522 research outputs found

    Chiral Fermions and Quadratic Divergences

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    In an approach towards naturalness without supersymmetry, renormalization properties of nonsupersymmetric abelian quiver gauge theories are studied. In the construction based on cyclic groups Z_p the gauge group is U(N)^p, the fermions are all in bifundamentals and the construction allows scalars in adjoints and bifundamentals. Only models without adjoint scalars, however, exhibit both chiral fermions and the absence of one-loop quadratic divergences in the scalar propagator.Comment: 11 page

    Environmental and workplace contamination in the semiconductor industry: implications for future health of the workforce and community.

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    The semiconductor industry has been an enormous worldwide growth industry. At the heart of computer and other electronic technological advances, the environment in and around these manufacturing facilities has not been scrutinized to fully detail the health effects to the workers and the community from such exposures. Hazard identification in this industry leads to the conclusion that there are many sources of potential exposure to chemicals including arsenic, solvents, photoactive polymers and other materials. As the size of the semiconductor work force expands, the potential for adverse health effects, ranging from transient irritant symptoms to reproductive effects and cancer, must be determined and control measures instituted. Risk assessments need to be effected for areas where these facilities conduct manufacturing. The predominance of women in the manufacturing areas requires evaluating the exposures to reproductive hazards and outcomes. Arsenic exposures must also be evaluated and minimized, especially for maintenance workers; evaluation for lung and skin cancers is also appropriate

    Binary Cosmic Strings

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    The properties of cosmic strings have been investigated in detail for their implications in early-universe cosmology. Although many variations of the basic structure have been discovered, with implications for both the microscopic and macroscopic properties of cosmic strings, the cylindrical symmetry of the short-distance structure of the string is generally unaffected. In this paper we describe some mechanisms leading to an asymmetric structure of the string core, giving the defects a quasi-two-dimensional character. We also begin to investigate the consequences of this internal structure for the microscopic and macroscopic physics.Comment: 19 pages; uses harvmac (not included

    Cosmic Background Radiation Temperature Anisotropy: Position of First Doppler Peak

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    The purpose of the Cosmic Background Radiation (CBR) experiments is to measure the temperature anisotropy via the autocorrelation function. The partial wave l1l_1 corresponding to the first Doppler peak caused by baryon-photon oscillations at the surface of last scattering depends on the present density Ω0\Omega_0 and the cosmological constant contribution ΩΛ\Omega_{\Lambda}. We discuss this dependence on the basis of perspicuous figures.Comment: 16 pages LaTeX including four figure

    Magnetic Monopoles in String Theory

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    Magnetic monopole solutions to heterotic string theory are discussed in toroidal compactifications to four spacetime dimensions. Particular emphasis is placed on the relation to previously studied fivebrane solutions in ten dimensions and on the possibility of constructing exact monopole solutions related to symmetric fivebranes.Comment: 24 pages (Corrected title

    CMB with Quintessence: Analytic Approach and CMBFAST

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    A particular kind of quintessence is considered, with equation of motion pQ/ρQ=1p_Q/\rho_Q = -1, corresponding to a cosmological term with time-dependence Λ(t)=Λ(t0)(R(t0)/R(t))P\Lambda(t) = \Lambda(t_0) (R(t_0)/R(t))^{P} which we examine initially for 0P<30 \leq P < 3. Energy conservation is imposed, as is consistency with big-bang nucleosynthesis, and the range of allowed PP is thereby much restricted to 0P<0.20 \leq P < 0.2. The position of the first Doppler peak is computed analytically and the result combined with analysis of high-Z supernovae to find how values of Ωm\Omega_m and ΩΛ\Omega_{\Lambda} depend on PP. Some comparison is made to the CMBFAST public code.Comment: 13 pp LaTeX and 7 postscript figure

    Real Special Geometry

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    We give a coordinate-free description of real manifolds occurring in certain four dimensional supergravity theories with antisymmetric tensor fields. The relevance of the linear multiplets in the compactification of string and five-brane theories is also discussed.Comment: 10 pgs (TeX with Harvmac), CERN-TH.7211/94, UCLA/94/TEP/14, POLFIS-TH.01/9

    Gaugino Condensation in M-theory on S^1/Z_2

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    In the low energy limit of for M-theory on S^1/Z_2, we calculate the gaugino condensate potential in four dimensions using the background solutions due to Horava. We show that this potential is free of delta-function singularities and has the same form as the potential in the weakly coupled heterotic string. A general flux quantization rule for the three-form field of M-theory on S^1/Z_2 is given and checked in certain limiting cases. This rule is used to fix the free parameter in the potential originating from a zero mode of the form field. Finally, we calculate soft supersymmetry breaking terms. We find that corrections to the Kahler potential and the gauge kinetic function, which can be large in the strongly coupled region, contribute significantly to certain soft terms. In particular, for supersymmetry breaking in the T-modulus direction, the small values of gaugino masses and trilinear couplings that occur in the weakly coupled, large radius regime are enhanced to order m_3/2 in M-theory. The scalar soft masses remain small even, in the strong coupling M-theory limit.Comment: 20 pages, LATE
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