Model-independent constraints on Delta F=2 operators and the scale of New Physics

Abstract

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.

Comments: 32 pages, 11 figures, 6 tables. v2: error in the implementation of D0 untagged Bs->J/Psi phi correlation matrix corrected. Improved presentation of the results and discussion of ambiguities in untagged Bs->J/Psi phi. Results for NP in Bs oscillations changed. Final version to appear in JHEP