We update the constraints on new-physics contributions to Delta F = 2 processes from the generalized unitarity triangle analysis, including the most recent experimental developments. Based on these constraints, we derive upper bounds on the coefficients of the most general Delta F = 2 effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of new physics that contributes to these low-energy effective interactions. We point out that, due to the enhancement in the renormalization group evolution and in the matrix elements, the coefficients of non-standard operators are much more constrained than the coefficient of the operator present in the Standard Model. Therefore, the scale of new physics in models that generate new Delta F = 2 operators, such as next-to-minimal flavour violation, has to be much higher than the scale of minimal flavour violation, and it most probably lies beyond the reach of direct searches at the LHC.
|Titolo:||Model-independent constraints on Delta F=2 operators and the scale of new physics|
|Autori:||M. Bona; M. Ciuchini; E. Franco; V. Lubicz; Guido Martinelli; F. Parodi; M. Pierini; P. Roudeau; C. Schiavi; L. Silvestrini; V. Sordini; A. Stocchi; V. Vagnoni; Utfit Collaboration|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||10.1088/1126-6708/2008/03/049|
|Appare nelle tipologie:||1.1 Journal article|