mixing parameters. The 95% CL lower mass bound of Z2 can be shown as a function of ζ. A theoretical prediction on ζ and the U (1)′ gauge coupling gE is studied for the χ, ψ, η and ν models by assuming the minimal particle content of the SUSY E6 models.
Los estilos APA, Harvard, Vancouver, ISO, etc.
8

ELLIS, JOHN. "SUMMARY OF ICHEP 2004". International Journal of Modern Physics A 20, n.º 22 (10 de septiembre de 2005): 5297–315. http://dx.doi.org/10.1142/s0217751x05028806.

Texto completo
Resumen
Aspects of ICHEP 2004 are summarized from a theoretical point of view. QCD works, new NNLO calculations are becoming available and new string calculational tools are emerging, but no conclusions can yet be drawn about the discovery of the quark-gluon plasma or pentaquarks. The small upward shift in the experimental value of mt raises somewhat the central value of the Higgs mass extracted from a global electroweak fit, and the CKM model describes well the data from the B factories. The Super-Kamiokande, KamLAND and K2K experiments have evidence for oscillation dips in their neutrino data. Little Higgs models are interesting alternatives to low-energy supersymmetry for stabilizing the electroweak scale. Convincing experimental evidence for dark matter particles is still lacking. The LHC is on its way, the technology choice clarifies the roadmap for the ILC, and a multi-TeV CLIC would also have rich physics agenda.
Los estilos APA, Harvard, Vancouver, ISO, etc.
9

KONG, DERRICK. "NEW R VALUES FROM 2-5 GEV FROM THE BESII AT BEPC". International Journal of Modern Physics A 16, supp01a (octubre de 2001): 281–83. http://dx.doi.org/10.1142/s0217751x01006693.

Texto completo
Resumen
We report preliminary R values for all 85 energy points scanned in the energy region of 2-5 GeV with the upgraded Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC). The typical uncertainties on the R values we measured are ~ 7%. The new R values have a significant impact on the predicted mass of the Higgs (mH) coming from the global fit to the electroweak data, and will also contribute to the interpretation of the E821 g - 2 experiment.
Los estilos APA, Harvard, Vancouver, ISO, etc.
10

Flächer, H., M. Goebel, J. Haller, A. Hoecker, K. Mönig y J. Stelzer. "Revisiting the global electroweak fit of the Standard Model and beyond with Gfitter". European Physical Journal C 60, n.º 4 (19 de marzo de 2009): 543–83. http://dx.doi.org/10.1140/epjc/s10052-009-0966-6.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "Electroweak fit"

1

Pinto, Pinoargote Andres. "Measurement of the W-Boson Mass with the ATLAS Detector at the LHC". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP057.

Texto completo
Resumen
Le présent travail montre l'état actuel de la mesure de la masse du boson W en utilisant les données du LHC en collisions proton-proton collectées par le détecteur ATLAS à 5.02, 7 et 13 TeV. Pour ce faire, des procédures de calibration dédiées du Détecteur Interne (DI) et du Spectromètre à Muons (SM) d'ATLAS ont été conçues et appliquées, et la stratégie de la mesure a été optimisée.La procédure de calibration du DI prend en compte les biais possibles dans la flèche de la trace du muon, les déformations géométriques et les distorsions du champ magnétique. Dans le cas du SM, les résidus d'alignement entre le DI et le SM ont été étudiés, et le champ magnétique toroïdal résiduel présent dans les calorimètres a été réévalué. Une calibration dédiée de l'impulsion du muon a été mise en œuvre. Après ces corrections, l'accord entre les données et la simulation est trouvé au niveau du pour mille, et les incertitudes correspondantes sont propagées à la mesure de la masse du boson W.Le présent travail comprend également une étude détaillée de la stratégie d'ajustement de la masse du boson W. Un ajustement de type profil de vraisemblance (profile likelihood) analytique dans la limite gaussienne a été mis en œuvre, permettant une décomposition adéquate des incertitudes de l'ajustement, améliorant les “impacts” habituels. Dans ce scénario, nous sommes en mesure de déterminer la contribution réelle de chaque source systématique à l'incertitude finale de la mesure. Les données de mesure résultantes peuvent alors être utilisées de manière cohérente pour d'autres combinaisons et ajustements.L'ajustement analytique a été utilisé pour obtenir une mesure de la masse du boson W à 7 TeV avec une valeur de 80366.5 ± 15.9 MeV, en bon accord avec les ajustements numériques. Pour l'ensemble de données à faible empilement (low pile-up), la calibration améliorée et la stratégie d'ajustement optimisée aboutissent à une précision attendue de 14.3 MeV. En combinant avec les données à 7 TeV, une précision finale de 10.3 MeV est attendue.La compatibilité et la combinaison des mesures de la masse du boson W avec la nouvelle mesure ATLAS 2024 à 7 TeV et d'autres mesures (LEP, CDF, D0, LHCb) ont été étudiées. La combinaison donne m_W = 80388.4 ± 10.3 MeV avec 0.2% de compatibilité en incluant CDF, et m_W= 80366.1 ± 11.7 MeV avec 92% sans CDF, différant du résultat CDF par 3.8σ
The present work shows the current status of the determination of the W boson mass, using the LHC datasets in proton-proton collisions collected by the ATLAS detector at 5.02, 7 and 13 TeV. To achieve this, dedicated calibration procedures of the ATLAS Inner Detector (ID) and Muon Spectrometer (MS) have been designed and applied, and the W boson mass measurement strategy has been optimised.The ID calibration procedure considers possible biases in the muon track sagitta, geometrical deformations and magnetic field distortions. In the case of the MS, the alignment residuals between the ID and MS have been investigated, and the residual toroidal magnetic field present in the calorimeters has been re-evaluated. A dedicated muon momentum calibration has been implemented. After these corrections, the data-to-simulation agreement is found to be at the per mille level, and the corresponding uncertainties are propagated to the W-boson mass measurement.The present work also includes a detailed study of the W-boson mass fitting strategy. An analytical Profile Likelihood fit in the Gaussian limit has been implemented, allowing a proper decomposition of the fit uncertainties, improving over the usual “impacts”. In this scenario, the actual contribution of each systematic source to the final measurement uncertainty can be determined. The resulting measurement data can then be used consistently for further combinations and fits.The analytical fit was used to obtain a W mass measurement at 7 TeV with value 80366.5 ± 15.9 MeV, in good agreement with numerical fits. For the low pile-up dataset, the improved calibration and optimised fitting strategy result in an expected precision of 14.3 MeV. Combining with the 7 TeV data an ultimate precision of 10.3 MeV can be obtained.The compatibility and combination of the world W-boson mass using the new ATLAS 2024 measurement at 7 TeV with other measurements (LEP, CDF, D0, LHCb) was studied. The combination yields m_W = 80388.4 ± 10.3 MeV with 0.2% compatibility when CDF is included, and m_W = 80366.1 ± 11.7 MeV with 92% compatibility when CDF is removed, differing from the CDF result by 3.8σ
Los estilos APA, Harvard, Vancouver, ISO, etc.
2

