The Effective Field Theory formalism is applied to the study of problems in hadronic and nuclear physics. We develop a framework to study the exclusive two-body decays of bottomonium into two charmed mesons and apply it to study the decays of the C-even bottomonia. Using a sequence of effective field theories, we take advantage of the separation between the scales contributing to the decay processes, 2m(b) ≫ m(c) ≫∧(QCD). We prove that, at leading order in the EFT power counting, the decay rate factorizes into the convolution of two perturbative matching coefficients and three non-perturbative matrix elements, one for each hadron. We calculate the relations between the decay rate and non-perturbative bottomonium and D-meson matrix elements at leading order, with next-to-leading log resummation. The phenomenological implications of these relations are discussed. At lower energies, we use Chiral Perturbation Theory and nuclear EFTs to set up a framework for the study of time reversal (T) symmetry in one- and few-nucleon problems. We consider T violation from the QCD θ term and from all the possible dimension 6 operators, expressed in terms of light quarks, gluons and photons, that can be added to the Standard Model Lagrangian. We construct the low energy chiral Lagrangian stemming from different TV sources, and derive the implications for the nucleon Electric Dipole Form Factor and the deuteron T violating electromagnetic Form Factors. Finally, with an eye to applications to nuclei with A ≥ 2, we construct the T violating nucleon-nucleon potential from different sources of T violation.

<p>Quantum chromodynamics (QCD), the theory of quarks and gluons, is known to be</p><p>the correct description of strong nuclear interactions. At high energy and momenta,</p><p>one can use QCD directly to compute quantities of physical interest related to the</p><p>strong force. At low energies and momenta, one should use a different description in</p><p>terms of the degrees of freedom relevant at that scale. 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 the</p><p>gauge coupling but instead in terms of the momentum of the fields. This approach</p><p>dates back to the 1970s and is on firm theoretical footing. Gauge/gravity dualities</p><p>are a newer and less understood technique, which relates the physics of the strong</p><p>interactions to a different but likely equivalent theory in a higher dimensional space-</p><p>time, where the quantity of interest can be computed more readily. We employ</p><p>both effective field theories and gauge/gravity dualities to study the physics of ex-</p><p>otic quarkonium states, that is bound states containing a heavy quark-antiquark pair</p><p>which nevertheless cannot be be understood working only with the standard quark</p><p>model of hadrons. Candidates for such states, long speculated to exist, have recently</p><p>been observed at particle colliders, so that the theory of exotic quarkonium is now</p><p>of great experimental importance.</p> / Dissertation

Au cours des dernières décennies, des théories effectives des champs (TEC) ont été largement utilisées comme approche de la physique à interaction forte et à faible énergie (régimes nucléaires et hadroniques). Dans cette thèse, nous explorons en détail trois exemples d'applications du programme des TEC au système NN dans l'état de spin singulet (onde S et ondes périphériques respectivement) et aux molécules théorisées de mésons lourds DDs0* et D*Ds1*. / During the last few decades, effective field theories (EFT) have been widely used as an approach to low-energy strong-interacting physics (nuclear and hadronic regimes). In this thesis, we will explore in detail three examples of applications of the EFT program to the spin-singlet NN system (S wave and peripheral waves respectively) and to the theorized heavy-meson molecules DDs0* and D*Ds1*.

Gittersimulationen der Quantenchromodynamik ermöglichen eine vollständig nichtperturbative Berechnung hadronischer Korrelationsfunktionen, allerdings müssen die Beiträge angeregter Zustände unter Kontrolle sein um verlässlich physikalische Größen wie Teilchenenergien und Matrixelemente extrahieren zu können. In dieser Arbeit wird eine effektive Feldtheorie, die Chirale Störungstheorie Schwerer Mesonen (ChSTSM), verwendet um die dominanten Beiträge der angeregten Zustände in B Meson Korrelationsfunktionen, die zur Extraktion von CKM Matrixelementen verwendet werden, analytisch zu bestimmen. Zuerst werden die Analoga der Quarkbilineare, die als interpolierende Felder in Gittersimulationen verwendet werden, in der ChSTSM hergeleitet. Diese hängen von Niedrig-Energie-Konstanten (NEKs) ab, deren Werte für lokale Felder bekannt sind. Geschmierte interpolierende Felder kann man andererseits durch verändern dieser numerischen Werte beschreiben. Dies wird im Laufe der Arbeit mehrfach genutzt um den Einfluss des Schmierens zu untersuchen. Mit den Feldern kann die Zweipunkt-Funktion des B Meson berechnet werden, aus der seine Masse und Zerfallskonstante sowie die jeweiligen Beiträge der angeregten Zustände bestimmt werden können. Aus Quotienten von passend gewählten Drei- und Zweipunkt-Funktionen werden weiterhin die ChSTSM NEK g, die Formfaktoren des semileptonischen B Zerfalls und die Matrixelemente, die neutrale B Oszillationen beschreiben, sowie die dominanten Beiträge der angeregten Zustände bestimmt. Letztere führen, abhängig von den Werten der NEKs, meist zu einem um ein paar Prozent höheren Wert für die Quotienten. Einige Ergebnisse hängen zusätzlich von weiteren unbekannten NEKs ab. Für diese werden Korrelationsfunktionen angegeben aus denen sie mittels Gitterrechnungen bestimmt werden können. Im Gegensatz zu den vorherigen Ergebnissen sind die Beiträge der angeregten Zustände für einen der semileptonischen Formfaktoren eine Größenordnung größer und negativ. / Lattice simulations of Quantum Chromodynamics allow for a fully non-perturbative computation of hadronic correlation functions, but for a reliable extraction of physical quantities such as particle energies and matrix elements the contribution of excited states needs to be under control. In this thesis, an effective field theory known as Heavy Meson Chiral Perturbation Theory (HM ChPT) is used to analytically compute the dominant excited states contamination of B meson correlators which are relevant for the extraction of CKM matrix elements. First, the analogues of the quark bilinears which are used as interpolating fields in lattice simulations are derived in HM ChPT. These depend on a set of low energy constants (LECs) which are known for local fields. On the other hand, smeared interpolating fields can be incorporated in the effective theory by changing the values of these LECs, a fact that will be used throughout this thesis for investigating the effect of smearing. The interpolating fields are used to compute the B meson two-point function from which the B meson mass and decay constant as well as the respective excited states contamination can be extracted. From suitably chosen ratios of three-point functions and two-point functions, the HM ChPT LEC g, the form factors of semileptonic B meson decay, and the matrix elements of neutral B meson oscillations were determined. The computed excited states contamination of these ratios usually leads to an overestimation of the order of a few percent, depending on the values chosen for the LECs. Some results depend on so far unknown LECs, for which suitable correlation functions for a lattice determination are presented. In contrast, the excited states contamination of one of the semileptonic form factors is an order of magnitude larger and negative.