282 research outputs found

    Electroweak symmetry breaking and cold dark matter from hidden sector technicolor

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    We consider models with a vectorlike confining gauge theory in the hidden sector, and demonstrate that the origin of the electroweak symmetry breaking (EWSB) is due to the dimensional transmutation in the hidden sector gauge theory, and the lightest mesons in the hidden sector could be a good cold dark matter (CDM) candidate. There would be more than one neutral Higgs-like scalar bosons, and they could decay mainly into the CDM pair, if that decay channel is kinemtically allowed.Comment: To appear in the proceeding of the 4th International Conference on Flavor Physic

    A simple modification of the maximal mixing scenario for three light neutrinos

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    We suggest a simple modification of the maximal mixing scenario (with S3S_3 permutation symmetry) for three light neutrinos. Our neutrino mass matrix has smaller permutation symmetry S2S_{2} (νμνe\nu_{\mu} \leftrightarrow \nu_{e}), and is consistent with all neutrino experiments except the 37^{37}Cl experiment. The resulting mass eigenvalues for three neutrinos are m1(2.551.27)×103eV,m2,3(0.711.43)eVm_{1} \approx (2.55-1.27) \times 10^{-3} eV, m_{2,3} \approx (0.71-1.43) eV for ΔmLSND2=0.52.0eV2\Delta m_{LSND}^{2} = 0.5 - 2.0 eV^2. Then these light neutrinos can account for (2.44.8)\sim (2.4-4.8)% (6.2-12.4 %) of the dark matter for h=0.8(0.5)h = 0.8 (0.5). Our model predicts the νμντ\nu_{\mu} \rightarrow \nu_{\tau} oscillation probability in the range sensitive to the future experiments such as CHORUS and NOMAD.Comment: The title has been changed, to appear in Z. Phys.

    Sflavor mixing map viewed from a high scale in supersymmetric SU(5)

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    We study flavor violation in a supersymmetric SU(5) grand unification scenario in a model-independent way employing mass insertions. We examine how the quark and the lepton sector observables restrict sfermion mixings. With a low soft scalar mass, a lepton flavor violating process provides a stringent constraint on the flavor structure of right-handed down-type squarks. In particular, mu -> e gamma turns out to be highly susceptible to the 1-3 and 2-3 mixings thereof, due to the radiative correction from the top Yukawa coupling to the scalar mass terms of 10. With a higher scalar mass around the optimal value, in contrast, the quark sector inputs such as B-meson mixings and hadron electric dipole moment, essentially determine the room for sfermion mixing. We also discuss the recent deviation observed in B_s mixing phase, projected sensitivity of forthcoming experiments, and ways to maintain the power of leptonic restrictions even after incorporating a solution to fix the incorrect quark-lepton mass relations.Comment: 40 pages, updated using phi_s from HFAG, conclusion unchange

    Metastable supersymmetry breaking vacua from conformal dynamics

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    We study the scenario that conformal dynamics leads to metastable supersymmetry breaking vacua. At a high energy scale, the superpotential is not R-symmetric, and has a supersymmetric minimum. However, conformal dynamics suppresses several operators along renormalization group flow toward the infrared fixed point. Then we can find an approximately R-symmetric superpotential, which has a metastable supersymmetry breaking vacuum, and the supersymmetric vacuum moves far away from the metastable supersymmetry breaking vacuum. We show a 4D simple model. Furthermore, we can construct 5D models with the same behavior, because of the AdS/CFT dual.Comment: 3 pages; Talk given at SUSY0

    Orbifold SUSY GUT from the Heterotic String

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    From the string partition function, we discuss the mass-shell and GSO projection conditions valid for Kaluza-Klein (KK) as well as massless states in the heterotic string theory compactified on a nonprime orbifold. Based on the obtained conditions we construct a 4D string standard model, which is embedded in a 6D SUSY GUT by including KK states above the compactification scale. We discuss the stringy threshold corrections to gauge couplings, including the Wilson line effects.Comment: To appear in the SUSY08 proceedings, 3 pages, LaTE

    Indirect Signatures of Gravitino Dark Matter

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    Supersymmetric models provide very interesting scenarios to account for the dark matter of the Universe. In this talk we discuss scenarios with gravitino dark matter in R-parity breaking vacua, which not only reproduce very naturally the observed dark matter relic density, but also lead to a thermal history of the Universe consistent with the observed abundances of primordial elements and the observed matter-antimatter asymmetry. In this class of scenarios the dark matter gravitinos are no longer stable, but decay with very long lifetimes into Standard Model particles, thus opening the possibility of their indirect detection. We have computed the expected contribution from gravitino decay to the primary cosmic rays and we have found that a gravitino with a mass of 150 GeV and a lifetime of 10^26 s could simultaneously explain the EGRET anomaly in the extragalactic gamma-ray background and the HEAT excess in the positron fraction.Comment: 6 pages, 4 figures. To appear in the proceedings of SUSY08, Seoul, Kore

    Sequestering in models of F-term uplifting

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    We discuss the nature of sequestering supersymmetry breaking sectors in a certain class of moduli stabilization in supergravity/string models, where a negative vacuum energy of the nonperturbative moduli potential is canceled by dynamically generated F-terms. Two illustrating examples are shown to sketch the issues around the supersymmetry breaking, flavors and sequestering within such a framework.Comment: 6 pages, no figure; Talks given at PASCOS08 (the 14th International Symposium on Particles, Strings and Cosmology, Waterloo, Canada, June 2-6, 2008) and SUSY08 (the 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions, Seoul, Korea, June 16-21, 2008

    Aspects of Unparticle Physics

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    We review some theoretical and experimental issues in unparticle physics, focusing mainly on collider signatures.Comment: 4 pages, latex. Based on talk at ICHEP0
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