Tonero, Alberto. "Asymptotic safety and the electroweak interactions". Doctoral thesis, SISSA, 2012. http://hdl.handle.net/20.500.11767/4688.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
3

Menzel, Andreas. "Constraints on the Fourth-Generation Quark Mixing Matrix from Precision Flavour Observables". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17711.

Texto completo
Resumen
Das Standardmodell einer zusätzlichen sequentiellen Fermiongeneration (SM4) war 2012 auf Basis eines Fits an elektroschwache Präzisionsobservable und die Higgs-Signalstärken mit einer Signifikanz von 5.3 sigma ausgeschlossen worden. Komplementär dazu wurden in der vorliegenden Arbeit Fits des SM4 an eine Kombination eines typischen Satzes von Flavour-Observablen mit den Ergebnissen des zuvor durchgeführten Elektroschwachen Präzisionsfits durchgeführt. Im SM3-Kontext extrahierte Größen wurden gemäß ihrer Bedeutung im SM4 reinterpretiert und die angepassten theoretischen Ausdrücke angegeben. Die resultierenden Einschränkungen der CKM-Matrix des SM4, ihrer potentiell CP-verletzenden Phasen sowie der Masse des up-type-Quarks der 4. Generation t'' werden angegeben. Zum Vergleich des SM4 mit dem SM3 werden die erreichten chi^2-Werte genutzt. chi^2=15.53 im SM4 und 9.56 im SM3 passen fast vollkommen zu einer gleich guten Beschreibung der Experimente durch beide Modelle, wobei das SM3 aber sechs Freiheitsgrade mehr besitzt. Außerdem wurden die Vorhersagen des SM3 und des SM4 für die Dimyon-Ladungsasymmetrie ASL mit experimentellen Werten verglichen. Die Vorhersage des SM3 ist ca. 2 sigma vom experimentellen Wert entfernt, die des SM4 ca. 3 sigma.\par Die Ergebnisse deuten nicht darauf hin, dass die Signifikanz des 2012 erreichten Ausschlusses des SM4 durch die Hinzunahme von Flavour-Observablen zu den damals verwendeten elektroschwachen Präzisionsobservablen und Higgs-Querschnitten bedeutend verringert würde.\par Es konnte jedoch keine genaue quantitative Aussage über die Auswirkungen der Flavourobservablen auf diese Signifikanz getroffen werden, weil das Programm CKMfitter likelihood-ratio-Berechnung nur durchführen kann, wenn sich eines der untersuchten Modelle durch Fixierung von Parametern aus dem anderen ergibt (nested models), was hier nicht der Fall ist.
The Standard Model extended by an additional sequential generation of Dirac fermions (SM4) was excluded with a significance of 5.3 sigma in 2012. This was achieved in a combined fit of the SM4 to Electroweak Precision Observables and signal strengths of the Higgs boson. This thesis complements this excludion by a fit of the SM4 to a typical set of Flavour physics observables and the results of the previously performed Electroweak Precision fit. Quantities extracted in an SM3 framework are reinterpreted in SM4 terms and the adapted theoretical expressions are given. The resultant constraints on the SM4''s CKM matrix, its potentially CP-violating phases and the mass of the new up-type quark t'' are given. To compare the relative performance of the SM4 and the SM3, this work uses the chi^2 values achieved in the fit. The values of 15.53 for the SM4 and 9.56 for the SM4 are almost perfectly consistent with both models describing the experimental data equally well with the SM3 having six degrees of freedom more. The dimuon charge asymmetry ASL was not used as a fit input because the interpretation of its measurement was subject to debate at the time when the fits were produced, but its prediction in the fit was used as an additional test of the SM4. The SM3''s prediction differs from the experimental values by about 2 sigma, and the SM4''s prediction by about 3 sigma. \par In summary, these results do not suggest that any significant reduction of the 5.3 sigma exclusion could be achieved by combining the Electroweak Precision Observables and Higgs inputs with Flavour physics data. However, the exact effect of the Flavour physics input on the significance of the SM4''s exclusion cannot be given at this point because the CKMfitter software is currently not able to perform a statistically stringent likelihood comparison of non-nested models.
Los estilos APA, Harvard, Vancouver, ISO, etc.
4

IACOBELLIS, Giuseppe. "Higgs connections: Electroweak Vacuum Stability and Cosmology". Doctoral thesis, Università degli studi di Ferrara, 2017. http://hdl.handle.net/11392/2487829.

