RGE Behaviour of SUSY with a U(2)^3 symmetry

TL;DR

This paper investigates the renormalization group evolution of a U(2)^3 flavor symmetry in split-family SUSY models, analyzing low-energy implications, flavor violation operators, and potential extensions to the lepton sector.

Contribution

It provides a detailed RGE analysis of U(2)^3 symmetry breaking in split-family SUSY, including operator effects and extensions to leptons, which is novel in flavor symmetry studies.

Findings

U(2)^3 breaking can be consistent with high-scale boundary conditions

(LL)(RR) operators are significant due to LHC gluino bounds

Possible U(2)^3 extension to the lepton sector is explored

Abstract

The first LHC results seem to disfavour, from the point of view of naturalness, any constrained MSSM realization with universal conditions at the SUSY-breaking scale. A more motivated scenario is given by split-family SUSY, in which the first two generations of squarks are heavy, compatible with a U(2)^3 flavour symmetry. We consider this flavour symmetry to be broken at a very high scale and study the consequences at low energies through its RGE evolution. Initial conditions compatible with a split scenario are found, and the preservation of correlations from minimal U(2)^3 breaking are checked. The various chiral operators in $\Delta F=2$ processes are analyzed, and we show that, due to LHC gluino bounds, the (LL)(RR) operators can not always be neglected. Finally, we also study a possible extension of the U(2)^3 model compatible with the lepton sector.