Abstract
We consider supersymmetric grand unified theories with soft supersymmetry-breaking scalar masses m_0 specified above the GUT scale (super-GUTs) and patterns of Yukawa couplings motivated by upper limits on flavour-changing interactions beyond the Standard Model. If the scalar masses are smaller than the gaugino masses m_{1/2}, as is expected in no-scale models, the dominant effects of renormalisation between the input scale and the GUT scale are generally expected to be those due to the gauge couplings, which are proportional to m_{1/2} and generation independent. In this case, the input scalar masses m_0 may violate flavour maximally, a scenario we call MaxSFV, and there is no supersymmetric flavour problem. We illustrate this possibility within various specific super-GUT scenarios that are deformations of no-scale gravity.
Highlights
A suitable framework for studying the supersymmetric flavour problem is provided by a supersymmetric GUT such as SU(5) [6,7] in which the soft supersymmetry-breaking scalar masses m0, the trilinear soft supersymmetry-breaking parameters A0 and the gaugino masses m1/2 are input at the GUT scale MGUT 1016 GeV
We consider supersymmetric grand unified theories with soft supersymmetry-breaking scalar masses m0 specified above the GUT scale and patterns of Yukawa couplings motivated by upper limits on flavourchanging interactions beyond the Standard Model
Upper limits on the deviations from Standard Model predictions for flavour-changing processes motivate the hypothesis that the m0 parameters for chiral supermultiplets with the same gauge quantum numbers are identical at this input scale [2], and the GUT symmetry requires them to be identical for all the sparticles in the same GUT multiplet
Summary
A suitable framework for studying the supersymmetric flavour problem is provided by a supersymmetric GUT such as SU(5) [6,7] in which the soft supersymmetry-breaking scalar masses m0, the trilinear soft supersymmetry-breaking parameters A0 and the gaugino masses m1/2 are input at the GUT scale MGUT 1016 GeV. It is clear that the constraints on the non-universalities between the diagonal m0 parameters and on the ratios of off-diagonal to diagonal entries in the soft supersymmetry-breaking scalar mass matrix must become progressively weaker as the noscale limit: m0 → 0 is approached Close to this no-scale limit a completely anarchic m0 matrix is allowed. We use weak-scale measurements to specify the gauge and Yukawa couplings, whereas the soft supersymmetry-breaking scalar masses, trilinear and bilinear terms are specified at the input scale, Min. The matching conditions at MGUT are discussed in Sect. 3 we analyse the case of pure no-scale boundary conditions, in which all soft supersymmetry-breaking scalar masses, trilinear and bilinear terms are set to zero at Min. We display the running of these parameters as well as the Yukawa couplings between the input and weak scales for our representative flavour-mixing scenarios.
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