Texto completo
Resumen
The discovery of the Higgs boson at LHC and the determination of its mass value have opened up the possibility to study the Standard Model (SM) up to very high energies, in order to probe the consistency of the theory and its range of validity, considering the model as an effective one. In this framework, equipped with the latest experimental data, a lot of interest has been devoted to the study of the stability of the SM electroweak vacuum and the peculiar implications both in particle physics and, mostly, in cosmology. Our work fits in this scenario with a two-fold aim: on one side, we try to refine the latest calculations of the stability bounds, in the light of the updated experimental data and the new theoretical approaches in the improved effective potential technique; while, on the other side, we take advantage of this analysis in order to investigate and constrain some realisation of the primordial inflationary phase within the pure SM and its some minimal extensions. In particular, we studied the gauge-independent observables related to two interesting stationary configurations of the SM potential, extrapolated up to high energies by means of the state-of-the-art RGE-improved effective potential approach, namely the Next-to-Next-to-Leading Order: the value of the top quark mass which ensures the electroweak vacuum stability (criticality) and the potential evaluated at the inflection point. Proved the gauge independence of these observables, there were estimated in detail the uncertainties related. The first main result, in agreement with the well-known literature (with some minor discrepancies), is that the SM absolute stability is not completely excluded, given the current experimental data: it is possible to assume the theory valid up to the Planck scale, at which we suppose that the gravitational interaction starts to be relevant, without any inclusion of new physics at low energy ("desert scenario"). Starting from this point, we tried to explain the inflationary phase embedded in a pure SM scenario, exploiting the inflection point configuration. However, we showed that it turns out to be impossible to reproduce the most recent bounds on the primordial tensor-to-scalar-ratio in the sight of SM inflection point models. Being necessary the introduction of new degrees of freedom, in order to include a reasonable inflationary expansion and, consistently, the stabilisation of the SM potential, we try to review the main features of a minimal extension of the SM, through a global U(1)_{B-L} symmetry and try to constrain its parameters so as to achieve both our goals. The extra scalar singlet associated with the breaking of this new symmetry, granting the stabilisation through an induced tree-level threshold effect, would be responsible of the generation of the right-handed neutrino mass, which in turn would provide, via the type I see-saw mechanism, the masses of the low-energy neutrinos. In this framework, we found the parameter window attainable for both a successfully inflationary phase, driven by the same heavy scalar, and the stabilisation of the model: we confirm the results reported in the literature, although the related works carry out the analysis in slightly different setups and often comparing the results to different experimental bounds, leading to different conclusions. However, the overall outcome is perfectly compatible: sticking with the current experimental state-of-the-art, this very simple realisation of new-physics extension of the SM seems to be insufficient, wth some troubles which arise if we try to achieve our initial tasks in one single shot. The other modification of the SM that we consider deals with the inclusion of a non-minimal coupling between the Higgs field, still playing the role of inflaton, and gravity. Here, we put some weak constraints on the tensor-to-scalar-ratio in the low-\xi parameter space, in order to evade the intrinsic unitarity issues of the model.
La scoperta del bosone di Higgs a LHC e la determinazione del valore della sua massa ha aperto la possibilità di studiare il Modello Standard (MS) fino ad alte energie, rendendo possibile la verifica della consistenza della teoria e del suo range di validità, dal momento che lo consideriamo come un modello effettivo. In questo scenario, facendo uso dei dati sperimentali più aggiornati, molto interesse è stato riposto nello studio della stabilità del vuoto elettrodebole del MS e le sue particolari implicazioni sia nella fisica delle particelle che, soprattutto, in cosmologia. Il nostro lavoro si inserisce in questo contesto con un doppio fine: da un lato, proviamo a raffinare i più recenti calcoli dei vincoli di stabilità, alla luce dei dati sperimentali e degli approcci teorici più aggiornati, soprattutto relativi alla tecnica del potenziale effettivo; mentre, dall'altro lato, usiamo i risultati di questa analisi per studiare e porre vincoli ad alcune realizzazioni di inflazione cosmica nel contesto del puro MS e di sue estensioni minime. In particolare, abbiamo studiato alcune osservabili \emph{gauge}-indipendenti legate a due configurazioni stazionarie del potenziale del MS, estrapolato ad alte energie grazie all'approccio che fa uso del potenziale effettivo e delle equazioni del gruppo di rinormalizzazione, nella loro forma più aggiornata, vale a dire il NNLO: il valore della massa del quark top in corrispondenza del quale si ha la stabilità dle vuoto elettrodebole (criticality) e il potenziale valutato nel suo punto di flesso. Dimostrata l'indipendenza dalla scelta del gauge di queste osservabili, sono state stimate le incertezze relative. Il primo risultato rilevante, in accordo con la letteratura (con qualche discrepanza), è che la stabilità assoluta del MS non è completamente esclusa, data l'attuale finestra sperimentale: è, in linea di principio, possibile assumere il MS valido fino alla scala di Planck, dove ci aspettiamo che l'interazione gravitazionale cominci a diventare rilevante, senza alcuna inclusione di nuova fisica a basse scale energetiche ("desert scenario"). Partendo da questo punto, abbiamo provato a spiegare la fase inflazionaria primordiale all'interno del puro MS, sfruttando la configurazione del punto di flesso. Tuttavia, mostriamo che diventa in questi casi molto difficile riprodurre gli attuali vincoli sul rapporto tensore/scalare. Vista la necessità di introdurre nuovi gradi di libertà per includere nella teoria un ragionevole meccanismo per l'inflazione cosmica e, in maniera consistente, una stabilizzazione per il potenziale del MS, proviamo a passare in rassegna le principali caratteristiche di una delle possibili estensioni minime al MS, attraverso una simmetria globale U(1)_B-L, e a porre dei vincoli ai parametri propri del nuovo modello, in maniera tale da riuscire a raggiungere entrambi gli obiettivi. Lo scalare extra associato alla rottura di questa nuova simmetria, oltre a garantire la stabilizzazione mediante un effetto di soglia al tree-level, sarebbe responsabile della generazione della massa di un neutrino right-handed, che, a sua volta, fornisce, attraverso il meccanismo see saw di tipo I, le masse dei neutrini di bassa energia. In questo contesto, troviamo la finestra dei parametri accessibile sia per una fase inflazionaria funzionale, guidata dallo stesso scalare massivo, che per la stabilizzazione del modello: confermiamo i risultati riportati in letteratura, nonostante i lavori rilevanti svolgono le loro analisi o in configurazioni leggermente differenti, oppure raffrontano i loro risultati con vincoli sperimentali più datati, giungendo poi dunque a conclusioni diverse. Ad ogni modo, facendo riferimento allo stato dell'arte attuale dal punto di vista sperimentale, questa semplice realizzazione di estensione con nuova fisica del MS sembra non essere sufficiente. Una applicazione allo scenario con accoppiamento non minimale viene anche considerata.
Los estilos APA, Harvard, Vancouver, ISO, etc.
5

