An Extension for Direct Gauge Mediation of Metastable Supersymmetry Breaking

We study the direct mediation of metastable supersymmetry breaking by a \Phi^2-deformation to the ISS model and extend it by splitting both Tr\Phi and Tr\Phi^2 terms in the superpotential and gauging the flavor symmetry. We find that with such an extension the enough long-lived metastable vacua can be obtained and the proper gaugino masses can be generated. Also, this allows for constructing a kind of models which can avoid the Landau pole problem. Especially, in our metastable vacua there exist a large region for the parameter m_3 which can satisfy the phenomenology requirements and allow for a low SUSY breaking scale (\sim 100 TeV).Comment: version in Europhys. Let

Lectures on Supersymmetry Breaking

We review the subject of spontaneous supersymmetry breaking. First we consider supersymmetry breaking in a semiclassical theory. We illustrate it with several examples, demonstrating different phenomena, including metastable supersymmetry breaking. Then we give a brief review of the dynamics of supersymmetric gauge theories. Finally, we use this dynamics to present various mechanisms for dynamical supersymmetry breaking. These notes are based on lectures given by the authors in 2007, at various schools.Comment: 47 pages. v2: minor correction

External Fields as a Probe for Fundamental Physics

Quantum vacuum experiments are becoming a flexible tool for investigating fundamental physics. They are particularly powerful for searching for new light but weakly interacting degrees of freedom and are thus complementary to accelerator-driven experiments. I review recent developments in this field, focusing on optical experiments in strong electromagnetic fields. In order to characterize potential optical signatures, I discuss various low-energy effective actions which parameterize the interaction of particle-physics candidates with optical photons and external electromagnetic fields. Experiments with an electromagnetized quantum vacuum and optical probes do not only have the potential to collect evidence for new physics, but special-purpose setups can also distinguish between different particle-physics scenarios and extract information about underlying microscopic properties.Comment: 12 pages, plenary talk at QFEXT07, Leipzig, September 200

Dark Matter Candidates: A Ten-Point Test

An extraordinarily rich zoo of non-baryonic Dark Matter candidates has been proposed over the last three decades. Here we present a 10-point test that a new particle has to pass, in order to be considered a viable DM candidate: I.) Does it match the appropriate relic density? II.) Is it {\it cold}? III.) Is it neutral? IV.) Is it consistent with BBN? V.) Does it leave stellar evolution unchanged? VI.) Is it compatible with constraints on self-interactions? VII.) Is it consistent with {\it direct} DM searches? VIII.) Is it compatible with gamma-ray constraints? IX.) Is it compatible with other astrophysical bounds? X.) Can it be probed experimentally?Comment: 29 pages, 12 figure

Searching Hidden-sector Photons inside a Superconducting Box.

We propose an experiment to search for extra "hidden-sector" U(1) gauge bosons with gauge kinetic mixing with the ordinary photon, predicted by many extensions of the Standard Model. The setup consists of a highly sensitive magnetometer inside a superconducting shielding. This is then placed inside a strong (but sub-critical) magnetic field. In ordinary electrodynamics the magnetic field cannot permeate the superconductor and no field should register on the magnetometer. However, photon -- hidden-sector photon -- photon oscillations would allow to penetrate the superconductor and the magnetic field would "leak" into the shielded volume and register on the magnetometer. Although this setup resembles a classic ``light shining though a wall experiment'' there are two crucial differences. First, the fields are (nearly) static and the photons involved are virtual. Second, the magnetometer directly measures the field-strength and not a probability. This improves the dependence of the signal on the kinetic mixing chi (\ll 1) to chi^2 instead of chi^4. For hidden photon masses in the range 0.002-200 meV the projected sensitivity for the mixing parameter lies in the 5 10^-9 to 10^-6 range. This surpasses current astrophysical and laboratory limits by several orders of magnitude -- ample room to discover new physics.Comment: 7 pages, 3 figure

Helioscope Bounds on Hidden Sector Photons.

The flux of hypothetical "hidden photons" from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to 10^-14, depending on the hidden photon mass. Furthermore, it is pointed out that helioscopes looking for solar axions are also very sensitive to hidden photons. The recent results of the CAST collaboration are used to further constrain the mixing parameter at low masses m<1 eV where the luminosity bound is weaker. In this regime the solar hidden photon flux has a sizable contribution of longitudinally polarized hidden photons of low energy which are invisible for current helioscopes.Comment: 25 pages, 8 figures; Minor comments and one figure added. Submitted to JCA