201 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} (νμ↔νe\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≈(2.55−1.27)×10−3eV,m2,3≈(0.71−1.43)eVm_{1} \approx (2.55-1.27) \times 10^{-3} eV, m_{2,3} \approx (0.71-1.43) eV for ΔmLSND2=0.5−2.0eV2\Delta m_{LSND}^{2} = 0.5 - 2.0 eV^2. Then these light neutrinos can account for ∼(2.4−4.8)\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 νμ→ντ\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.

    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

    Modulated Inflation (@SUSY08)

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    We consider cosmological perturbations caused by modulated inflaton velocity. During inflation, the inflaton motion is damped and the velocity is determined by the parameters such as couplings or masses that may depend on light fields(moduli). The number of e-foldings is different in different patches if there are spatial fluctuations of such parameters. Based on this simple idea, we consider ``modulated inflation'' in which the curvature perturbation is generated by the fluctuation of the inflaton velocity. This talk is based on our recent papers.Comment: talk given at susy0

    An alternative to the standard model

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    We present an extension of the standard model to dark sector with an unbroken local dark U(1)XU(1)_X symmetry. Including various singlet portal interactions provided by the standard model Higgs, right-handed neutrinos and kinetic mixing, we show that the model can address most of phenomenological issues (inflation, neutrino mass and mixing, baryon number asymmetry, dark matter, direct/indirect dark matter searches, some scale scale puzzles of the standard collisionless cold dark matter, vacuum stability of the standard model Higgs potential, dark radiation) and be regarded as an alternative to the standard model. The Higgs signal strength is equal to one as in the standard model for unbroken U(1)XU(1)_X case with a scalar dark matter, but it could be less than one independent of decay channels if the dark matter is a dark sector fermion or if U(1)XU(1)_X is spontaneously broken, because of a mixing with a new neutral scalar boson in the models.Comment: 10 pages, 3 figures, VII International Conference on Interconnections between Particle Physics and Cosmology (PPC2013
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