Cacciapaglia, Giacomo. "Models of electroweak symmetry breaking in extra dimensions". Doctoral thesis, Scuola Normale Superiore, 2007. http://hdl.handle.net/11384/85850.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
6

Cárcamo, Hernández Antonio Enrique. "Composite Vectors and Scalars in Theories of Electroweak Symmetry Breaking". Doctoral thesis, Scuola Normale Superiore, 2011. http://hdl.handle.net/11384/85833.

Texto completo
Resumen
In the context of a strongly coupled Electroweak Symmetry Breaking, composite triplet of heavy vectors belonging to the SU(2)L+R adjoint representation and a composite scalar singlet under SU(2)L+R may arise from a new strong interaction invariant under the global SU(2)L x S(2)R symmetry, which is spontaneously broken down to SU(2)L+R. This thesis consists of two parts. The first part is devoted to the study of the heavy composite vector pair production at the LHC via Vector Boson Fusion and Drell-Yan annihilation under the assumption that the interactions among these heavy vector states and with the Standard Model gauge bosons are described by a SU(2)L x SU(2)R=SU(2)L+R Effective Chiral Lagrangian. The expected rates of multi-lepton events from the decay of the composite vectors are also given. The second part studies the associated production at the LHC of a composite vector with a composite scalar by Vector Boson Fusion and Drell-Yan annihilation in the framework of a SU(2)L x SU(2)R=SU(2)L+R Effective Chiral Lagrangian with massive spin one fields and one singlet light scalar. The expected rates of same sign di-lepton and tri-lepton events from the decay of the composite vector and composite scalar final state are computed. The connection of the Effective Chiral Lagrangians with suitable gauge models is elucidated.
Los estilos APA, Harvard, Vancouver, ISO, etc.
7

Papucci, Michele. "Electroweak Symmetry Breaking with a compact extra dimension". Doctoral thesis, Scuola Normale Superiore, 2009. http://hdl.handle.net/11384/85837.

Texto completo
Resumen
[Excerpt from the preface]: During my Ph.D. course, under the supervision of Riccardo Barbieri, I started working on Theoretical High Energy Physics. In particular I focused on the problem of Electroweak Symmetry Breaking and in this context I investigated the bene ts of introducing a compact extra dimension. In a series of papers, together with Riccardo Barbieri, Guido Marandella, Lawrence Hall, Yasunori Nomura, Takemichi Okui and Steven Oliver I built supersymmetric models in 5D and studied their phenomenology in detail [1, 2, 3, 4]. In this models Supersymmetry is broken by boundary conditions in the fth dimension and the ElectroWeak Symmetry Breaking is triggered by Supersymmetry breaking via the top/stop radiative corrections. The phenomenology of these models is signi cantly di erent than the one of the Minimal Supersymmetric Standard Model scenarios extensively studied in the literature. These papers constitute the subject of this Thesis and their results will be presented in the following Chapters.
Los estilos APA, Harvard, Vancouver, ISO, etc.
8

Macorini, Guido. "One loop electroweak corrections for single top production at LHC". Doctoral thesis, Università degli studi di Trieste, 2008. http://hdl.handle.net/10077/2708.

