A Couplet from Flavored Dark Matter

We show that a couplet, a pair of closely spaced photon lines, in the X-ray spectrum is a distinctive feature of lepton flavored dark matter models for which the mass spectrum is dictated by Minimal Flavor Violation. In such a scenario, mass splittings between different dark matter flavors are determined by Standard Model Yukawa couplings and can naturally be small, allowing all three flavors to be long-lived and contribute to the observed abundance. Then, in the presence of a tiny source of flavor violation, heavier dark matter flavors can decay via a dipole transition on cosmological timescales, giving rise to three photon lines. The ratios of the line energies are completely determined in terms of the charged lepton masses, and constitute a firm prediction of this framework. For dark matter masses of order the weak scale, the couplet lies in the keV-MeV region, with a much weaker line in the eV-keV region. This scenario constitutes a potential explanation for the recent claim of the observation of a 3.5 keV line. The next generation of X-ray telescopes may have the necessary resolution to resolve the double line structure of such a couplet.Comment: 17 pages, 4 figures, 1 haik

Detecting Dark Matter with Aharonov-Bohm

While the evidence for dark matter continues to grow, the nature of the dark matter remains a mystery. A dark $U(1)_D$ gauge theory can have a small kinetic mixing with the visible photon which provides a portal to the dark sector. Magnetic monopoles of the dark $U(1)_D$ can obtain small magnetic couplings to our photon through this kinetic mixing. This coupling is only manifest below the mass of the dark photon; at these scales the monopoles are bound together by tubes of dark magnetic flux. These flux tubes can produce phase shifts in Aharonov-Bohm type experiments. We outline how this scenario might be realized, examine the existing constraints, and quantify the experimental sensitivity required to detect magnetic dipole dark matter in this novel way.Comment: 14 pages, 2 figures; Updated references and expanded discussion agrees with published versio

Interactions of a Stabilized Radion and Duality

We determine the couplings of the graviscalar radion in Randall-Sundrum models to Standard Model fields propagating in the bulk of the space, taking into account effects arising from the dynamics of the Goldberger-Wise scalar that stabilizes the size of the extra dimension. The leading corrections to the radion couplings are shown to arise from direct contact interactions between the Goldberger-Wise scalar and the Standard Model fields. We obtain a detailed interpretation of the results in terms of the holographic dual of the radion, the dilaton. In doing so, we determine how the familiar identification of the parameters on the two sides of the AdS/CFT correspondence is modified in the presence of couplings of the bulk Standard Model fields to the Goldberger-Wise scalar. We find that corrections to the form of the dilaton couplings from effects associated with the stabilization of the extra dimension are suppressed by the square of the ratio of the dilaton mass to the Kaluza-Klein scale, in good agreement with results from the CFT side of the correspondence.Comment: 22 pages plus appendices and reference