890 research outputs found

    Dark Matter in Universal Extra Dimension Models: γKK\gamma_{KK} vrs νR,KK\nu_{R,KK}

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    We show that in a class of universal extra dimension models (UED), which solves both the neutrino mass and proton decay problem, an admixture of KK photon and KK right handed neutrinos can provide the required amount of cold dark matter (CDM). This model has two parameters R−1R^{-1} and MZ′M_{Z'} (RR is the radius of the extra space dimensions and Z′Z' the extra neutral gauge boson of the model). Using the value of the relic CDM density, combined with the results from the cryogenic searches for CDM, we obtain upper limits on R−1R^{-1} of about 400-650 GeV and MZ′≤1.5M_{Z'}\leq 1.5 TeV, both being accessible to LHC. In some regions of the parameter space, the dark matter-nucleon scattering cross section can be as high as of 10−4410^{-44} cm2^2, which can be probed by the next round of dark matter search experiments.Comment: 13 pages, 2 figures; minor changes; to appear in Phys. Rev.

    Unified TeV Scale Picture of Baryogenesis and Dark Matter

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    We present a simple extension of MSSM which provides a unified picture of cosmological baryon asymmetry and dark matter. Our model introduces a gauge singlet field NN and a color triplet field XX which couple to the right--handed quark fields. The out--of equilibrium decay of the Majorana fermion NN mediated by the exchange of the scalar field XX generates adequate baryon asymmetry for MN∼100M_N \sim 100 GeV and MX∼M_X \sim TeV. The scalar partner of NN (denoted N~1\tilde{N}_1) is naturally the lightest SUSY particle as it has no gauge interactions and plays the role of dark matter. N~1\tilde{N}_1 annihilates into quarks efficiently in the early universe via the exchange of the fermionic X~\tilde{X} field. The model is experimentally testable in (i) neutron--antineutron oscillations with a transition time estimated to be around 101010^{10} sec, (ii) discovery of colored particles XX at LHC with mass of order TeV, and (iii) direct dark matter detection with a predicted cross section in the observable range.Comment: 10 pages, one reference updated. Version to appear in Phys. Rev. Let

    Kinerja Portofolio Saham pada Perusahaan Makanan, Property dan Pertambangan di Bursa Efek Indonesia

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    The Stock Portfolios' Performance of Food, Property, and Mining IndustryThis research aimed to analyze the Portfolio's performance of food industry, property, and mining. There are three parameters, namely: Sharpe Performance, Traynor Performance, and Jensen Performance. The three performance measurements assume that there is a linear connection between the return portfolios with the return of some market index. During the period, 2009 to 2013, and the mining and gas sub-sector are more productive than the other sub-sectors. The mining sector is better than the Property Sector and the Food Sector. Then based on the method of Jensen ALPHA it showed the highest performance group of mining stocks, in proportion to the risk which is also very high. The study suggests that the existing has to be maintained and further improved so that the mission to develop sources of potential energy into a profitable investment portfolio can sustain.DOI: 10.15408/ess.v7i2.535

    Neutrino Mixing and Leptogenesis in μ−τ\mu-\tau Symmetry

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    We study the consequences of the Z2Z_2-symmetry behind the μ\mu--τ\tau universality in neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass hierarchies and generate enough lepton asymmetry to interpret the observed baryon asymmetry in the universe. We also show how a specific form of a high-scale perturbation is kept when translated via the seesaw into the low scale domain, where it can accommodate the neutrino mixing data. We finally present a realization of the high scale perturbed texture through addition of matter and extra exact symmetries.Comment: 29 pages, 1 figure, 3 tables. Complete re-analysis. Version to appear in PR

    Reconciling the CAST and PVLAS Results

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    The PVLAS experiment has recently claimed evidence for an axion-like particle in the milli-electron-Volt mass range with a coupling to two photons that appears to be in contradiction with the negative results of the CAST experiment searching for solar axions. The simple axion interpretation of these two experimental results is therefore untenable and it has posed a challenge for theory. We propose a possible way to reconcile these two results by postulating the existence of an ultralight pseudo-scalar particle interacting with two photons and a scalar boson and the existence of a low scale phase transition in the theory.Comment: 4 pages, 2 figures; references update
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