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Désintégration des mésons B. Méthodes d'extraction des angles décrivant la violation de CP. Théorie effective des facteurs de forme lourd à léger.

Abstract : This thesis, which is divided into two parts, presents a study of the weak interaction of heavy quarks. The aim is to help determine the fundamental parameters of the Cabibbo-Kobayashi-Maskawa mixing matrix, but also to bring an insight into the hadronic structure. The theoretical problems concerning CP-violation that may affect the extraction of the angles of the Unitarity Triangle are handled with. A first aspect is related to the hadronic uncertainties due to the penguin contributions. As for the decay B -> pi+pi-, an exact and simple description of these effects is proposed in terms of a single parameter, which may be constrained by phenomenological means. A second aspect concerns the discrete ambiguities on the CP angles and the phase space analyses which allow to lift them: the invariant mass distribution of events for the decays into three pseudoscalar mesons, and the angular distribution for the decays into hyperon and antihyperon. In the second part of the thesis, the form factors that describe the heavy-to-light transitions such as B -> pi(rho) l nu, B -> K* gamma et B -> K(*) l+l- are studied within an effective field theory framework ; they are at the core of the determination of, e.g., |Vub| et |Vts|. In the heavy mass and final hadron large energy limit and neglecting radiative corrections, it is shown that only three independent form factors describe the matrix elements B -> P and B -> V, where P (V) stands for a pseudoscalar (vector) meson which should be light with respect to the B. Moreover, the dependence of these form factors with respect to the heavy mass M and large energy E may be factorized as sqrt{M} x z(E), and one expects more specifically a sqrt{M} / E^2 behaviour. These predictions, that hold to leading order in 1/M, 1/E and alpha_s, are satisfied exactly by the QCD sum rules on the light-cone, and by a particular covariant class of constituent quark models, constructed according to the Bakamjian-Thomas formalism.
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https://tel.archives-ouvertes.fr/tel-00002502
Contributor : Jérôme Charles <>
Submitted on : Tuesday, March 4, 2003 - 9:48:41 AM
Last modification on : Wednesday, December 9, 2020 - 10:48:07 AM
Long-term archiving on: : Tuesday, September 11, 2012 - 8:00:28 PM

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  • HAL Id : tel-00002502, version 1

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Jérôme Charles. Désintégration des mésons B. Méthodes d'extraction des angles décrivant la violation de CP. Théorie effective des facteurs de forme lourd à léger.. Physique des Hautes Energies - Expérience [hep-ex]. Université Paris Sud - Paris XI, 1999. Français. ⟨tel-00002502⟩

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