1,669 research outputs found

    Texture of fermion mass matrices in partially unified theories

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    We investigate the texture of fermion mass matrices in theories with partial unification (for example SU(2)L×SU(2)R×SU(4)c SU(2)_L\times SU(2)_R\times SU(4)_c) at a scale ∌1012\sim 10^{12} GeV. Starting with the low energy values of the masses and the mixing angles, we find only two viable textures with atmost four texture zeros. One of these corresponds to a somewhat modified Fritzsch textures. A theoretical derivataion of these textures leads to new interesting relations among the masses and the mixing angles.Comment: 10 pages(Latex

    Agents Play Mix-game

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    In mix-game which is an extension of minority game, there are two groups of agents; group1 plays the majority game, but the group2 plays the minority game. This paper studies the change of the average winnings of agents and volatilities vs. the change of mixture of agents in mix-game model. It finds that the correlations between the average winnings of agents and the mean of local volatilities are different with different combinations of agent memory length when the proportion of agents in group 1 increases. This study result suggests that memory length of agents in group1 be smaller than that of agent in group2 when mix-game model is used to simulate the financial markets.Comment: 8 pages, 6 figures, 3 table

    Gauge Field Back-reaction on a Black Hole

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    The order ℏ\hbar fluctuations of gauge fields in the vicinity of a blackhole can create a repulsive antigravity region extending out beyond the renormalized Schwarzschild horizon. If the strength of this repulsive force increases as higher orders in the back-reaction are included, the formation of a wormhole-like object could occur.Comment: 17 pages, three figures available on request, in RevTe

    Echoes of the fifth dimension?

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    In this article we examine the question of whether the highest energy cosmic ray primaries could be ultra relativistic magnetic monopoles. The analysis is performed within the framework of large compact dimensions and TeV scale quantum gravity. Our study indicates that while this hypothesis must be regarded as highly speculative it cannot be ruled out with present data.Comment: Revised version accepted for publication in Physical Review D. The bibliography has been considerably reduced for the journal version due to limited spac

    Sampling of Large Round and Large Square Bales

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    Four hay probes were used to sample four lots of hay. The lots of hay were as follows: alfalfa large round bales, alfalfa large square bales, alfalfa-grass mix large round bales, and alfalfa-grass mix large square bales. Probes used were as follows: E-Z Probe, John Skogberg handcrafted probe, Utah Hay Sampler, and Frontier Mills probe. Six bales from each lot were sampled. Dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) percentages and relative feed value (RFV) were predicted by near infrared reflectance spectroscopy. Bale variation within hay type was much greater than probe variation. Bale variation was significant for all measurements except DM. Probe type only affected NDF% and RFV

    Positivity of Entropy in the Semi-Classical Theory of Black Holes and Radiation

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    Quantum stress-energy tensors of fields renormalized on a Schwarzschild background violate the classical energy conditions near the black hole. Nevertheless, the associated equilibrium thermodynamical entropy ΔS\Delta S by which such fields augment the usual black hole entropy is found to be positive. More precisely, the derivative of ΔS\Delta S with respect to radius, at fixed black hole mass, is found to vanish at the horizon for {\it all} regular renormalized stress-energy quantum tensors. For the cases of conformal scalar fields and U(1) gauge fields, the corresponding second derivative is positive, indicating that ΔS\Delta S has a local minimum there. Explicit calculation shows that indeed ΔS\Delta S increases monotonically for increasing radius and is positive. (The same conclusions hold for a massless spin 1/2 field, but the accuracy of the stress-energy tensor we employ has not been confirmed, in contrast to the scalar and vector cases). None of these results would hold if the back-reaction of the radiation on the spacetime geometry were ignored; consequently, one must regard ΔS\Delta S as arising from both the radiation fields and their effects on the gravitational field. The back-reaction, no matter how "small",Comment: 19 pages, RevTe

    Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector

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    We report on several features present in the energy spectrum from an ultra low-noise germanium detector operated at 2,100 m.w.e. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss several possible causes for an irreducible excess of bulk-like events below 3 keVee, including a dark matter candidate common to the DAMA/LIBRA annual modulation effect, the hint of a signal in CDMS, and phenomenological predictions. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.Comment: 4 pages, 4 figures. v2: submitted version. Minimal changes in wording, one reference adde

    Effective Potential of a Black Hole in Thermal Equilibrium with Quantum Fields

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    Expectation values of one-loop renormalized thermal equilibrium stress-energy tensors of free conformal scalars, spin-12{1 \over 2} fermions and U(1) gauge fields on a Schwarzschild black hole background are used as sources in the semi-classical Einstein equation. The back-reaction and new equilibrium metric are solved for at O(ℏ)O({\hbar}) for each spin field. The nature of the modified black hole spacetime is revealed through calculations of the effective potential for null and timelike orbits. Significant novel features affecting the motions of both massive and massless test particles show up at lowest order in Ï”=(MPl/M)2<1\epsilon= (M_{Pl}/M)^2 < 1, where MM is the renormalized black hole mass, and MPlM_{Pl} is the Planck mass. Specifically, we find the tendency for \underline{stable} circular photon orbits, an increase in the black hole capture cross sections, and the existence of a gravitationally repulsive region associated with the black hole which is generated from the U(1) back-reaction. We also consider the back-reaction arising from multiple fields, which will be useful for treating a black hole in thermal equilibrium with field ensembles belonging to gauge theories.Comment: 25 pages (not including seven figures), VAND-TH-93-6. Typed in Latex, uses RevTex macro

    Wormhole Cosmology and the Horizon Problem

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    We construct an explicit class of dynamic lorentzian wormholes connecting Friedmann-Robertson-Walker (FRW) spacetimes. These wormholes can allow two-way transmission of signals between spatially separated regions of spacetime and could permit such regions to come into thermal contact. The cosmology of a network of early Universe wormholes is discussed.Comment: 13 pages, in RevTe
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