100, rue des maths 38610 Gières / GPS : 45.193055, 5.772076 / Directeur : Thierry Gallay

Le bâtiment de l'Institut Fourier est à nouveau accessible par badge ou code, de 6h30 à 21h30, du lundi au vendredi. Il reste toutefois fermé et sous alarme les week-ends et jours fériés. La bibliothèque du laboratoire est actuellement fermée, mais un service de prêt et de retour d'ouvrages a été mis en place. La cafétéria du second étage est en travaux, pour une longue période. Pour des raisons de traçabilité, les membres du laboratoire sont priés de signaler leurs jours de présence en remplissant le sondage envoyé par la direction. Pour de plus amples informations, consulter l'intranet du laboratoire.
 
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Benjamin Alvarez

An introduction to quantum field theory and of scattering theory. Application to the decay of the W bosons.
Mercredi, 17 Avril, 2019 - 17:00 à 18:00
Résumé : 

The decay of the W bosons into the full family of leptons can be modeled by an unbounded self-adjoint operator acting on a Hilbert space of Fock type. The allowed energy values of the physical system are in the spectrum of this operator which is divided in three parts: the absolutely continuous spectrum, the singular continuous spectrum and the eigenvalues. The subspace related to the absolutely continuous part gathers the scattered states which are located far from the experiment center. As time goes to infinity, it would be expected that they behave like if there were not any interaction. Mathematically, this intuition is expressed through the notion of asymptotic completeness of the wave operators. Moreover, the idea behind a particle physics experiment is to detect an out-coming scattered states knowing the in-coming scattered states. The mathematical object which relates these particles is the so-called scattering matrix. One of the goals of a scattering theory is to prove the existence of the scattering matrix and the property of asymptotic completeness. In this presentation we will give a pedagogical introduction to all these notions through the example of the weak decay of the W ± bosons into the full family of leptons.

Institution de l'orateur : 
Université de Lorraine
Thème de recherche : 
Compréhensible
Salle : 
4
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