Texto completo
Resumen
2006/2007
In this thesis we report and discuss the results for the first complete calcula- tion of the one-loop electroweak corrections for the two dominant processes of single Top production at the Large Hadron Collider: the tW-associated pro- duction and the t-channel process. We calculate the corrections working both in the Standard Model (SM) and in the minimal supersymmetric extension of the Standard Model (MSSM, as- suming a mSUGRA scenario), analysing the effect of the corrections on several observables and trying to understand whether deviations from the Standard Model prediction could be observable. The single Top production is the main source of information about the Top weak interaction, and a privileged laboratory to understand the symmetry breaking in the weak sector. Moreover at the hadronic colliders the single Top processes provide the only known way to measure directly the Vtb element of the CKM matrix, providing a fundamental test of the Standard Model struc- ture. For the tW production process we present the complete calculation of the one- loop electroweak effect, including the effect of the hard real photon emission; we combine our results with the available calculation for the QCD and SUSY QCD corrections, providing a complete one loop description of the process. Our interest has been concentrated on the particular quantities that we have defined as partial rates, with special emphasis on the low (400 GeV) final in- variant mass. In this region with the addition of SUSY QCD one-loop terms, the genuine SUSY contribution reaches an interesting 10% size. The analysis of t-channel process is limited to the pure electroweak componet (adding the soft photon emission only, to cancel the infrared divergences aris- ing from diagrams with virtual photon). The electroweak corrections for the t-channel are less sensitive to the presence of the SUSY particles: this conclusion holds for all the four examined bench- mark points in themSUGRA scheme. In addition, considering the small contri- bution of the known SUSY QCD corrections, we conclude that in themSUGRA scenario it will be probably impossible to detect at the LHC any deviation from the SM predictions. In the SMcontext the size of the electroweak correctionswithout the hard emis- sion seems to be very large, but we expect that the total effect should be con- siderably reduced adding the hard emission part.
Nella tesi vengono riportati e discussi i risultati per il calcolo completo delle correzioni radiative elettrodeboli ad un loop per i due processi dominanti nella produzioe di quark Top singoli al Large Hadron Collider: la produzione associata tW e il processo di "canale t". Le correzioni ad un loop sono calcolate sia nelModello Standard (SM) che nella sua estensione supersimmetrica minimale (MSSM, assumendo uno scenario di mSUGRA); si è quindi analizzato l’effetto delle correzioni su varie osservabili fisiche, tentando di comprendere se siano riscontrabili deviazioni misurabili dalle predizioni del Modello Standard. La produzione di quark Top singoli costituisce la principale fonte di informzioni riguardo le interazioni deboli del Top e per lo studio e la comprensione della rottura della simmetria elettrodebole. Inoltre ai collider adronici la produzione di quark Top singoli costituisce l’unico processo che permette una misura diretta dell’elemento Vtb della matrice CKM, costituendo dunque un test fondamentale per la struttua del Modello Standard. Per la produzione associata tW si presenta il calcolo completo dell’effetto elettrodebole ad un loop, includendo poi l’effetto dell’emissione di fotoni duri; si combinano dunque i nostri risultati con i risultati (noti in letteratura) per le correzioni di QCD e QCD supersimmetrica, fornendo una descrizione completa ad un loop del processo. Abbiamo concentrato il nostro interesse su paticolari osservabili dette "rate parziali", con speciale attenzione alla regione di bassemasse invarianti: in data regione, tenendo conto delle correzioni di QCD supersimmetrica, il contributo genuinamente supersimmetrico dell’effetto ad un loop raggiunge il 10%, costituendo una deviazione potenzialmente osservabile. L’analisi del canale t è limitata alla sola componente elettrodebole (con l’aggiunta dell’emissione di fotini "soft", in modo da ottenere un risultao IR-finito): le correzioni ad un loop elettrodeboli per questo processo si sno rivelate meno sensibili alla presenza di eventuali particelle supersimmetriche; questa conclusione è comune nei quatro scenari mSUGRA analizzati. Considerando inoltre che l’effetto della QCD supersimmetrica è piccolo, si può concludere che sarà verosimilmente impossibile osservare deviazioni dalle predizioni SM. Nel Modello Standard le correzioni dovute alla parte elettrodebole sembrano numericamente molto significative, ma ci può aspettare una drastica riduzione di tale effetto una volta aggiunta l’emissione di fotoni reali "hard".
XX Ciclo
1978
Los estilos APA, Harvard, Vancouver, ISO, etc.
9

GRANATA, FEDERICO. "Electroweak and strong next-to-leading-order corrections to HV and HVj production at hadron colliders". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/158128.

