Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"Effective Field Theories"”.
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Effective Field Theories in Cosmology
… physical origin of the cosmological constant. Effective field theory methods provide a natural framework to try to address such outstanding questions. For instance, such methods have been extensively used to study alternative theories of gravity which mimic a non-vanishing cosmological constant …
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Effective field theories for the LHC
In this thesis I study applications of effective field theories to understand aspects of QCD jets and their substructure at the Large Hadron Collider. In particular, I introduce an observable, D2 , which can be used for distinguishing boosted W/Z/H bosons from the QCD background using information …
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Heavy quarks in effective field theories
… several aspects of heavy quark systems in an effective field theory framework, including both phenomenological and formal applications. Phenomenological applications include the leading calculation of penguin amplitudes in charmless non-leptonic B-decays to light mesons, including power …
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Top mass determination using Effective Field Theories
… due to lack of specification of a precise field theoretic definition. Here a kinematic extraction method for obtaining a precisely defined short distance top mass at the LHC is proposed. A formula for factorized top jet mass cross section in the peak region is derived using methods of …
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Effective field theories for inclusive B decays
… the Standard Model. We use the framework of effective field theories, in particular the Soft-Collinear Effective Theory, which is a suitable method when the decay products include a jet-like set of hadronic states. We derive factorization theorems for ... corrections (including all orders in …
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Gravitational Effective Field Theories and Black Hole Mechanics
… to GR. One approach is the framework of effective field theory (EFT), where the Lagrangian is treated as a series of higher derivative terms scaling with some UV parameter beyond which we have "integrated out" the unknown physics. This thesis is concerned with studying two issues in …
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Precision QCD and effective field theories with machine learning
… data using a global QCD analysis. In tandem, Effective Field Theories (EFTs), provide a convenient framework to capture the indirect effects of possible BSM resonances in low energy observables. Constraints on the EFT then translate to constraints on the nature of BSM physics. This manuscript …
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Symmetries, unitarity and positivity of cosmological effective field theories
… challenges at the interface between Quantum Field Theory (QFT) and General Relativity (GR). The time dependence of cosmological spacetimes, upon which quantum fields propagate, spontaneously breaks time translation and Lorentz boost invariance. Thus the usual tools of particle physics, which …
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Effective Field Theories for Physics Beyond the Standard Model
… beyond the Standard Model will be heavy. An effective field theory (EFT) provides a powerful framework for capturing the indirect effects of heavy new physics on low-energy observables. This thesis will explore the use of EFTs in the search for new physics beyond the Standard Model, taking …
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The Use of Operator Regularization in the Computation of Effective Field Theories
<p>Current methods of computing low-energy effective field theories while being accurate are extremely cumbersome co implement. Operator regularization provides a way to calculate any desired effective field theory avoiding the tediousness of previous methods. This technique is shown to be an …
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Light Hadron Properties From Lattice QCD
… with the tools of lattice calculations and effective field theories.</p><p>The two and three flavor effective field theories are applied to pions and kaons respectively to study the quark mass dependence of their masses and decay constants. In addition, the phenomenologically interesting …
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Applying SCET to parton showers
… parton showers in the context of soft collinear effective theory (SCET). Monte Carlo event generators like Pythia or Herwig are heavily used by experimentalists to simulate events and they are indispensable tools to make exclusive theoretical predictions. They are based on a leading log parton …
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Challenges to Effective Realism
That a theory is merely effective has historically counted against it, especially in pro-realism discourse. For example, many realists take the interpretation of a theory to amount to specifying what the world would be like was the theory true (or characterizing the possible worlds picked out by …
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Weak Decay Studies From An Effective Theory Standpoint
… using a model independent approach by employing effective field theories. I discuss the soft photon contribution and background effect to the rare dimuonic decay of the neutral B meson. I also study some radiative exclusive W boson decays in the standard model in the context of pQCD and SCET. …
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Exotic States in Quarkonium Physics: Effective Theories of Heavy Mesonic Molecules and an AdS/QCD Model of Hybrid Quarkonium
… Two approaches to achieve</p><p>this end are effective field theories and gauge/gravity dualities. The former involves</p><p>a field theory more or less like QCD itself, but with states which are composites</p><p>of quarks and gluons. Then a perturbative expansion is made not in terms of …
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Probing Lepton Flavour Universality With $\bz \to \kstarz \taup \taum$
… at the violation of lepton flavour universality. Effective field theories which attempt to find an explanation for these anomalies predict sizeable enhancements to the rate of $\bquark \to \squark \taup \taum$ currents. We use $pp$ collision data collected by the LHCb detector to estimate a …
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The Cauchy problem and the initial data problem in effective theories of gravity
Lovelock and Horndeski theories of gravity are diffeomorphism-invariant theories with second-order equations of motion. A subset of these theories can be motivated by effective field theory considerations and hence they could describe strong-field deviations from general relativity. In particular, …
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Effective Computational Cosmology
<p>Effective Field Theories (EFTs) provide a unique framework in which to attempt to answer outstanding questions in cosmology (and all field of physics, for that matter). This work investigates how the use of both EFTs and computational tools can help us to advance our knowledge of how the …
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Nanostructures and alloys : multiple scattering and nonlinearities in phonon transport
… conductivity in semiconductors and dielectrics. Effective field theories and scattering theory have been combined to model alloys and systems with embedded nanostructures. The simplest of such effective field theories, the Virtual Crystal approximation, fails to capture short-length scale …
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