0000000000450505
AUTHOR
Vicent Mateu Barreda
Oriented event shapes at (NLL)-L-3 + O(alpha(2)(S))
We analyze oriented event-shapes in the context of Soft-Collinear Effective Theory (SCET) and in fixed-order perturbation theory. Oriented event-shapes are distributions of event-shape variables which are differential on the angle theta(T) that the thrust axis forms with the electron-positron beam. We show that at any order in perturbation theory and for any event shape, only two angular structures can appear: F-0 = 3/8 (1+cos(2) theta(T)) and F-1 = (1 ¿ 3 cos(2) theta(T)). When integrating over theta(T) to recover the more familiar event-shape distributions, only F-0 survives. The validity of our proof goes beyond perturbation theory, and hence only these two structures are present at the …
Aplicacions de mètodes no pertorbatius a la dinàmica del sabor
RESUMEN A día de hoy, el Modelo Estándar de las interacciones electrodébiles describe correctamente todos los fenómenos observados en la naturaleza. Sin embargo no proporciona ninguna explicación al hecho de que existan tres familias fermiónicas, incluyendo cada una quarks y leptones. Estas familias se distinguen por el grado de libertad sabor. Debido a la ruptura espontánea de la simetría local gauge, existe un patrón de sabor muy rico. En particular, las partículas tienen masas diferentes, y las diversas familias se mezclan (en el caso de los quarks) cuando interaccionan con los bosones mediadores. El conocimiento preciso de las masas y ángulos de mezcla de los quarks es fundamental para …
Boosted objects and jet substructure at the LHC
This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of first-principle QCD calculations to yield a precise description of the substructure of jets and study the accuracy of state-of-the-art Monte Carlo tools. Limitations of the experiments' ability to resolve substructure are evaluated, with a focus on the impact of additional (pile-up) proton proton collisions on jet substructure performance in future LHC operating scenarios. A final section summarizes the lessons learnt from jet substructure analyses in searches for new physics in the production of boosted top quarks.