Texto completo
Resumen
La scoperta del bosone di Higgs a LHC al CERN ha dato il via a un'era senza precedenti nel campo delle misure di precisione. In vista delle imminenti misure dai Run a 13 TeV di LHC è fondamentale avere previsioni accurate per processi che coinvolgono la produzione di un bosone di Higgs, per investigare a fondo il fenomeno di rottura spontanea della simmetria elettrodebole. Alle energie raggiunte da LHC, le correzioni dominanti provengono dal settore di QCD, in cui il primo ordine perturbativo (NLO) tipicamente dà contributi del 20-30% alla sezione d'urto. Le correzioni NLO elettrodeboli (EW), invece, ammontano al 5-10%, comparabili col secondo ordine perturbativo di QCD. Anche se il loro effetto è moderato sulla sezione d'urto totale, le correzioni NLO EW modificano l'andamento di molte grandezze cinematiche, come le code ad alta energia di alcune distribuzioni di momento trasverso. Inoltre, svolgono un ruolo importante nello studio della materia oscura e nella sua rivelazione indiretta. Una conoscenza precisa di queste distribuzioni, considerando anche le correzioni EW, è quindi fondamentale per verificare la validità di questi modelli. Il settore EW presenta molte differenze rispetto alla QCD. Poiché in QED e QCD le correzioni virtuali e reali coinvolgono lo scambio di particelle massless, esse sono separatamente divergenti, e solo la loro somma è finita. In queste teorie, quindi, l'inclusione delle correzioni reali è obbligatoria. Considerando correzioni deboli, invece, per via dello scambio di particelle massive, tutti i contributi alla sezione d'urto NLO sono finiti. Inoltre, le particelle emesse decadono, dando stati finali che possono essere sperimentalmente distinti da quelli al leading order. Non ci sono ragioni tecniche, quindi, per includere l'emissione reale di bosoni W e Z. Considerando solo correzioni virtuali EW compaiono dei logaritmi del rapporto tra l'energia del processo e la scala EW, che rappresenterebbero la parte divergente delle correzioni virtuali se le particelle scambiate fossero massless. Queste correzioni diventano rilevanti a energie dell'ordine del TeV, dove danno solitamente notevoli contributi negativi alle code ad alta energia di alcune distribuzioni di momento trasverso. È stato dimostrato che, nel limite in cui tutti gli invarianti cinematici sono dello stesso ordine e molto maggiori della scala EW, la struttura delle correzioni EW virtuali è universale: può quindi essere calcolata una volta per tutte, e poi applicata ai processi desiderati. Questi risultati possono essere utilizzati per ottenere, con un costo computazionale ridotto, un'approssimazione next-to-leading logarithimic (NLL) delle correzioni EW virtuali complete. Questa tesi è incentrata sulla descrizione di due tipi di processi che coinvolgono la produzione di un bosone di Higgs, includendo correzioni sia di QCD sia EW. Il primo processo è uno dei principali modi di produrre il bosone di Higgs in collisori adronici: la produzione associata con un vettore bosone, HV. Questo processo è molto importante, perché permette di studiare il canale di decadimento in una coppia di quark bottom, che ha il più alto branching ratio nella regione di massa del bosone di Higgs. Il secondo processo rilevante è la produzione associata con un bosone vettore e un jet, HVj, che contribuisce al background per eventi supersimmetrici. Allo stato attuale, i processi HV e HVj sono descritti con un'accuratezza NLO+PS in QCD. L'accuratezza NLO+PS nel settore EW è tuttora mancante. Lo scopo di questa tesi è quindi la descrizione dei processi di produzione associata HV e HVj con accuratezza NLO+PS QCD+EW. Sono state effettuate previsioni teoriche per collisioni protone-protone a un'energia del centro di massa di 13 TeV, concentrandosi su osservabili sensibili alle correzioni EW. Per ogni processo vengono analizzate le differenze tra le correzioni NLO EW e la loro approssimazione NLL, e l'impatto del settore EW sui risultati di QCD.
The discovery of the Higgs boson at the CERN Large Hadron Collider (LHC) has opened an unprecedented era in the field of precision measurements. In view of the upcoming data from the 13 TeV Run of the LHC, accurate predictions for processes that involve the production of the Higgs boson are fundamental, in order to further investigate the phenomenon of electroweak symmetry breaking. At the energies reached by the LHC, the dominant corrections come from the QCD sector, where the first perturbative order (NLO) typically gives a contribution of 20-30% to the cross section. Electroweak (EW) NLO corrections, instead, amount to 5-10%, comparable with the second QCD perturbative order. Even if their effect is rather mild on the integrated cross sections, NLO EW corrections are known to alter the shape of many kinematic quantities, like the high-energy tails of some transverse-momentum distributions. Moreover, they play an important role in the study of the nature of dark matter and in its indirect detection. A precise knowledge of the high-energy tails, including EW corrections, is then mandatory in order to test the validity of these models. The EW sector has many differences with respect to QCD. Since in QED and QCD the virtual and real corrections involve the exchange of massless particles, they are separately divergent, and only their sum is finite. In these theories, then, the inclusion of real corrections is mandatory. When considering weak corrections, instead, because of the exchange of massive bosons, all the contributions to the NLO cross section are finite. Moreover, the radiated particles would subsequently decay, giving final states that can be experimentally distinguished from the leading-order ones. There are no technical reasons, then, to include the real emission of W and Z bosons. The result of considering only virtual EW corrections is the appearance of logarithms that involve the ratio between the energy of the process and the EW scale. They would represent the divergent part of the virtual corrections if the exchanged bosons were massless. These corrections become relevant at the TeV scale, where they usually give sizable negative contributions in the high-energy tails of some transverse-momentum distributions. It has been proven that, in the limit in which all the kinematic invariants involved are of the same order and much greater than the EW scale, the structure of EW virtual corrections is universal: it can then be computed once for all and applied to the desired processes. These high-energy results can be used to obtain a next-to-leading logarithmic (NLL) approximation of the complete EW virtual corrections with a reduced computational cost. This thesis is focused on the description of two kinds of high-energy processes that involve the production of a Higgs boson, including both QCD and EW corrections. The first process is one of the main production modes of the Higgs boson at hadron colliders: the associated production with a vector boson, HV. This process is very important, since it allows to study the decay channel into a bottom-quark pair, that has the highest branching ratio in the Higgs boson mass region. The second relevant process analyzed is the associated production with a vector boson and a jet, HVj, that contributes to the background for supersymmetric events. At present, both the HV and Hvj processes are described at NLO+PS QCD accuracy. The NLO+PS accuracy in the EW sector is instead missing. The aim of this thesis is the description of the HV and HVj associated production processes at NLO+PS QCD+EW accuracy. We present numerical predictions for proton-proton collisions at a center-of-mass energy of 13 TeV, focusing on observables that are sensitive to EW corrections. For each process, we analyze the differences between the NLO EW corrections and their NLL approximation, and the impact of the EW sector on the QCD results.
Los estilos APA, Harvard, Vancouver, ISO, etc.
10

