Direct Detection of Non-Chiral Dark Matter

Direct detection experiments rule out fermion dark matter that is a chiral representation of the electroweak gauge group. Non-chiral real, complex and singlet representations, however, provide viable fermion dark matter candidates. Although any one of these candidates will be virtually impossible to detect at the LHC, it is shown that they may be detected at future planned direct detection experiments. For the real case, an irreducible radiative coupling to quarks may allow a detection. The complex case in general has an experimentally ruled out tree-level coupling to quarks via Z-boson exchange. However, in the case of two SU(2)_L doublets, a higher dimensional coupling to the Higgs can suppress this coupling, and a remaining irreducible radiative coupling may allow a detection. Singlet dark matter could be detected through a coupling to quarks via Higgs exchange. Since all non-chiral dark matter can have a coupling to the Higgs, at least some of its mass can be obtained from electroweak symmetry breaking, and this mass is a useful characterization of its direct detection cross-section.Comment: 22 pages, 3 figures. References added. Minor corrections to match published versio

Light dark forces at flavor factories

SuperB experiment could represent an ideal environment to test a new U (1) symmetry related to light dark forces candidates. A promising discovery channel is represented by the resonant production of a boson U, followed by its decay into lepton pairs. Beyond approximations adopted in the literature, an exact tree level calculation of the radiative processes $e+ e- \rightarrow \gamma, U \rightarrow \mu^+ \mu^- \gamma, e^+ e^- \gamma$ and corresponding QED backgrounds is performed, including also the most important higher-order corrections. The calculation is implemented in a release of the generator BabaYaga@NLO useful for data analysis and interpretation. The distinct features of U boson production are shown and the statistical significance is analysed

Notes on SUSY and R-Symmetry Breaking in Wess-Zumino Models

We study aspects of Wess-Zumino models related to SUSY and R-symmetry breaking at tree-level. We present a recipe for constructing a wide class of tree-level SUSY and R-breaking models. We also deduce a general property shared by all tree-level SUSY breaking models that has broad application to model building. In particular, it explains why many models of direct gauge mediation have anomalously light gauginos (even if the R-symmetry is broken spontaneously by an order one amount). This suggests new approaches to dynamical SUSY breaking which can generate large enough gaugino masses.Comment: 23 pages. v2: references added, minor changes. v3: comment on non-renormalizable case adde

On the Thermal History of Calculable Gauge Mediation

Many messenger models with realistic gaugino masses are based on meta-stable vacua. In this work we study the thermal history of some of these models. Analyzing R-symmetric models, we point out that while some of the known messenger models clearly prefer the supersymmetric vacuum, there is a vast class of models where the answer depends on the initial conditions. Along with the vacuum at the origin, the high temperature thermal potential also possesses a local minimum far away from the origin. This vacuum has no analog at zero temperature. The first order phase transition from this vacuum into the supersymmetric vacuum is parametrically suppressed, and the theory, starting from that vacuum, is likely to evolve to the desired gauge-mediation vacuum. We also comment on the thermal evolution of models without R-symmetry.Comment: 22 pages. V2: Comments on the SM effects added. Minor corrections. Reference added. Valuable discussion with S. Abel, J. Jaeckel and V. Khoze acknowledged. V3: Types of EOGM explicitly defined in the introduction. Discussions about the phase transitions expanded. Typo corrected. Journal versio

Two Loop R-Symmetry Breaking

We analyze two loop quantum corrections for pseudomoduli in O'Raifeartaigh like models. We argue that R-symmetry can be spontaneously broken at two loop in non supersymmetric vacua. We provide a basic example with this property. We discuss on phenomenological applications.Comment: 13 pages, 5 figures, JHEP3.cls, reference adde

A Hybrid Higgs

We construct composite Higgs models admitting a weakly coupled Seiberg dual description. We focus on the possibility that only the up-type Higgs is an elementary field, while the down-type Higgs arises as a composite hadron. The model, based on a confining SQCD theory, breaks supersymmetry and electroweak symmetry dynamically and calculably. This simultaneously solves the \mu/B_\mu problem and explains the smallness of the bottom and tau masses compared to the top mass. The proposal is then applied to a class of models where the same confining dynamics is used to generate the Standard Model flavor hierarchy by quark and lepton compositeness. This provides a unified framework for flavor, supersymmetry breaking and electroweak physics. The weakly coupled dual is used to explicitly compute the MSSM parameters in terms of a few microscopic couplings, giving interesting relations between the electroweak and soft parameters. The RG evolution down to the TeV scale is obtained and salient phenomenological predictions of this class of "single-sector" models are discussed.Comment: 56 pages, 7 figures, v2: discussion on FCNCs and references added, v3: JHEP versio