1,096 research outputs found

    Using Markov Models and Statistics to Learn, Extract, Fuse, and Detect Patterns in Raw Data

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    Many systems are partially stochastic in nature. We have derived data driven approaches for extracting stochastic state machines (Markov models) directly from observed data. This chapter provides an overview of our approach with numerous practical applications. We have used this approach for inferring shipping patterns, exploiting computer system side-channel information, and detecting botnet activities. For contrast, we include a related data-driven statistical inferencing approach that detects and localizes radiation sources.Comment: Accepted by 2017 International Symposium on Sensor Networks, Systems and Securit

    Flavon exchange effects in models with abelian flavor symmetry

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    In models with abelian flavor symmetry the small mixing angles and mass ratios of quarks and leptons are typically given by powers of small parameters characterizing the spontaneous breaking of flavor symmetry by "flavon" fields. If the scale of the breaking of flavor symmetry is near the weak scale, flavon exchange can lead to interesting flavor-violating and CP violating effects. These are studied. It is found that d_e, mu -> e + gamma, and mu-e conversion on nuclei can be near present limits. For significant range of parameters mu-e conversion can be the most sensitive way to look for such effects.Comment: 19 pages, 5 Postscript figures, LATE

    Nearly Bi-Maximal Neutrino Mixing, Muon g-2 Anomaly and Lepton-Flavor-Violating Processes

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    We interpret the newly observed muon g-2 anomaly in the framework of a leptonic Higgs doublet model with nearly degenerate neutrino masses and nearly bi-maximal neutrino mixing. Useful constraints are obtained on the rates of lepton-flavor-violating rare decays τμγ\tau \to \mu \gamma, μeγ\mu \to e \gamma and τeγ\tau \to e \gamma as well as the μ\mu-ee conversion ratio RμeR_{\mu e}. We find that Γ(μeγ)\Gamma (\mu \to e \gamma), Γ(τeγ)\Gamma (\tau \to e \gamma) and RμeR_{\mu e} depend crucially on possible non-zero but samll values of the neutrino mixing matrix element Ve3V_{e3}, and they are also sensitive to the Dirac-type CP-violating phase. In particular, we show that Γ(τμγ)/mτ5\Gamma (\tau \to \mu \gamma)/m^5_\tau, Γ(μeγ)/mμ5\Gamma (\mu \to e \gamma)/m^5_\mu and Γ(τeγ)/mτ5\Gamma (\tau \to e \gamma)/m^5_\tau are approximately in the ratio 1:2Ve32:2Ve321: 2|V_{e3}|^2: 2|V_{e3}|^2 if Ve3|V_{e3}| is much larger than O(102){\cal O}(10^{-2}), and in the ratio 2(Δmatm2)2:(Δmsun2)2:(Δmsun2)22 (\Delta m^2_{\rm atm})^2: (\Delta m^2_{\rm sun})^2:(\Delta m^2_{\rm sun})^2 if Ve3|V_{e3}| is much lower than O(103){\cal O}(10^{-3}), where Δmatm2\Delta m^2_{\rm atm} and Δmsun2\Delta m^2_{\rm sun} are the corresponding mass-squared differences of atmospheric and solar neutrino oscillations.Comment: LaTex 6 pages (2 PS figures). Phys. Rev. D (in printing

    Report on CE-19: 16-O(p,n)16-F(0-) in the IUCF Cooler

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    TeV-scale seesaw from a multi-Higgs model

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    We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no large flavor changing neutral currents, are satisfied since the extra doublet only has a Yukawa interaction with lepton doublets and right-handed neutrinos, and their masses are heavy of order a TeV-scale. Since active light neutrinos are Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure

    Lepton flavor violating signals of a little Higgs model at the high energy linear e+ee^{+}e^{-} colliders

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    Littlest Higgs (LH)(LH) model predicts the existence of the doubly charged scalars Φ±±\Phi^{\pm\pm}, which generally have large flavor changing couplings to leptons. We calculate the contributions of Φ±±\Phi^{\pm\pm} to the lepton flavor violating (LFV)(LFV) processes liljγl_{i}\to l_{j}\gamma and liljlklkl_{i}\to l_{j}l_{k}l_{k}, and compare our numerical results with the current experimental upper limits on these processes. We find that some of these processes can give severe constraints on the coupling constant YijY_{ij} and the mass parameter MΦM_{\Phi}. Taking into account the constraints on these free parameters, we further discuss the possible lepton flavor violating signals of Φ±±\Phi^{\pm\pm} at the high energy linear e+ee^{+}e^{-} collider (ILC)(ILC) experiments. Our numerical results show that the possible signals of Φ±±\Phi^{\pm\pm} might be detected via the subprocesses e±e±l±l±e^{\pm}e^{\pm}\to l^{\pm}l^{\pm} in the future ILCILC experiments.Comment: 16 pages, 7 figures. Discussions and references added, typos correcte