Panizzi, Luca. "One loop electroweak analysis for third family scalar quarks production at LHC". Doctoral thesis, Università degli studi di Trieste, 2009. http://hdl.handle.net/10077/3064.

Texto completo
Resumen
2007/2008
The thesis is devoted to the analysis of electroweak one-loop corrections to processes of production of scalar quarks of the third family at the Large Hadron Collider (LHC) in the context of the minimal supersymmetric extension of the Standard Model (MSSM). Third family squarks are are predicted to be among the lightest supersymmetric particles, hence they could be among the first signals of new physics to be detected at the LHC. Moreover, a very light stop (with a mass of the same order of the top mass) might play a relevant role within a cosmological model of electroweak baryogenesis. A precise analysis of one-loop corrections to processes of production of stop and sbottom particles and the determination of theoretical predictions to be tested against LHC data are therefore mandatory to understand the properties of these particles. The EW NLO corrections to the most meaningful observables related to these processes (differential and total cross sections) have been calculated and the dependence on supersymmetric parameters of the considered observables has been analysed. The considered processes are: 1) PP -> gg -> stop-antistop (sbottom-antisbottom); 2) PP-> bg -> stop-chargino. In both cases the analysis has been performed within various mSUGRA scenarios. For this purpose three C++ codes which exploit Monte Carlo techniques for the integration of cross sections have been developed. For the stop-antistop production case the diagonal production shows a total cross section of the order of 10 picobarns in some scenarios which predict a light stop; electroweak corrections, however, are of the order of few percent for every scenario considered; through the definition of the partial rates it is possible to obtain correction near to 10% in the high invariant mass region. The analysis of the dependence of one-loop corrections on mSUGRA parameters has been performed and it has been verified that the dependence is quite mild (variations up to 4%). In the case of sbottom production the total cross sections are generally smaller than 1pb and the one-loop corrections are not very sizable. As far as the parametric dependence is concerned, for diagonal production of light sbottom an interesting dependence on the parameter tg(beta) has been found in a particular scenario. For the stop-chargino production process the total cross sections are of the order of the picobarn in scenarios where stop and charginos are not too massive. The one-loop corrections are of the order of few percent and, due to the small cross sections in the considered scenarios, they are unfortunaltely quite difficult to observe at the LHC; the analysis through the partial rates predicts higher corrections, though difficult to detect. Due to these results, the parametric analysis has been performed at tree level, where the observables depend on a limited number of supersymmetric parameters: the strongest dependence has been found to be on the stop mixing angle and on the supersymmetric parameter mu. The analysis of stop production processes within scenarios of electroweak baryogenesis has been performed in both cases. For the case of diagonal production of light stop-antistop pairs, the electroweak one-loop effect on the total cross section has been found to be quite mild. Due to the small stop mass the total cross section is however of the order of 10pb. Therefore, through the analysis of partial rate it is possible to predict effects of the order of 10% with a still detectable cross section. In the stop-chargino case, the total cross section has been found to be smaller than 1pb even in the lightest configuration, and the one-loop correction is 2%.
La presente tesi consiste nell'analisi delle correzioni elettrodeboli a 1 loop di alcuni processi di produzione di quark scalari della terza famiglia al Large Hadron Collider nell'ambito dell'estensione supersimmetrica minimale del Modello Standard (MSSM). Gli squark della terza famiglia sono particolarmente importanti perché si prevede che siano fra le particelle supersimmetriche più leggere, e per questo motivo potrebbero essere fra i primi segnali di nuova fisica ad essere osservati all'LHC. Inoltre, uno stop particolarmente leggero (con una massa dello stesso ordine di quella del top) potrebbe giocare un ruolo rilevante nell'ambito di un modello cosmologico di bariogenesi elettrodebole. Una precisa analisi delle correzioni a 1 loop dei processi di produzione di stop e sbottom con la determinazione di previsioni teoriche da verificare sperimentalmente ad LHC è quindi fondamentale per cercare di comprendere le proprietà di queste particelle. In questa tesi vengono calcolate le correzioni sui principali osservabili legati a questi processi (sezioni d'urto differenziali e totali) e viene analizzata la dipendenza dai parametri supersimmetrici degli osservabili considerati. I processi analizzati sono: 1) PP -> gg -> stop-antistop (sbottom-antisbottom); 2) PP -> bg -> stop-chargino. In entrambi i casi l'analisi è stata effettuata nel contesto di diversi scenari mSUGRA. Sono stati sviluppati per questo scopo tre codici in C++ che si avvalgono di tecniche di Monte Carlo per l'integrazione delle sezioni d'urto. Nel caso del processo di produzione di stop, si è verificato che per alcuni scenari che prevedono uno stop leggero, la produzione diagonale ha una sezione d'urto totale dell'ordine della decina di picobarn; le correzioni elettrodeboli però sono dell'ordine di qualche punto percentuale per tutti gli scenari considerati; tramite la definizione delle cosiddette rate parziali è possibile ottenere correzioni vicine al 10% nella regione di alte masse invarianti. E' stata poi eseguita un'analisi di come gli effetti a un loop dipendono dai parametri mSUGRA, verificando che la dipendenza è poco apprezzabile (variazioni del 4%). Nel caso di produzione di sbottom le sezioni d'urto sono generalmente inferiori al picobarn e le correzioni a 1 loop rimangono abbastanza limitate. Per quanto riguarda la dipendenza parametrica, per produzione diagonale di sbottom leggeri c'è una interessante dipendenza dal parametro tg(beta) in un particolare scenario supersimmetrico. Nel caso del processo di produzione di stop-chargino la sezione d'urto è dell'ordine del picobarn nei casi che prevedono stop e chargini non eccessivamente massivi. Anche in questo caso le correzioni a 1 loop sono di qualche punto percentuale, difficilmente visibili a LHC a causa delle basse sezioni d'urto negli scenari considerati; l'analisi delle rate parziale consente di ottenere correzioni maggiori, ma difficilmente osservabili. A causa della scarsa visibilità del processo, l'analisi parametrica è stata effettuata a livello albero, dove gli osservabili dipendono da un numero limitato di parametri supersimmetrici: la dipendenza maggiore risulta essere per l'angolo di mixing dello stop e dal parametro supersimmetrico mu. Per quanto riguarda l'analisi dei processi di produzione di stop nell'ambito di scenari di bariogenesi elettrodebole, nel caso di produzione diagonale di stop leggeri, l'effetto a 1 loop è scarso, ma data la piccola massa dello stop che determina una sezione d'urto dell'ordine della decina di picobarn, l'analisi della rate parziale permette di prevedere effetti dell'ordine del 10%. Nel caso di stop-chargino la sezione d'urto risulta essere inferiore al picobarn anche nella configurazione più leggera e la correzione a 1 loop è del 2%.
XXI Ciclo
1980
Los estilos APA, Harvard, Vancouver, ISO, etc.

