Lightest-neutralino decays in R_p-violating models with dominant lambda^{prime} and lambda couplings

Decays of the lightest neutralino are studied in R_p-violating models with operators lambda^{prime} L Q D^c and lambda L L E^c involving third-generation matter fields and with dominant lambda^{prime} and lambda couplings. Generalizations to decays of the lightest neutralino induced by subdominant lambda^{prime} and lambda couplings are straightforward. Decays with the top-quark among the particles produced are considered, in addition to those with an almost massless final state. Phenomenological analyses for examples of both classes of decays are presented. No specific assumption on the composition of the lightest neutralino is made, and the formulae listed here can be easily generalized to study decays of heavier neutralinos. It has been recently pointed out that, for a sizable coupling lambda^{prime}_{333}, tau-sleptons may be copiously produced at the LHC as single supersymmetric particles, in association with top- and bottom-quark pairs. This analysis of neutralino decays is, therefore, a first step towards the reconstruction of the complete final state produced in this case.Comment: 40 pages, 11 figures, version to appear in JHE

Kaluza-Klein Dark Matter, Electrons and Gamma Ray Telescopes

Kaluza-Klein dark matter particles can annihilate efficiently into electron-positron pairs, providing a discrete feature (a sharp edge) in the cosmic $e^+ e^-$ spectrum at an energy equal to the particle's mass (typically several hundred GeV to one TeV). Although this feature is probably beyond the reach of satellite or balloon-based cosmic ray experiments (those that distinguish the charge and mass of the primary particle), gamma ray telescopes may provide an alternative detection method. Designed to observe very high-energy gamma-rays, ACTs also observe the diffuse flux of electron-induced electromagnetic showers. The GLAST satellite, designed for gamma ray astronomy, will also observe any high energy showers (several hundred GeV and above) in its calorimeter. We show that high-significance detections of an electron-positron feature from Kaluza-Klein dark matter annihilations are possible with GLAST, and also with ACTs such as HESS, VERITAS or MAGIC.Comment: 10 pages, 2 figure

Determining Supersymmetric Parameters With Dark Matter Experiments

In this article, we explore the ability of direct and indirect dark matter experiments to not only detect neutralino dark matter, but to constrain and measure the parameters of supersymmetry. In particular, we explore the relationship between the phenomenological quantities relevant to dark matter experiments, such as the neutralino annihilation and elastic scattering cross sections, and the underlying characteristics of the supersymmetric model, such as the values of mu (and the composition of the lightest neutralino), m_A and tan beta. We explore a broad range of supersymmetric models and then focus on a smaller set of benchmark models. We find that by combining astrophysical observations with collider measurements, mu can often be constrained far more tightly than it can be from LHC data alone. In models in the A-funnel region of parameter space, we find that dark matter experiments can potentially determine m_A to roughly +/-100 GeV, even when heavy neutral MSSM Higgs bosons (A, H_1) cannot be observed at the LHC. The information provided by astrophysical experiments is often highly complementary to the information most easily ascertained at colliders.Comment: 46 pages, 76 figure

The Muon Magnetic Moment and Supersymmetry

The present review is devoted to the muon magnetic moment and its role in supersymmetry phenomenology. Analytical results for the leading supersymmetric one- and two-loop contributions are provided, numerical examples are given and the dominant tan(beta)sign(mu)/M_SUSY^2 behaviour is qualitatively explained. The consequences of the Brookhaven measurement are discussed. The 2 sigma deviation from the Standard Model prediction implies preferred ranges for supersymmetry parameters, in particular upper and lower mass bounds. Correlations with other observables from collider physics and cosmology are reviewed. We give, wherever possible, an intuitive understanding of each result before providing a detailed discussion.Comment: Topical Review; 54 pages, 18 figure