A Domino Theory of Flavor

We argue that the fermion masses and mixings are organized in a specific pattern. The approximately equal hierarchies between successive generations, the sizes of the mixing angles, the heaviness of just the top quark, and the approximate down-lepton equality can all be accommodated by many flavor models but can appear ad hoc. We present a simple, predictive mechanism to explain these patterns. All generations are treated democratically and the flavor symmetries are broken collectively by only two allowed couplings in flavor-space, a vector and matrix, with arbitrary O(1) entries. Repeated use of these flavor symmetry breaking spurions radiatively generates the Yukawa couplings with a natural hierarchy. We demonstrate this idea with two models in a split supersymmetric grand unified framework, with minimal additional particle content at the unification scale. Although flavor is generated at the GUT scale, there are several potentially testable predictions. In our minimal model the usual prediction of exact b-tau unification is replaced by the SU(5) breaking relation m_tau / m_b = 3 / 2, in better agreement with observations. Other SU(5) breaking effects in the fermion masses can easily arise directly from the flavor model itself. The symmetry breaking that triggers the generation of flavor necessarily gives rise to an axion, solving the strong CP problem. These theories contain long-lived particles whose decays could give striking signatures at the LHC and may solve the primordial Lithium problems. These models also give novel proton decay signatures which can be probed by the next generation of experiments. Measurement of the various proton decay channels directly probes the flavor symmetry breaking couplings. In this scenario the Higgs mass is predicted to lie in a range near 150 GeV.Comment: 33 pages, 11 figures, 5 tables. v2: Refs added, version to appear in PR

Axion Isocurvature and Magnetic Monopoles

We propose a simple mechanism to suppress axion isocurvature fluctuations using hidden sector magnetic monopoles. This allows for the Peccei-Quinn scale to be of order the unification scale consistently with high scale inflation.Comment: 13 page

A Composite Solution to the Neutron Bottle Anomaly

Measurements of the lifetime of neutrons trapped in a bottle have been consistently shorter than the lifetime measured in neutron beam experiments. With trapping potentials as low as 50 neV and neutron detectors located only at the top of the bottle, this discrepancy could be the result of the soft scattering of dark matter with neutrons. However, it is challenging to obtain the observed loss rate in conventional models of dark matter scattering. We show that this phenomenology is possible in composite models of dark matter where the soft scattering is from dark matter that has been captured and accumulated in the earth. This solution can be tested by placing more neutron detectors around the trap, providing better angular coverage. The phenomenology of soft scattering by trapped composite dark matter is generic and suggests new experimental directions that could be pursued to detect this large class of models.Comment: 11 pages and 2 figure