Actas de conferencias sobre el tema "Electroweak fit"

1

Erler, Jens y Tony M. Liss. "Fit to Electroweak Precision Data". En INTERSECTIONS OF PARTICLE AND NUCLEAR PHYSICS: 9th Conference CIPAN2006. AIP, 2006. http://dx.doi.org/10.1063/1.2402624.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
2

Fischer, Yannick, Johannes Haller, Andreas Hoecker, Roman Kogler, Klaus Mönig y Jörg Stelzer. "The global electroweak fit in the SM and SMEFT". En The European Physical Society Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2024. http://dx.doi.org/10.22323/1.449.0304.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
3

LI, Gang. "Electroweak and QCD Combined Fit of HERA-II Data". En 15th International Workshop on Deep-Inelastic Scattering and Related Subjects. Amsterdam: Science Wise Publishing, 2007. http://dx.doi.org/10.3360/dis.2007.47.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
4

SCHOTT, Matthias. "The global electroweak fit and constraints on new physics". En XXIst International Europhysics Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2012. http://dx.doi.org/10.22323/1.134.0254.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
5

Ludwig, Dörthe. "The global electroweak fit and constraints on new physics". En 35th International Conference of High Energy Physics. Trieste, Italy: Sissa Medialab, 2011. http://dx.doi.org/10.22323/1.120.0404.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
6

CHIERICI, R. "ELECTROWEAK PHYSICS AT LEP2 AND THE FIT TO THE STANDARD MODEL". En Proceedings of the 10th International Symposium. World Scientific Publishing Company, 2005. http://dx.doi.org/10.1142/9789812701756_0036.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
7

Peiffer, Thomas, Max BAAK, Jakub Cuth, Johannes Haller, Andreas Hoecker, Roman Kogler, K. Moenig, Matthias SCHOTT y Joerg Stelzer. "The global electroweak fit at NNLO and constraints on new physics". En The European Physical Society Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.234.0100.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
8

Mele, Salvatore. "Combined fit to the electroweak data and constraints on the Standard Model". En International Europhysics Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2001. http://dx.doi.org/10.22323/1.007.0127.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
9

Britzger, Daniel y Hubert Spiesberger. "Fit of electroweak parameters in polarized deep-inelastic scattering using data from the H1 experiment". En XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.265.0048.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
10

Britzger, Daniel y Hubert Spiesberger. "Fit of electroweak parameters in polarized deep-inelastic scattering using data from the H1 experiment". En 38th International Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2017. http://dx.doi.org/10.22323/1.282.0676.

Texto completo
Los estilos APA, Harvard, Vancouver, ISO, etc.
Ofrecemos descuentos en todos los planes premium para autores cuyas obras están incluidas en selecciones literarias temáticas. ¡Contáctenos para obtener un código promocional único!

Pasar a la bibliografía