    Lepton Flavor Violation in the SUSY-GUT Models with Lopsided Mass Matrix

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    The tiny neutrino masses measured in the neutrino oscillation experiments can be naturally explained by the supersymmetric see-saw mechanism. If the supersymmetry breaking is mediated by gravity, the see-saw models may predict observable lepton flavor violating effects. In this work, we investigate the lepton flavor violating process μeγ\mu\to e\gamma in the kind of neutrino mass models based on the idea of the ``lopsided'' form of the charged lepton mass matrix. The constraints set by the muon anomalous magnetic moment are taken into account. We find the present models generally predict a much larger branching ratio of μeγ\mu\to e\gamma than the experimental limit. Conversely, this process may give strong constraint on the lepton flavor structure. Following this constraint we then find a new kind of the charged lepton mass matrix. The feature of the structure is that both the elements between the 2-3 and 1-3 generations are ``lopsided''. This structure produces a very small 1-3 mixing and a large 1-2 mixing in the charged lepton sector, which naturally leads to small Br(μeγ)Br(\mu\to e\gamma) and the LMA solution for the solar neutrino problem.Comment: 24 pages, 8 figure

    Magnetic field-dependent interplay between incoherent and Fermi liquid transport mechanisms in low-dimensional tau phase organic conductors

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    We present an electrical transport study of the 2-dimensional (2D) organic conductor tau-(P-(S,S)-DMEDT-TTF)_2(AuBr)_2(AuBr_2)_y (y = 0.75) at low temperatures and high magnetic fields. The inter-plane resistivity rho_zz increases with decreasing temperature, with the exception of a slight anomaly at 12 K. Under a magnetic field B, both rho_zz and the in-plane resistivity plane rho_xx show a pronounced negative and hysteretic magnetoresistance with Shubnikov de Haas (SdH)oscillations being observed in some (high quality)samples above 15 T. Contrary to the predicted single, star-shaped, closed orbit Fermi surface from band structure calculations (with an expected approximate area of 12.5% of A_FBZ), two fundamental frequencies F_l and F_h are detected in the SdH signal. These orbits correspond to 2.4% and 6.8% of the area of the first Brillouin zone(A_FBZ), with effective masses F_l = 4.0 +/- 0.5 and F_h = 7.3 +/- 0.1. The angular dependence, in tilted magnetic fields of F_l and F_h, reveals the 2D character of the FS and Angular dependent magnetoresistance (AMRO) further suggests a FS which is strictly 2-D where the inter-plane hopping t_c is virtually absent or incoherent. The Hall constant R_xy is field independent, and the Hall mobility increases by a factor of 3 under moderate magnetic fields. Our observations suggest a unique physical situation where a stable 2D Fermi liquid state in the molecular layers are incoherently coupled along the least conducting direction. The magnetic field not only reduces the inelastic scattering between the 2D metallic layers, but it also reveals the incoherent nature of interplane transport in the AMRO spectrum. The apparent ferromagnetism of the hysteretic magnetoresistance remains an unsolved problem.Comment: 33 pages, 11 figure

    Semiconductive and Photoconductive Properties of the Single Molecule Magnets Mn12_{12}-Acetate and Fe8_8Br8_8

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    Resistivity measurements are reported for single crystals of Mn12_{12}-Acetate and Fe8_8Br8_8. Both materials exhibit a semiconductor-like, thermally activated behavior over the 200-300 K range. The activation energy, EaE_a, obtained for Mn12_{12}-Acetate was 0.37 ±\pm 0.05 eV, which is to be contrasted with the value of 0.55 eV deduced from the earlier reported absorption edge measurements and the range of 0.3-1 eV from intramolecular density of states calculations, assuming 2Ea2E_a= EgE_g, the optical band gap. For Fe8_8Br8_8, EaE_a was measured as 0.73 ±\pm 0.1 eV, and is discussed in light of the available approximate band structure calculations. Some plausible pathways are indicated based on the crystal structures of both lattices. For Mn12_{12}-Acetate, we also measured photoconductivity in the visible range; the conductivity increased by a factor of about eight on increasing the photon energy from 632.8 nm (red) to 488 nm (blue). X-ray irradiation increased the resistivity, but EaE_a was insensitive to exposure.Comment: 7 pages, 8 figure
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