Viable gravity-mediated supersymmetry breaking
Citations Over TimeTop 10% of 2010 papers
Abstract
We present a complete, viable model of gravity-mediated supersymmetry breaking that is safe from all flavor constraints. The central new idea is to employ a supersymmetry breaking sector without singlets, but with $D$-terms comparable to $F$-terms, causing supersymmetry breaking to be dominantly communicated through $\mathrm{U}(1{)}_{R}$-symmetric operators. We construct a visible sector that is an extension of the minimal supersymmetric standard model where an accidental $\mathrm{U}(1{)}_{R}$-symmetry emerges naturally. Gauginos acquire Dirac masses from gravity-mediated $D$-terms and tiny Majorana masses from anomaly-mediated contributions. Contributions to soft breaking scalar $(\mathrm{mass}{)}^{2}$ arise from flavor-arbitrary gravity-induced $F$-terms plus one-loop finite flavor-blind contributions from Dirac gaugino masses. Renormalization group evolution of the gluino causes it to naturally increase nearly an order of magnitude larger than the squark masses. This hierarchy, combined with an accidentally $\mathrm{U}(1{)}_{R}$-symmetric visible sector, nearly eliminates all flavor violation constraints on the model. If we also freely tune couplings and phases within the modest range 0.1--1, while maintaining nearly flavor-anarchic Planck-suppression contributions, we find our model to be safe from $\ensuremath{\Delta}{m}_{K}$, ${ϵ}_{K}$, and $\ensuremath{\mu}\ensuremath{\rightarrow}e$ lepton flavor violation. Dangerous $\mathrm{U}(1{)}_{R}$-violating K\"ahler operators in the Higgs sector are eliminated through a new gauged $\mathrm{U}(1{)}_{X}$ symmetry that is spontaneously broken with electroweak symmetry breaking. Kinetic mixing between $\mathrm{U}(1{)}_{X}$ and $\mathrm{U}(1{)}_{Y}$ is present with loop-suppressed (but log-enhanced) size $ϵ$. The ${Z}^{\ensuremath{'}}$ associated with this $\mathrm{U}(1{)}_{X}$ has very peculiar couplings---it has order one strength to Higgs doublets and approximately $ϵ$ strength to hypercharge. The ${Z}^{\ensuremath{'}}$ could be remarkably light and yet have escaped direct and indirect detection.